ascorbic-acid and Common-Cold

The common cold had resulted in significant economic and social burden worldwide. The effect of vitamin C on preventing common cold in healthy adults has been investigated extensively, but not that of other micronutrients. Thus, we aim to assess the effects of providing micronutrients singly through oral means, on cold incidence, and/or management (in terms of cold duration and symptom severity) in healthy adults from systematically searched randomized controlled trials. From four electronic databases, 660 identified studies were screened and data were extracted from 20 studies (zinc, 10; vitamin D, 8; and vitamins A and E, 2). The quality of selected studies was assessed using the Cochrane risk of bias tool and certainty in the outcomes was assessed with the Grading of Recommendations Assessment, Development and Evaluation approach. The review found that micronutrients supplementation, except vitamin C, may not prevent cold incidence or reduce symptom severity among healthy adults. However, zinc supplementation was observed to potentially reduce cold duration by 2.25 days (when zinc is provided singly, 95% CI: -3.39, -1.12). This suggests that zinc supplementation may reduce the overall burden due to common cold among healthy adults.

Topics: Adolescent; Adult; Aged; Ascorbic Acid; Common Cold; Dietary Supplements; Humans; Incidence; Micronutrients; Middle Aged; Odds Ratio; Randomized Controlled Trials as Topic; Severity of Illness Index; Vitamin A; Vitamin D; Vitamin E; Zinc

To investigate whether vitamin C performs well as a supplemental treatment for common cold.. After systematically searching through the National Library of Medicine (PubMed), Cochrane Library, Elsevier, China National Knowledge Infrastructure (CNKI), VIP databases, and Wanfang databases, 10 randomized controlled trials were selected for our meta-analysis with RevMan 5.3 software. Published in China, all 10 studies evaluated the effect of combined vitamin C and antiviral therapy for the treatment of common cold.. The total efficacy (RR = 1.27, 95% CI (1.08, 1.48),. Vitamin C could be used as a supplementary therapy along with antiviral regimens to relieve patients from the symptoms of common cold.

Topics: Adult; Antiviral Agents; Ascorbic Acid; Child, Preschool; Common Cold; Dietary Supplements; Female; Humans; Male; Randomized Controlled Trials as Topic; Young Adult

From Pauling's theories to the present, considerable understanding has been acquired of both the physiological role of vitamin C and of the impact of vitamin C supplementation on the health. Although it is well known that a balanced diet which satisfies the daily intake of vitamin C positively affects the immune system and reduces susceptibility to infections, available data do not support the theory that oral vitamin C supplements boost immunity. No current clinical recommendations support the possibility of significantly decreasing the risk of respiratory infections by using high-dose supplements of vitamin C in a well-nourished general population. Only in restricted subgroups (e.g., athletes or the military) and in subjects with a low plasma vitamin C concentration a supplementation may be justified. Furthermore, in categories at high risk of infection (i.e., the obese, diabetics, the elderly, etc.), a vitamin C supplementation can modulate inflammation, with potential positive effects on immune response to infections. The impact of an extra oral intake of vitamin C on the duration of a cold and the prevention or treatment of pneumonia is still questioned, while, based on critical illness studies, vitamin C infusion has recently been hypothesized as a treatment for COVID-19 hospitalized patients. In this review, we focused on the effects of vitamin C on immune function, summarizing the most relevant studies from the prevention and treatment of common respiratory diseases to the use of vitamin C in critical illness conditions, with the aim of clarifying its potential application during an acute SARS-CoV2 infection.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Ascorbic Acid; Child; Child, Preschool; Common Cold; COVID-19; COVID-19 Drug Treatment; Critical Illness; Dietary Supplements; Female; Humans; Infant; Male; Middle Aged; SARS-CoV-2; Vitamins; Young Adult

To investigate whether vitamin C is effective in the treatment of the common cold.. After systematically searching the National Library of Medicine (PubMed), Cochrane Library, Elsevier, China National Knowledge Infrastructure (CNKI), VIP databases, and WANFANG databases, 9 randomized placebo-controlled trials were included in our meta-analysis in RevMan 5.3 software, all of which were in English.. In the evaluation of vitamin C, administration of extra therapeutic doses at the onset of cold despite routine supplementation was found to help reduce its duration (mean difference (MD) = -0.56, 95% confidence interval (CI) [-1.03, -0.10], and P = 0.02), shorten the time of confinement indoors (MD = -0.41, 95% CI [-0.62, -0.19], and P = 0.0002), and relieve the symptoms associated with it, including chest pain (MD = -0.40, 95% CI [-0.77, -0.03], and P = 0.03), fever (MD = -0.45, 95% CI [-0.78, -0.11], and P = 0.009), and chills (MD = -0.36, 95% CI [-0.65, -0.07], and P = 0.01).. Extra doses of vitamin C could benefit some patients who contract the common cold despite taking daily vitamin C supplements.

Topics: Ascorbic Acid; Common Cold; Humans; Randomized Controlled Trials as Topic; Vitamins

The common cold is one of the most common diseases. It is generally believed that the consumption of vitamin C prevents its appearance, but the actual efficacy of this measure is controversial.. To answer this question we used Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach.. We identified eight systematic reviews including 45 studies overall, of which 31 were randomized trials. We concluded the consumption of vitamin C does not prevent the incidence of common cold.. El resfrío común es una enfermedad muy frecuente. Existe la creencia que el consumo de vitamina C previene su aparición, pero la real eficacia de esta medida es controvertida.. Para responder esta pregunta utilizamos Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante búsquedas en múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, reanalizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE.. Identificamos ocho revisiones sistemáticas que en conjunto incluyen 45 estudios primarios, de los cuales 31 corresponden a ensayos aleatorizados. Concluimos que el consumo de vitamina C no previene la aparición del resfrío común.

Topics: Antioxidants; Ascorbic Acid; Common Cold; Databases, Factual; Humans; Randomized Controlled Trials as Topic; Treatment Outcome

The common cold causes great morbidity throughout the world and there are no effective therapeutic agents against it. There is a belief that consuming vitamin C during a cold episode would help reduce duration and severity of symptoms. However, there is controversy about this claim.. To answer this question we used Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach.. We identified four systematic reviews that included eight primary studies overall, of which seven were randomized trials. We concluded vitamin C has minimal or no impact on the duration of common cold or in the number of days at home or out of work.. El resfrío común causa una gran morbilidad en todo el mundo y no se cuenta con agentes terapéuticos eficaces contra éste. Existe la creencia de que ingerir vitamina C durante un episodio de resfrío ayuda a disminuir la duración y severidad de los síntomas, sin embargo existe controversia respecto a esta afirmación.. Para responder esta pregunta utilizamos Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante búsquedas en múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, reanalizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE.. Identificamos cuatro revisiones sistemáticas que en conjunto incluyeron ocho estudios primarios, de los cuales siete son ensayos aleatorizados. Concluimos que la vitamina C tiene un impacto mínimo o nulo en la duración del resfrío y en los días en casa o sin trabajar.

Topics: Ascorbic Acid; Common Cold; Databases, Factual; Humans; Randomized Controlled Trials as Topic; Severity of Illness Index; Time Factors; Treatment Outcome

In the early literature, vitamin C deficiency was associated with pneumonia. After its identification, a number of studies investigated the effects of vitamin C on diverse infections. A total of 148 animal studies indicated that vitamin C may alleviate or prevent infections caused by bacteria, viruses, and protozoa. The most extensively studied human infection is the common cold. Vitamin C administration does not decrease the average incidence of colds in the general population, yet it halved the number of colds in physically active people. Regularly administered vitamin C has shortened the duration of colds, indicating a biological effect. However, the role of vitamin C in common cold treatment is unclear. Two controlled trials found a statistically significant dose-response, for the duration of common cold symptoms, with up to 6-8 g/day of vitamin C. Thus, the negative findings of some therapeutic common cold studies might be explained by the low doses of 3-4 g/day of vitamin C. Three controlled trials found that vitamin C prevented pneumonia. Two controlled trials found a treatment benefit of vitamin C for pneumonia patients. One controlled trial reported treatment benefits for tetanus patients. The effects of vitamin C against infections should be investigated further.

Topics: Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Common Cold; Humans; Pneumonia; Tetanus; Vitamins

Vitamin C has been suggested as beneficial in preventing and curing the common cold, decreasing the incidence of preterm delivery and preeclampsia, decreasing risk of cancer and cardiovascular disease, and improving the quality of life by inhibiting blindness and dementia. In this article, we review the hypothesized mechanisms of these purported health benefits and the evidence behind such claims.

Topics: Antioxidants; Ascorbic Acid; Ascorbic Acid Deficiency; Common Cold; Dementia; Female; Humans; Neoplasms; Obstetric Labor, Premature; Pre-Eclampsia; Pregnancy; Vision Disorders; Vitamins

Topics: Acetaminophen; Analgesics, Non-Narcotic; Anti-Inflammatory Agents, Non-Steroidal; Antitussive Agents; Ascorbic Acid; Cholinergic Antagonists; Common Cold; Dietary Supplements; Drug Combinations; Echinacea; Exercise Therapy; Garlic; Hand Disinfection; Histamine Antagonists; Honey; Humans; Ipratropium; Nasal Decongestants; Panax; Plant Extracts; Probiotics; Terpenes; Vitamin D; Zinc

Vitamin C (ascorbic acid) for preventing and treating the common cold has been a subject of controversy for 70 years.. To find out whether vitamin C reduces the incidence, the duration or severity of the common cold when used either as a continuous regular supplementation every day or as a therapy at the onset of cold symptoms.. We searched CENTRAL 2012, Issue 11, MEDLINE (1966 to November week 3, 2012), EMBASE (1990 to November 2012), CINAHL (January 2010 to November 2012), LILACS (January 2010 to November 2012) and Web of Science (January 2010 to November 2012). We also searched the U.S. National Institutes of Health trials register and WHO ICTRP on 29 November 2012.. We excluded trials which used less than 0.2 g per day of vitamin C and trials without a placebo comparison. We restricted our review to placebo-controlled trials.. Two review authors independently extracted data. We assessed 'incidence' of colds during regular supplementation as the proportion of participants experiencing one or more colds during the study period. 'Duration' was the mean number of days of illness of cold episodes.. Twenty-nine trial comparisons involving 11,306 participants contributed to the meta-analysis on the risk ratio (RR) of developing a cold whilst taking vitamin C regularly over the study period. In the general community trials involving 10,708 participants, the pooled RR was 0.97 (95% confidence interval (CI) 0.94 to 1.00). Five trials involving a total of 598 marathon runners, skiers and soldiers on subarctic exercises yielded a pooled RR of 0.48 (95% CI 0.35 to 0.64).Thirty-one comparisons examined the effect of regular vitamin C on common cold duration (9745 episodes). In adults the duration of colds was reduced by 8% (3% to 12%) and in children by 14% (7% to 21%). In children, 1 to 2 g/day vitamin C shortened colds by 18%. The severity of colds was also reduced by regular vitamin C administration.Seven comparisons examined the effect of therapeutic vitamin C (3249 episodes). No consistent effect of vitamin C was seen on the duration or severity of colds in the therapeutic trials.The majority of included trials were randomised, double-blind trials. The exclusion of trials that were either not randomised or not double-blind had no effect on the conclusions.. The failure of vitamin C supplementation to reduce the incidence of colds in the general population indicates that routine vitamin C supplementation is not justified, yet vitamin C may be useful for people exposed to brief periods of severe physical exercise. Regular supplementation trials have shown that vitamin C reduces the duration of colds, but this was not replicated in the few therapeutic trials that have been carried out. Nevertheless, given the consistent effect of vitamin C on the duration and severity of colds in the regular supplementation studies, and the low cost and safety, it may be worthwhile for common cold patients to test on an individual basis whether therapeutic vitamin C is beneficial for them. Further therapeutic RCTs are warranted.

Topics: Administration, Oral; Adult; Age Factors; Ascorbic Acid; Child; Common Cold; Humans; Randomized Controlled Trials as Topic

Topics: Ascorbic Acid; Common Cold; Drug Prescriptions; Humans; Practice Guidelines as Topic; Treatment Outcome

Topics: Ascorbic Acid; Cholinergic Antagonists; Common Cold; Echinacea; Humans; Ipratropium; Nonprescription Drugs; Pelargonium; Phytotherapy; Respiratory System Agents; Trace Elements; Vitamins; Zinc

Topics: Adolescent; Anti-Bacterial Agents; Ascorbic Acid; Child; Child, Preschool; Common Cold; Echinacea; Humans; Infant; Nonprescription Drugs; Phytotherapy; Sodium Chloride; Therapeutic Irrigation; Zinc

Vitamin C and zinc play important roles in nutrition, immune defence and maintenance of health. Intake of both is often inadequate, even in affluent populations. The common cold continues to place a great burden on society in terms of suffering and economic loss. After an overview of the literature on the effects of the separate administration of either vitamin C or zinc against the common cold, this article presents data from two preliminary, double-blind, randomized, placebo-controlled trials, conducted with a combination of 1000 mg vitamin C plus 10 mg zinc in patients with the common cold. In both studies, a nonsignificant reduction of rhinorrhoea duration (range 9-27%) was seen. In pooled analyses of both studies (n=94), vitamin C plus zinc was significantly more efficient than placebo at reducing rhinorrhoea over 5 days of treatment. Furthermore, symptom relief was quicker and the product was well tolerated. In view of the burden associated with the common cold, supplementation with vitamin C plus zinc may represent an efficacious measure, with a good safety profile, against this infectious viral disease.

Topics: Ascorbic Acid; Common Cold; Dose-Response Relationship, Drug; Drug Therapy, Combination; Humans; Randomized Controlled Trials as Topic; Zinc

To review the evidence supporting complementary and alternative medicine approaches to treatment and prevention of the common cold in adults.. MEDLINE, EMBASE, and the Cochrane Database of Systematic Reviews were searched from January 1966 to September 2009 combining the key words common cold or influenza with echinacea, garlic, ginseng, probiotics, vitamin C, and zinc. Clinical trials and prospective studies were included.. For prevention, vitamin C demonstrated benefit in a large meta-analysis, with possibly increased benefit in patients subjected to cold stress. There is inconsistent evidence for Asian ginseng (Panax ginseng) and North American ginseng (Panax quinquefolius). Allicin was highly effective in 1 small trial. For treatment, Echinacea purpurea is the most consistently useful variety; it was effective in 5 of 6 trials. Zinc lozenges were effective in 5 of 9 trials, likely owing to dose and formulation issues. Overall, the evidence suggests no benefit from probiotics for prevention or treatment of the common cold.. Vitamin C can be recommended to Canadian patients for prevention of the common cold. There is moderate evidence supporting the use of Echinacea purpurea and zinc lozenges for treatment. Ginseng and allicin warrant further research.

Topics: Ascorbic Acid; Common Cold; Complementary Therapies; Dietary Supplements; Disulfides; Echinacea; Garlic; Gluconates; Glycine; Humans; Panax; Plant Extracts; Probiotics; Sulfinic Acids; Vitamins; Zinc

Each year, children suffer up to 5 colds and adults have two to three infections, leading to time off school or work, and considerable discomfort. Most symptoms resolve within 1 week, but coughs often persist for longer.. We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments for common cold? We searched: Medline, Embase, The Cochrane Library, and other important databases up to January 2010 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).. We found 21 systematic reviews and RCTs that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.. In this systematic review we present information relating to the effectiveness and safety of the following interventions: analgesics or anti-inflammatory drugs, antibiotics, antihistamines, decongestants for short-term and for long-term relief, decongestants plus antihistamines, echinacea, steam inhalation, vitamin C, and zinc (intranasal gel or lozenges).

Topics: Anti-Inflammatory Agents, Non-Steroidal; Ascorbic Acid; Common Cold; Echinacea; Humans; Nasal Decongestants; Nonprescription Drugs

Occurrence of influenza pandemics is a worldwide phenomenon and a significant cause of mortality and morbidity throughout the globe. It is due to mutations in the influenza virus genetic material creating antigenic drift of pathogenic viral proteins resulting in emergence of new influenza virus strains. Therefore, the vaccines available for prevention of influenza offer no protection against influenza pandemics caused by new virus strains. Moreover, the existing drugs used to combat influenza may be ineffective to treat influenza pandemics due to the emergence of drug resistance in the pandemic virus strain. Therefore, a working strategy must be developed to combat influenza pandemics. In this review we have addressed this problem and reviewed the published studies on ascorbic acid in the common cold and influenza and laboratory studies on the effect of ascorbic acid on influenza virus. We have also correlated the clinical and laboratory studies and developed a hypothesis to prevent influenza pandemics.

Topics: Administration, Inhalation; Administration, Oral; Antiviral Agents; Ascorbic Acid; Common Cold; Dietary Supplements; Disease Outbreaks; Humans; Influenza Vaccines; Influenza, Human

To present a critical evaluation of the current evidence concerning the therapeutic value of vitamin C for the prophylaxis and treatment of the common cold.. Cochrane, PubMed, Natural Standard, and the National Center for Complementary and Alternative Medicine databases were searched to identify and acquire primary research reports, literature reviews, and secondary analyses related to the clinical objective. Published clinical trials, literature reviews, meta-analyses, and systematic reviews were evaluated for evidence-based practice implications.. Vitamin C is frequently used for the treatment and prophylaxis of the common cold; however, no published recommendations were found in a review of the nurse practitioner literature that specifically address the efficacy of vitamin C for the common cold. Our literature review revealed that vitamin C is not effective at preventing the common cold in the general adult population; however, it is effective at preventing colds when consumed regularly by athletes training in subarctic conditions. We also found that regular vitamin C consumption may reduce the duration of cold symptoms in both adults and children, but it does not decrease the severity of cold symptoms.. NPs should counsel their patients that regular vitamin C consumption may decrease the duration of cold symptoms, but does not affect symptom severity or act as a prophylaxis.

Topics: Adult; Ascorbic Acid; Child; Common Cold; Evidence-Based Practice; Female; Humans; Male; Nurse Practitioners; Nutrition Policy; Nutritional Requirements; Nutritional Sciences; Patient Education as Topic; Primary Health Care; Primary Prevention; Research Design; Severity of Illness Index; Time Factors; Vitamins

Topics: Adult; Antioxidants; Ascorbic Acid; C-Reactive Protein; Child; Common Cold; Communicable Diseases; Dose-Response Relationship, Drug; Humans; Immunity, Cellular; Immunocompetence; Immunoglobulins; Immunologic Deficiency Syndromes; Micronutrients; Nutritional Requirements; Phagocytosis; Randomized Controlled Trials as Topic; Vitamin D; Vitamin E

The common cold is a viral illness that affects persons of all ages, prompting frequent use of over-the-counter and prescription medications and alternative remedies. Treatment focuses on relieving symptoms (e.g., cough, nasal congestion, rhinorrhea). Dextromethorphan may be beneficial in adults with cough, but its effectiveness has not been demonstrated in children and adolescents. Codeine has not been shown to effectively treat cough caused by the common cold. Although hydrocodone is widely used and has been shown to effectively treat cough caused by other conditions, the drug has not been studied in patients with colds. Topical (intranasal) and oral nasal decongestants have been shown to relieve nasal symptoms and can be used in adolescents and adults for up to three days. Antihistamines and combination antihistamine/decongestant therapies can modestly improve symptoms in adults; however, the benefits must be weighed against potential side effects. Newer nonsedating antihistamines are ineffective against cough. Topical ipratropium, a prescription anticholinergic, relieves nasal symptoms in older children and adults. Antibiotics have not been shown to improve symptoms or shorten illness duration. Complementary and alternative therapies (i.e., Echinacea, vitamin C, and zinc) are not recommended for treating common cold symptoms; however, humidified air and fluid intake may be useful without adverse side effects. Vitamin C prophylaxis may modestly reduce the duration and severity of the common cold in the general population and may reduce the incidence of the illness in persons exposed to physical and environmental stresses.

Topics: Adult; Antitussive Agents; Ascorbic Acid; Cerebrospinal Fluid Rhinorrhea; Child; Common Cold; Echinacea; Fluid Therapy; Histamine H1 Antagonists; Humans; Humidity; Nasal Decongestants; Phytotherapy; Zinc Compounds

Topics: Ascorbic Acid; Ascorbic Acid Deficiency; Asthma; Cardiovascular Diseases; Cataract; Common Cold; Humans; Nutrition Policy; Nutritional Requirements

The role of vitamin C (ascorbic acid) in the prevention and treatment of the common cold has been a subject of controversy for 60 years, but is widely sold and used as both a preventive and therapeutic agent.. To discover whether oral doses of 0.2 g or more daily of vitamin C reduces the incidence, duration or severity of the common cold when used either as continuous prophylaxis or after the onset of symptoms.. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2006); MEDLINE (1966 to December 2006); and EMBASE (1990 to December 2006).. Papers were excluded if a dose less than 0.2 g per day of vitamin C was used, or if there was no placebo comparison.. Two review authors independently extracted data and assessed trial quality. 'Incidence' of colds during prophylaxis was assessed as the proportion of participants experiencing one or more colds during the study period. 'Duration' was the mean days of illness of cold episodes.. Thirty trial comparisons involving 11,350 study participants contributed to the meta-analysis on the relative risk (RR) of developing a cold whilst taking prophylactic vitamin C. The pooled RR was 0.96 (95% confidence intervals (CI) 0.92 to 1.00). A subgroup of six trials involving a total of 642 marathon runners, skiers, and soldiers on sub-arctic exercises reported a pooled RR of 0.50 (95% CI 0.38 to 0.66). Thirty comparisons involving 9676 respiratory episodes contributed to a meta-analysis on common cold duration during prophylaxis. A consistent benefit was observed, representing a reduction in cold duration of 8% (95% CI 3% to 13%) for adults and 13.6% (95% CI 5% to 22%) for children. Seven trial comparisons involving 3294 respiratory episodes contributed to the meta-analysis of cold duration during therapy with vitamin C initiated after the onset of symptoms. No significant differences from placebo were seen. Four trial comparisons involving 2753 respiratory episodes contributed to the meta-analysis of cold severity during therapy and no significant differences from placebo were seen.. The failure of vitamin C supplementation to reduce the incidence of colds in the normal population indicates that routine mega-dose prophylaxis is not rationally justified for community use. But evidence suggests that it could be justified in people exposed to brief periods of severe physical exercise or cold environments.

Topics: Administration, Oral; Ascorbic Acid; Common Cold; Humans; Randomized Controlled Trials as Topic; Respiratory Tract Infections

Topics: Anti-Bacterial Agents; Ascorbic Acid; Common Cold; Echinacea; Histamine H1 Antagonists; Humans; Nasal Decongestants; Phytotherapy; Plant Extracts; Steam; Zinc

Topics: Ascorbic Acid; Common Cold; Humans; Randomized Controlled Trials as Topic

Topics: Ascorbic Acid; Common Cold; Echinacea; Histamine H1 Antagonists; Humans; Phytotherapy; Steam; Vitamins; Zinc

To review the seven Cochrane reviews of non-antibiotic treatment for the common cold.. Each Cochrane review was read and summarized, and results presented as relative risks and, where possible, numbers needed to treat.. The main theme that runs through these Cochrane reviews is the variable quality of the primary studies. In general, the reviewers are fairly cautious about the benefits of any of the treatments other than first-dose decongestants and antihistamine-decongestant combinations. For antihistamines alone, the reviewers were clear about the lack of efficacy except in the high-quality studies in which a global improvement in symptoms was noted. Some studies were statistically significant, but the Cochrane reviewers were guarded about how clinically significant they were. For Echinacea, problems were found with the quality of the studies and the wide range of different forms of this substance. Heated humidified air seemed to be effective in the UK and Israel, but not the USA, making definitive statements about efficacy difficult. Over-the-counter medication for cough seemed to have no documented benefit in children under the age of 5 years. Letosteine (a mucolytic) may be effective in children but is not available in the UK. Bisolvon (a mucolytic) was found to be effective for cough in only one study. For older children and adults, dextromethorphan may be effective (two out of three studies showed benefit), and guiafenesin (an expectorant) showed mixed benefit in two trials. Dexbrompheniramine (a sedating antihistamine)/pseudoephedrine (6 mg/120 mg twice daily for 1 week) was significantly more effective than placebo for severity of cough, whereas, in another study, loratadine (a non-sedating antihistamine)/pseudoephedrine (5 mg/120 mg twice daily for 4 days) did not show any difference between the study groups. Vitamin C may have a small role in preventing the common cold, with possibly a greater role in high-intensity physical activity and sub-arctic conditions. Zinc lozenges seemed to be effective, but the issue of unblinding due to taste was a methodological issue of concern to the reviewers. The benefits and harms are calculated as numbers needed to treat for one person to benefit (NNTB) and numbers needed to treat for one person to harm (NNTH), and were calculated by the author.. Most non-antibiotic treatments for the common cold are probably not effective. The most promising are dextromethorphan, bisolvon and guiaphenesin for cough, antihistamine-decongestant combinations for a wide range of symptoms, nasal decongestants (at least for the first dose) and possibly zinc lozenges.

Topics: Adult; Ascorbic Acid; Child; Common Cold; Echinacea; Evidence-Based Medicine; Histamine H1 Antagonists; Hot Temperature; Humans; Humidity; Nasal Decongestants; Nonprescription Drugs; Phytotherapy; Placebos; Randomized Controlled Trials as Topic; Respiratory Tract Infections; Zinc

The role of oral vitamin C (ascorbic acid) in the prevention and treatment of the common cold has been a subject of controversy for at least sixty years. Public interest in the topic continues to be high and vitamin C continues to be widely sold and used as a preventive and therapeutic agent for this common ailment.. To discover whether oral vitamin C in doses of 200 mg or more daily, reduces the incidence, duration or severity of the common cold when used either as continuous prophylaxis or after the onset of cold symptoms.. This updated review added to earlier searches, a full search of the following electronic databases: the Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2004); MEDLINE (January 1966 to June 2004); and EMBASE (1990 to June 2004).. Papers were excluded if a dose less than 200 mg daily of vitamin C was used; if there was no placebo comparison; if methods of outcome assessment were inadequately described; and if the report did not record any of the three study outcomes (incidence, duration or severity) in sufficient detail to enter into the meta-analysis. Three criteria of study quality were assessed: Jadad scores, placebo distinguish-ability, and allocation concealment.. Two reviewers independently extracted data and assessed trial quality. 'Incidence' of colds during prophylaxis was assessed as the proportion of participants experiencing one or more colds during the study period. 'Duration' was the mean days of illness of cold episodes and 'severity' of these episodes was assessed by days confined indoors, off work or school. or by symptom severity scores.. Twenty-nine trial comparisons involving 11,077 study participants contributed to the meta-analysis on the relative risk (RR) of developing a cold while taking prophylaxis. The pooled RR was 0.96 (95% CI 0.92 to 1.00). A subgroup of six trials that involved a total of 642 marathon runners, skiers, and soldiers on sub-arctic exercises reported a pooled RR of 0.50 (95%CI 0.38 to 0.66). Thirty comparisons that involved 9,676 respiratory episodes contributed to the meta-analysis on common cold duration during prophylaxis . A consistent benefit was observed, representing a reduction in cold duration of 8% (95% CI 3% to 13%) for adult participants and 13.5% (95% CI 5% to 21%) for child participants. Fifteen trial comparisons that involved 7,045 respiratory episodes contributed to the meta-analysis of severity of episodes experienced while on prophylaxis. The pooled results revealed a difference favouring those on vitamin C when days confined to home and off work or school were taken as a measure of severity (p = 0.02), and when restricting to studies which used symptom severity scores (p = 0.16), and for the both measures of severity combined (p = 0.004). Seven trial comparisons that involved 3,294 respiratory episodes contributed to the meta-analysis of cold duration during therapy with vitamin C that was initiated after the onset of cold symptoms, and no significant difference from placebo was seen. Four trial comparisons that involved 2,753 respiratory episodes, contributed to the meta-analysis of cold severity during therapy and no significant difference from placebo was seen.In laboratory studies, differing methods of artificial transmission of virus to vitamin C or placebo treated volunteers in residential experiments gave different results. Volunteers infected by nasal installation showed small or no benefit from vitamin C, whereas a group who were infected more naturally, reported less severe symptom severity scores (p = 0.04).. The failure of vitamin C supplementation to reduce the incidence of colds in the normal population indicates that routine mega-dose prophylaxis is not rationally justified for community use. But evidence shows that it could be justified in persons exposed to brief periods of severe physical exercise and/or cold environments. Also, the consistent and statistically significant small benefits on duration and severity for those using regular vitamin C prophylaxis indicates that vitamin C plays some role in respiratory defence mechanisms. The trials in which vitamin C was introduced at the onset of colds as therapy did not show any benefit in doses up to 4 grams daily, but one large trial reported equivocal benefit from an 8 gram therapeutic dose at onset of symptoms.

Topics: Administration, Oral; Ascorbic Acid; Common Cold; Humans; Respiratory Tract Infections

For decades, investigators have strived to elucidate the pathogenesis, and hence a treatment, for the common cold. Therapy has been tried with a variety of agents, ranging from anecdotal folk remedies, to well-designed medications. Measures primarily directed to relieve the symptoms of the common cold, rather than specific antimicrobial agents, are the current main stay of therapy. Millions of patients would benefit from an easy-to-perform diagnostic test and specific therapy that works quickly, shortening the duration of illness and preventing further spread of infection.

Topics: Anti-Bacterial Agents; Anti-Inflammatory Agents, Non-Steroidal; Antiviral Agents; Ascorbic Acid; Common Cold; Drug Interactions; Histamine Antagonists; Humans; Nasal Decongestants

Topics: Anti-Bacterial Agents; Ascorbic Acid; Common Cold; Echinacea; Histamine H1 Antagonists; Humans; Nasal Decongestants; Phytotherapy; Plant Preparations; Respiratory Tract Infections; Zinc

The role of oral ascorbic acid (vitamin C) in the prevention and treatment of colds remains controversial despite many controlled trials. There have also been a number of efforts to synthesize and/or overview the results of these trials, and controversy over what these overviews tell us.. The objective of this review was to answer the following two questions: (1) Does regular high dosage supplementation with vitamin C reduce the incidence of colds? (2) Does taking vitamin C in high doses at the onset of a cold have a therapeutic effect?. This review currently deals only with published trials from two previously published reviews by Kleijnen 1989 and Hemila 1992.. Randomised and non-randomised trials of vitamin C taken to prevent or treat the common cold.. Two reviewers independently extracted data and assessed trial quality.. Thirty trials were included. The quality of the included trials was variable. Vitamin C in doses as high as one gram daily for several winter months, had no consistent beneficial effect on incidence of the common cold. For both preventive and therapeutic trials, there was a consistently beneficial but generally modest therapeutic effect on duration of cold symptoms. This effect was variable, ranging from -0.07% to a 39% reduction in symptom days. The weighted difference across all of the studies revealed a reduction of a little less than half a symptom day per cold episode, representing an 8% to 9% reduction in symptom days. There was no clear indication of the relative benefits of different regimes or vitamin C doses. However in trials that tested vitamin C after cold symptoms occurred, there was some evidence that a large dose produced greater benefits than lower doses.. Long term daily supplementation with vitamin C in large doses daily does not appear to prevent colds. There appears to be a modest benefit in reducing duration of cold symptoms from ingestion of relatively high doses of vitamin C. The relation of dose to therapeutic benefit needs further exploration.

Topics: Administration, Oral; Ascorbic Acid; Common Cold; Humans; Respiratory Tract Infections

So far over 60 studies have examined the effects of vitamin C on the common cold. No effect on common cold incidence was observed in the six largest studies, indicating that vitamin C has no preventive effects in normally nourished subjects in the Western countries. There are, however, smaller studies reporting benefit. In three trials of subjects under heavy acute physical stress, common cold incidence decreased by on average 50%, and in four trials of British males common cold incidence decreased by on average 30% in the vitamin C groups. The dietary vitamin C intake in the UK is low, and consequently the benefit may be due to the correction of marginal deficiency, rather than high vitamin doses. Regular vitamin C supplementation (> or =1 g/day) has quite consistently reduced the duration of colds, but the size of the benefit has varied greatly. In the four largest studies the duration of colds was reduced only by 5%. In two of these studies, however, absence from school and work was reduced by 14-21% per episode, which may have practical importance. Three controlled studies recorded a reduction of at least 80% in the incidence of pneumonia in the vitamin C group, and one randomised trial reported substantial treatment benefit from vitamin C in elderly UK patients hospitalized with pneumonia or bronchitis. It seems that the preventive effects of supplementation are mainly limited to subjects with low dietary vitamin C intake, but therapeutic effects may occur in wider population groups. Further carefully designed trials are needed to explore the effects of vitamin C.

Topics: Ascorbic Acid; Common Cold; Dietary Supplements; Humans; Incidence; Respiratory Tract Infections; Treatment Outcome; United Kingdom

Topics: Adrenergic alpha-Agonists; Anti-Bacterial Agents; Anti-Inflammatory Agents, Non-Steroidal; Antiviral Agents; Ascorbic Acid; Cholinergic Antagonists; Common Cold; Drug Combinations; Glucocorticoids; Histamine H1 Antagonists; Humans; Interferons; Zinc Compounds

Although the role of vitamin C in common cold incidence had been studied extensively, the level of vitamin C intake has not been unequivocally shown to affect the incidence of colds. In the present study the six largest vitamin C supplementation (> or = 1 g/d) studies, including over 5000 episodes in all, have been analysed, and it is shown that common cold incidence is not reduced in the vitamin C-supplemented groups compared with the placebo groups (pooled rate ratio (RR) 0.99; 95% CI 0.93, 1.04). Consequently these six major studies give no evidence that high-dose vitamin C supplementation decreases common cold incidence in ordinary people. Nevertheless, the analysis was continued with the hypothesis that vitamin C intake may affect common cold susceptibility in specific groups of people. It was assumed that the potential effect of supplementation might be most conspicuous in subjects with low dietary vitamin C intake. The average vitamin C intake has been rather low in the UK and plasma vitamin C concentrations are in general lower in males than in females. In four studies with British females vitamin C supplementation had no marked effect on common cold incidence (pooled RR 0.95; 95% CI 0.86, 1.04). However, in four studies with British male schoolchildren and students a statistically highly significant reduction in common cold incidence was found in groups supplemented with vitamin C (pooled RR 0.70; 95% CI 0.60, 0.81). Thus, these studies with British males indicate that vitamin C intake has physiological effects on susceptibility to common cold infections, although the effect seems quantitatively meaningful only in limited groups of people and is not very large.

Topics: Adolescent; Adult; Ascorbic Acid; Child; Clinical Trials as Topic; Common Cold; Disease Susceptibility; Female; Humans; Incidence; Male; Treatment Failure

In 1970 Linus Pauling claimed that vitamin C prevents and alleviates the episodes of the common cold. Pauling was correct in concluding from trials published up till then, that in general vitamin C does have biological effects on the common cold, but he was rather over-optimistic as regards the size of benefit. His quantitative conclusions were based on a single placebo-controlled trial on schoolchildren in a skiing camp in the Swiss Alps, in which a significant decrease in common cold incidence and duration in the group administered 1 g/day of vitamin C was found. As children in a skiing camp are not a representative sample of the general population, Pauling's extrapolation to the population at large was too bold, erring as to the magnitude of the effect. Nevertheless, Pauling's general conclusion that vitamin C has physiological effects on the common cold is of major importance as it conflicts with the prevailing consensus that the only physiological effect of vitamin C on human beings is to prevent scurvy.

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Dietary Supplements; Humans; Incidence; Severity of Illness Index

Topics: Antiviral Agents; Ascorbic Acid; Child; Child, Preschool; Common Cold; Female; Hand Disinfection; Histamine H1 Antagonists; Humans; Infant; Interferon-alpha; Male

Since 1971, 21 placebo-controlled studies have been made to establish whether vitamin C at a dosage of > or = 1 g/day affects the common cold. These studies have not found any consistent evidence that vitamin C supplementation reduces the incidence of the common cold in the general population. Nevertheless, in each of the 21 studies, vitamin C reduced the duration of episodes and the severity of the symptoms of the common cold by an average of 23%. However, there have been large variations in the benefits observed, and clinical significance cannot be clearly inferred from the results. Still, the consistency of the results indicates that the role of vitamin C in the treatment of the common cold should be reconsidered.

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Humans; Incidence

Increasing evidence is accumulating that a synergistic role of the so-called antioxidant vitamins (C, E, beta-carotene) may have a dominant role in the prevention of cancer, cardiovascular diseases and cataract formation. Controversy still exists regarding the optimum intake of vitamin C. This is partly due to lack of accurate and easily accessible health-relevant end-points, and lack of knowledge of the role of vitamin C in biochemical functions. Today, it is clearly recognized and broadly accepted that optimal health is a consequence of dietary optimization. Attainment of optimal health rather than prevention of deficiency symptoms is the goal. There can be little doubt that in this respect the requirements for vitamin C are greater than the amount required for the mere prevention of overt or classical scurvy. The recommendation of varying levels of requirement could overcome the controversy. The following is therefore proposed: The lowest level is that value which prevents deficiency symptoms. The second level is valid for healthy populations (< 200 mg/d). This level would take into account needs which differ according to age, sex, physical activity, physiological status (e.g. pregnancy or lactation) and environmental factors such as smoking, pollution and alcohol intake. Finally, a third level should be determined for the prevention of the above-mentioned non-communicable diseases. These diseases are an important cause of disability, resulting in costs of billions of dollars annually in medical costs. Many of the above-mentioned diseases can be prevented by supplementation with vitamin C. Medical costs could thereby also be dramatically reduced.

Topics: Ascorbic Acid; Cardiovascular Diseases; Common Cold; Humans; Neoplasms; Nutritional Requirements; Reference Standards

The effect of vitamin C on the common cold has been the subject of several studies. These studies do not support a considerable decrease in the incidence of the common cold with supplemental vitamin C. However, vitamin C has consistently decreased the duration of cold episodes and the severity of symptoms. The benefits that have been observed in different studies show a large variation and, therefore, the clinical significance may not be clearly inferred from them. The biochemical explanation for the benefits may be based on the antioxidant property of vitamin C. In an infection, phagocytic leucocytes become activated and they produce oxidizing compounds which are released from the cell. By reacting with these oxidants, vitamin C may decrease the inflammatory effects caused by them. Scurvy, which is caused by a deficiency in vitamin C, is mostly attributed to the decreased synthesis of collagen. However, vitamin C also participates in several other reactions, such as the destruction of oxidizing substances. The common cold studies indicate that the amounts of vitamin C which safely protect from scurvy may still be too low to provide an efficient rate for other reactions, possibly antioxidant in nature, in infected people.

Topics: Antioxidants; Ascorbic Acid; Chemotaxis, Leukocyte; Clinical Trials as Topic; Common Cold; Dose-Response Relationship, Drug; Histamine Antagonists; Humans; Neutrophils; Phagocytosis; Time Factors

Topics: Ascorbic Acid; Ascorbic Acid Deficiency; Collagen; Common Cold; Humans; Oxidants

Topics: Adult; Ascorbic Acid; Behavior Therapy; Child; Chronic Disease; Common Cold; Developmental Disabilities; Humans; Minerals; Neoplasms; Orthomolecular Therapy; Risk Factors

Topics: Ascorbic Acid; Common Cold; Double-Blind Method; Humans; Orthomolecular Therapy; Random Allocation

With the expanding knowledge of rhinovirus transmission and rhinovirus chemistry, the outlook for control of infections with these agents has brightened considerably. Although rhinoviruses are probably the world's leading cause of respiratory illness, they are surprisingly reluctant transmitters, infecting only about 50% of susceptibles in family-like settings. Current research suggests that rhinoviruses are spread chiefly by aerosol, rather than by fomites or personal contact. It has been possible to interrupt rhinovirus transmission completely by careful use of virucidal facial tissues, which, presumably, smothered aerosols generated by coughing, sneezing and nose blowing. Accordingly, it may be feasible to control rhinovirus (and perhaps other virus) dissemination by appropriate air handling and filtration systems in combination with careful nasal sanitation. Anti-rhinovirus drug development is also moving forward. Although there are over 100 rhinovirus serotypes, it has been found that most rhinoviruses attach to a single cell receptor by a single binding site on the virus. Also, the structure of the rhinovirus capsid is now known at the atomic level. These two pieces of knowledge about basic viral architecture appear to open new vistas for reasoned synthesis of antiviral drugs, and some promising compounds are now under investigation. Even interferon has been demonstrated useful in a family setting. On several research fronts, there are good grounds for optimism about control of rhinovirus colds.

Topics: Ascorbic Acid; Common Cold; Humans; Interferons; Models, Theoretical; Zinc

Vitamins are a group of organic compounds occurring naturally in food and are necessary for good health. Lack of a vitamin may lead to a specific deficiency syndrome, which may be primary (due to inadequate diet) or secondary (due to malabsorption or to increased metabolic need), and it is rational to use high-dose vitamin supplementation in situations where these clinical conditions exist. However, pharmacological doses of vitamins are claimed to be of value in a wide variety of conditions which have no, or only a superficial, resemblance to the classic vitamin deficiency syndromes. The enormous literature on which these claims are based consists mainly of uncontrolled clinical trials or anecdotal reports. Only a few studies have made use of the techniques of randomisation and double-blinding. Evidence from such studies reveals a beneficial therapeutic effect of vitamin E in intermittent claudication and fibrocystic breast disease and of vitamin C in pressure sores, but the use of vitamin A in acne vulgaris, vitamin E in angina pectoris, hyperlipidaemia and enhancement of athletic capacity, of vitamin C in advanced cancer, and niacin in schizophrenia has been rejected. Evidence is conflicting or inconclusive as to the use of vitamin C in the common cold, asthma and enhancement of athletic capacity, of pantothenic acid in osteoarthritis, and folic acid (folacin) in neural tube defects. Most of the vitamins have been reported to cause adverse effects when ingested in excessive doses. It is therefore worthwhile to consider the risk-benefit ratio before embarking upon the use of high-dose vitamin supplementation for disorders were proof of efficacy is lacking.

Topics: Acne Vulgaris; Ascorbic Acid; Asthma; Cardiovascular Diseases; Common Cold; Fibrocystic Breast Disease; Humans; Neoplasms; Osteoporosis; Vitamin A; Vitamin B Complex; Vitamin D; Vitamin E; Vitamin K; Vitamins

Vitamin C (ascorbic acid) has been known to prevent scurvy for many years. Recent research has shown its importance in lipid and iron metabolism. Vitamin C may also have some effect on the immune system. There is not as yet conclusive evidence that ascorbic acid may cure or prevent colds or cancer. The vitamin has few side effects even when ingested in large quantities. Several methods for analysis of ascorbic acid have been developed. These include titration and fluorometric methods, a ferrozine technique automated for centrifugal analyzers, a high performance liquid chromatography method, and a dip-stick for urine ascorbic acid.

Topics: Aged; Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Chemical Phenomena; Chemistry; Child; Common Cold; Female; Guinea Pigs; Humans; Infant; Lipid Metabolism; Male; Mice; Rabbits; Scurvy

Topics: Adult; Anaphylaxis; Animals; Antibody Formation; Ascorbic Acid; Autoimmune Diseases; Bacterial Infections; Chemotaxis; Common Cold; Female; Humans; Immunity, Cellular; Male; Phagocytes; Phagocytosis; T-Lymphocytes; Virus Diseases

Ascorbic acid in physiological doses is essential for the normal functioning of the human body. Larger doses are required to treat a severe deficiency of vitamin C intake, as in the case of scurvy. Occasionally, massive doses may be required to treat a metabolic defect involving ascorbic acid. There has been some mention of megadose therapy with ascorbic acid for the prevention of colds, the improved healing of wounds and even the treatment of cancer, but no acceptable scientific data have been presented. In fact, in a few instances, such therapy has proved injurious.

Topics: Ascorbic Acid; Chediak-Higashi Syndrome; Common Cold; Female; Humans; Immunity; Infant; Male; Neoplasms; Scurvy; Wound Healing

Of 14 clinical trials of ascorbic acid in the prevention and treatment of the common cold, the data from 8 were considered well enough gathered to be creditable and to warrant combining for an over-all assessment of efficacy. Differences in mean prorated numbers of colds per year and durations of illness were 0.09 plus or minus 0.06 (plus or minus 1 standard error) and 0.11 plus or minus 0.24, respectively, favoring ascorbic acid over the placebo. These are minor and insignificant differences, but in most studies the severity of symptoms was significantly worse in the patients who received the placebo. In one study lasting 9 months, a large number of the volunteers tasted their capsules and correctly guessed what group they were in. All differences in severity and duration were eliminated by analyzing only the data from those who did not know which drug they were taking. Since there are no data on the long-term toxicity of ascorbic acid when given in doses of 1 g or more per day, it is concluded that the minor benefits of questionable validity are not worth the potential risk, no matter how small that might be.

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Evaluation Studies as Topic; Humans; Placebos; Time Factors

Topics: Administration, Oral; Aged; Antigen-Antibody Reactions; Ascorbic Acid; Aspirin; Child; Common Cold; Female; Fenfluramine; Humans; Hypersensitivity; Leukemia; Leukocytes; Lung Neoplasms; Male; Mouth Mucosa; Nutritional Requirements; Scurvy

Topics: Age Factors; Animals; Ascorbic Acid; Child; Common Cold; Female; Guinea Pigs; Health; Humans; Kidney; Leukocytes; Male; Nutritional Requirements; Scurvy; Sex Factors

Topics: Anti-Infective Agents; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Evaluation Studies as Topic; Female; Humans; Male; Placebos; Respiratory Tract Infections; Time Factors

Topics: Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Common Cold; Depression; Guinea Pigs; Humans; Male; Miliaria; Nutritional Requirements; Scurvy; Sjogren's Syndrome; Skin Manifestations; Urinary Bladder Neoplasms

Only four independent double-blind studies have been reported of the effect of ascorbic acid regularly ingested in daily amounts more than 100 mg, in comparison with a placebo, in decreasing the incidence and integrated morbidity of the common cold for subjects exposed to cold viruses in the ordinary way and without colds when the test period began. A statistical analysis of these four studies leads to rejection of the null hypothesis that ascorbic acid has no more protective power than the placebo at the 99.86% level of confidence for the incidence of colds and the 99.9978% level of confidence for the integrated morbidity.

Topics: Administration, Oral; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Female; Humans; Male; Placebos; Statistics as Topic; Time Factors

Topics: Adenoviridae; Adult; Amantadine; Animals; Ascorbic Acid; Cephalosporins; Common Cold; Cricetinae; Enterovirus; Fusidic Acid; Humans; Influenza Vaccines; Interferons; Isoquinolines; Orthomyxoviridae; Orthomyxoviridae Infections; Respirovirus; Rhinovirus; Thiosemicarbazones

Topics: Adenoviridae; Antiviral Agents; Ascorbic Acid; Cold Temperature; Common Cold; Disease Outbreaks; Enterovirus; Humans; Interferons; Orthomyxoviridae; Respirovirus; Rhinovirus; Vaccination; Virus Diseases; Viruses

Topics: Adolescent; Adult; Ascorbic Acid; Common Cold; Humans; Middle Aged

The Republic of Korea (ROK) military has a high incidence of respiratory diseases at training centres. Vitamin C has been reported to reduce the incidence of colds. For the purpose of preventing soldiers' respiratory diseases, this study aimed to investigate whether vitamin C intake can prevent common colds in the ROK Army soldiers.. This was a randomised, placebo-controlled, and double-blind trial of soldiers who enlisted in the Korea Army Training Centre for 30 days from 12 February to 13 March 2018. The study participants were divided into groups (vitamin C vs placebo). The military medical records were searched to determine whether the participants had a common cold. Multiple logistic regression analysis was performed to identify the association between vitamin C intake and diagnosis of common colds. In addition, subgroup analysis on the relationship between vitamin C intake and common cold according to smoking status, training camp and physical rank was conducted.. A total of 1444 participants were included in our study. Of these participants, 695 received vitamin C (6000 mg/day, vitamin C group), while 749 participants received placebo (0 mg/day, placebo group). The vitamin C group had a 0.80-fold lower risk of getting a common cold than did the placebo group. Subgroup analyses showed that this effect was stronger among subjects in camp A, among never smokers and among those in physical rank 3.. Vitamin C intake provides evidence to suggest that reducing the common colds in Korean Army soldiers. Our results may serve as a basis for introducing military healthcare policies that can provide vitamin C supplementation for military personnel in basic military training.

Topics: Ascorbic Acid; Common Cold; Dietary Supplements; Humans; Military Personnel; Republic of Korea

The early indications of vitamin C deficiency are unremarkable (fatigue, malaise, depression) and may manifest as a reduced desire to be physically active; moreover, hypovitaminosis C may be associated with increased cold duration and severity. This study examined the impact of vitamin C on physical activity and respiratory tract infections during the peak of the cold season. Healthy non-smoking adult men (18-35 years; BMI < 34 kg/m2; plasma vitamin C < 45 µmol/L) received either 1000 mg of vitamin C daily (n = 15) or placebo (n = 13) in a randomized, double-blind, eight-week trial. All participants completed the Wisconsin Upper Respiratory Symptom Survey-21 daily and the Godin Leisure-Time Exercise Questionnaire weekly. In the final two weeks of the trial, the physical activity score rose modestly for the vitamin C group vs. placebo after adjusting for baseline values: +39.6% (95% CI [-4.5,83.7]; p = 0.10). The number of participants reporting cold episodes was 7 and 11 for the vitamin C and placebo groups respectively during the eight-week trial (RR = 0.55; 95% CI [0.33,0.94]; p = 0.04) and cold duration was reduced 59% in the vitamin C versus placebo groups (-3.2 days; 95% CI [-7.0,0.6]; p = 0.06). These data suggest measurable health advantages associated with vitamin C supplementation in a population with adequate-to-low vitamin C status.

Topics: Adolescent; Adult; Ascorbic Acid; Ascorbic Acid Deficiency; Body Mass Index; Common Cold; Dietary Supplements; Double-Blind Method; Health Surveys; Healthy Volunteers; Humans; Incidence; Male; Motor Activity; Nutritional Status; Surveys and Questionnaires; Wisconsin; Young Adult

To investigate the relationship between the common cold and vitamin C supplementation.. A double-blind, 5-year randomized controlled trial.. A village in Akita prefecture, one of the regions in Japan with the highest mortality from gastric cancer.. Participants in annual screening programs for circulatory diseases conducted under the National Health and Welfare Services Law for the Aged, and diagnosed as having atrophic gastritis. Of the 439 eligible subjects, 144 and 161 were assigned to receive 50 or 500 mg of vitamin C, respectively, after protocol amendment. During the supplementation phase, 61 dropped out, and 244 completed the trial.. Daily vitamin C supplementation of 50 mg (low-dose group) or 500 mg (high-dose group).. Total number of common colds (per 1000 person-months) was 21.3 and 17.1 for the low- and high-dose groups, respectively. After adjustment for several factors, the relative risks (95% confidence interval (CI)) of suffering from a common cold three or more times during the survey period was 0.34 (0.12-0.97) for the high-dose group. No apparent reduction was seen for the severity and duration of the common cold.. A randomized, controlled 5-year trial suggests that vitamin C supplementation significantly reduces the frequency of the common cold but had no apparent effect on the duration or severity of the common cold. However, considering several limitations due to protocol amendment, the findings should be interpreted with caution.

Topics: Adult; Aged; Antioxidants; Ascorbic Acid; Common Cold; Confidence Intervals; Dietary Supplements; Dose-Response Relationship, Drug; Double-Blind Method; Female; Humans; Japan; Longitudinal Studies; Male; Middle Aged; Risk Factors; Severity of Illness Index; Time Factors

The aim of the present trial was to evaluate the efficacy of a combined product in the treatment of common cold and to examine the contribution of the separate components. In the published literature there is conflicting data on the efficacy of agents used in the treatment of common cold, especially when given in drug combinations.. A prospective, randomized, double-blind, multicenter, 4-arm, controlled trial was carried out in 1,167 patients with common cold treated with one of the following medications: Grippostad-C, a combination of acetaminophen, caffeine, chlorpheniramine and ascorbic acid (verum), ascorbic acid (control), chlorpheniramine and ascorbic acid (reference 1), as well as acetaminophen, caffeine, and ascorbic acid (reference 2). A score of common cold symptoms (headache, throat pain, extremities and joint pain, cough, blocked nose, and disturbances of sleep quality) was the primary outcome. The test drug was first compared with the control using a hierarchic test strategy, then with reference 1, followed by reference 2 with the aim of proving superiority.. A clinically relevant and statistically significant difference was demonstrated at each level of the hierarchy. Grippostad-C was significantly superior to all other treatment groups, the combination of acetaminophen, caffeine, and ascorbic acid was significantly superior to the control, and the combination of chlorpheniramine and ascorbic acid was not statistically different from the control.. The efficacy of Grippostad-C for the treatment of common cold was proven. The findings demonstrate that the combination is superior to each of its separate components and each of the components has its own distinctive contribution to the efficacy of the combination product.

Topics: Acetaminophen; Adolescent; Adult; Aged; Analgesics, Non-Narcotic; Ascorbic Acid; Caffeine; Chlorpheniramine; Common Cold; Double-Blind Method; Drug Combinations; Histamine H1 Antagonists; Humans; Middle Aged; Phosphodiesterase Inhibitors; Prospective Studies; Treatment Outcome

To determine the effect of large doses of vitamin C in the treatment of the common cold.. Double-blind, randomised clinical trial with four intervention arms: vitamin C at daily doses of 0.03g ("placebo"), 1 g, 3g, or 3g with additives ("Bio-C") taken at onset of a cold and for the following two days.. 400 healthy volunteers were recruited from staff and students of the Australian National University, Canberra, ACT, between May 1998 and November 1999. The trial continued for 18 months.. Participants were instructed to commence medication when they had experienced early symptoms of a cold for four hours, and to record daily their symptoms, severity, doctor visits and use of other medications.. Duration of symptoms and cold episodes; cumulative symptom severity scores after 7, 14 and 28 days; doctor visits; and whether participants guessed which medication they were taking.. 149 participants returned records for 184 cold episodes. No significant differences were observed in any measure of cold duration or severity between the four medication groups. Although differences were not significant, the placebo group had the shortest duration of nasal, systemic and overall symptoms, and the lowest mean severity score at 14 days, and the second lowest at 7 and 28 days.. Doses of vitamin C in excess of 1 g daily taken shortly after onset of a cold did not reduce the duration or severity of cold symptoms in healthy adult volunteers when compared with a vitamin C dose less than the minimum recommended daily intake.

Topics: Adult; Analysis of Variance; Ascorbic Acid; Australia; Common Cold; Confidence Intervals; Dose-Response Relationship, Drug; Double-Blind Method; Drug Administration Schedule; Female; Follow-Up Studies; Humans; Male; Middle Aged; Reference Values; Severity of Illness Index; Treatment Outcome

An ever increasing demand to evaluate the effect of dietary supplements on specific health conditions by use of a "significant scientific" standard has prompted the publication of this study.. To study the effect of megadose Vitamin C in preventing and relieving cold and flu symptoms in a test group compared with a control group.. Prospective, controlled study of students in a technical training facility.. A total of 463 students ranging in age from 18 to 32 years made up the control group. A total of 252 students ranging in age from 18 to 30 years made up the experimental or test group.. Investigators tracked the number of reports of cold and flu symptoms among the 1991 test population of the facility compared with the reports of like symptoms among the 1990 control population. Those in the control population reporting symptoms were treated with pain relievers and decongestants, whereas those in the test population reporting symptoms were treated with hourly doses of 1000 mg of Vitamin C for the first 6 hours and then 3 times daily thereafter. Those not reporting symptoms in the test group were also administered 1000-mg doses 3 times daily.. Overall, reported flu and cold symptoms in the test group decreased 85% compared with the control group after the administration of megadose Vitamin C.. Vitamin C in megadoses administered before or after the appearance of cold and flu symptoms relieved and prevented the symptoms in the test population compared with the control group.

Topics: Adolescent; Adult; Ascorbic Acid; Common Cold; Drug Administration Schedule; Female; Humans; Incidence; Influenza, Human; Male

A rhinomanometric technique was used to evaluate the nasal decongestant effect of a single dose of Day Nurse over a 4-hour post-dosing period in human volunteers suffering from nasal congestion due to a common cold. A significant improvement in nasal congestion was obtained at the 1 hour, 2 hour, 3 hour and 4 hour post-dosing interval, from initial values compared to a placebo group. The study therefore demonstrated by an objective technique that Day Nurse provides relief of nasal congestion and related symptoms in cold sufferers.

Topics: Acetaminophen; Adolescent; Adult; Aged; Ascorbic Acid; Codeine; Common Cold; Dextromethorphan; Double-Blind Method; Drug Combinations; Female; Humans; Levorphanol; Male; Manometry; Middle Aged; Multi-Ingredient Cold, Flu, and Allergy Medications; Nose; Phenylpropanolamine; Pressure; Pseudoephedrine; Random Allocation; Time Factors

Topics: Adolescent; Adult; Aged; Ascorbic Acid; Blood Chemical Analysis; Clinical Trials as Topic; Common Cold; Diseases in Twins; Female; Humans; Middle Aged; Placebos; Pregnancy; Twins, Monozygotic

We analysed self-reported cold data for 95 pairs of identical twins who took part in a double-blind trial of vitamin C tablets. One member of each twin pair took vitamin C and the other took a well matched placebo each day for 100 days. Vitamin C had no significant effect except for shortening the average duration of cold episodes by 19%.

Topics: Adolescent; Adult; Aged; Ascorbic Acid; Child; Clinical Trials as Topic; Common Cold; Diseases in Twins; Double-Blind Method; Female; Humans; Male; Middle Aged; Pregnancy; Time Factors; Twins, Monozygotic

Self-reported cold data have been analyzed for 95 pairs of identical twins aged 14-64 who took part in a double-blind trial of vitamin C tablets. One member of each twin pair took a tablet containing 1 g vitamin C and the other took a well-matched placebo each day for 100 days. In the total sample there was no effect of vitamin C in preventing colds. However, subdivision of the data showed a significant preventive effect of the placebo in the 51 pairs living together and an equal and opposite preventive effect of the vitamin C in the 44 pairs living apart. The placebo effect in the pairs living together may be attributed to the large proportion who wrongly perceived which treatment they were taking. The reduction of colds in the vitamin C group of the pairs living apart was about 20%. There were significant correlations between cold symptoms reported and the personality trait of neuroticism. No side effects of substantive changes in serum biochemistry could be attributed to the vitamin C dose.

Topics: Adolescent; Adult; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Diseases in Twins; Double-Blind Method; Female; Humans; Male; Middle Aged; Pregnancy; Twins, Monozygotic

A prospective, randomized, double-blind study was carried out to determine whether vitamin C prophylaxis, 2.0 g/day, vs placebo prophylaxis would reduce the incidence or morbidity of the common cold and other respiratory illnesses in 674 marine recruits during an eight-week period. Whole-blood ascorbic acid levels measured six weeks after initiation of the study were significantly higher in the vitamin C group. There was no difference between the two groups in the incidence or duration of colds. The vitamin C group rated their colds as being less severe, but this was not reflected in different symptom complexes or in fewer sick-call visits or training days lost. This study and the literature do not support the prophylactic use of vitamin C to prevent the common cold.

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Double-Blind Method; Drug Evaluation; Humans; Male; Naval Medicine

Large-scale clinical trials of the effect of vitamin C on the common cold conducted since Pauling's pronouncement on its efficacy in 1970 have produced conflicting results. Benefits shown have been modest, and positive findings have not been reproducible. Reported benefits probably are due to statistical artifact, minor vitamin-induced physiologic changes, the placebo effect, or a combination of these.

Topics: Adolescent; Ascorbic Acid; Child; Clinical Trials as Topic; Common Cold; Dose-Response Relationship, Drug; Double-Blind Method; Drug Evaluation; Female; Humans; Male; Placebos

A controlled study was made of the effects of natural orange juice, synthetic orange juice, and placebo in the prevention of the common cold; both natural and synthetic orange juices contained 80 mg of ascorbic acid daily. Three-hundred sixty-two healthy normal young adult volunteers, ages 17 to 25 years, were studied for 72 days with 97% of participants completing the trial. There was a 14 to 21% reduction in total symptoms due to the common cold in the supplemented groups that was statistically significant (P less than 0.05). Ascorbic acid supplementation also increased the number of "episode-free" subjects. However, the clinical usefulness of the results does not support prophylactic ascorbic acid supplements in the well-nourished adult. The results in this study with both natural and synthetic orange juice of physiological content of ascorbic acid, are similar to those obtained using a "megadose" of ascorbic acid.

Topics: Adolescent; Adult; Ascorbic Acid; Common Cold; Female; Flavonoids; Humans; Male; Sex Factors; Time Factors

Topics: Adult; Ascorbic Acid; Aspirin; Clinical Trials as Topic; Common Cold; Female; Humans; Leukocytes; Male; Time Factors

Topics: Adolescent; Amino Acids; Ascorbic Acid; Child; Cholesterol; Common Cold; Dose-Response Relationship, Drug; Double-Blind Method; Female; Growth; Humans; Intelligence; Male; Motor Skills; Pregnancy; Sex Factors; Twins; Twins, Monozygotic

Three different dosages of vitamin C, dependent on body weight, were administered to 44 school-aged monozygotic twins for five months using a double-blind, co-twin control study design. The mothers recorded daily observations of cold symptoms, and multiple biochemical, anthropometric, and psychological measurements were made at the beginning and end of the study. Paired comparisons showed no significant overall treatment effect on cold symptoms, but the response was not uniform in all sub-groups. Treated girls in the youngest two groups had significantly shorter and less severe illness episodes, and an effect on severity was also observed in the youngest group of boys. The seven treated twins in the latter group also grew an average of 1.3 cm more than their untreated co-twins during the five-minth period of the study.

Topics: Adolescent; Ascorbic Acid; Child; Clinical Trials as Topic; Common Cold; Diseases in Twins; Female; Growth; Humans; Male; Mental Processes; Motor Skills; Placebos; Pregnancy; Twins, Monozygotic

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Female; Humans; Male; Sex Factors; Smoking

A randomised controlled trial was carried out to study the effect of 10 g of ascorbic acid taken during the first 2 1/2 days on the symptoms of the common cold. Altogether 1524 volunteers were recruited from a number of working groups in different parts of the country; 482 developed colds. There was no evidence that upper respiratory or general constitutional symptoms were alleviated by ascorbic acid. Among the men who had any colds at all, significantly fewer on active than on placebo treatment had two or more colds; however, this effect was not seen in women. Ascorbic acid is of no value in the treatment of the common cold; its preventive effect, if any, is not such as to justify advising its general use as a prophylactic measure.

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Female; Humans; Male; Recurrence; United Kingdom

The combination of a regular daily supplement of vitamin C with extra dosage at the time of illness has been shown to reduce the disability due to common colds and other winter illness, but we have seen little effect on frequency of infections, sense of (well-being), or levels of serum cholesterol. The variable results that have been obtained from some other trials of vitamin C may be due in part to variation in the initial nutritional state of the subjects, with the greatest effects to be expected where there is most room for improvement. Because of the great variation in individual susceptibility to infection large numbers of subjects are required in these trials and they must be strictly double-blind. Although we have seen no clear evidence of harmful side-effects, occasional sensitivity to large doses of vitamin C cannot be ruled out, and the withdrawal depression of blood levels could conceivably interfere with a patient's ability to handle stress.

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Humans; Orthomolecular Therapy

During 7 weeks in the spring of 1973 a double-blind pilot study on 172 children in the age group 8-9 was carried out to test the possible effect of 1000 mg vitamin C daily as a prophylactic agent against common colds. During the autumn of 1973, a main study was carried out on 642 children of the same age. The investigations had the same pattern and lasted for 3 months. Both studies have been processed on the same principles. The results were somewhat divergent but, like previously published studies on children, seemed to indicate that the duration and severity of the cold were reduced while, on the other hand, the incidence remained unaltered or indeed increased. The total number of days of upper respiratory tract infection was smaller for the vitamin C group only in the pilot study (not in the main study). No proven biochemical effects were obtained. Preventive treatment of healthy children with vitamin C in large doses this had no definitely proved effect against colds.

Topics: Adolescent; Age Factors; Ascorbic Acid; Child; Common Cold; Drug Evaluation; Female; Humans; Male; Respiratory Tract Infections

Topics: Ascorbic Acid; Benzhydryl Compounds; Clinical Trials as Topic; Common Cold; Delayed-Action Preparations; Histamine H1 Antagonists; Humans; Piperidines

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Humans; Placebos

To evaluate earlier observations, including our own, showing usefulness of vitamin C for managing the common cold, we performed a double-blind trial of vitamin C versus placebo in 868 children. There was no difference in number becoming ill (133 versus 129), number of episodes (166 versus 159) or mean illness duration (5.5 versus 5.8 days) between the groups. Children receiving vitamin C had fewer throat cultures yielding beta-hemolytic streptococcus (six versus 13, P less than 0.10), but no difference in overall complicated illness rate (24 versus 25). Plasma ascorbic acid levels were higher in the vitamin group 24 to 26 hours after supplementation (1.28 versus 1.04 mg per 100 ml, P less than 0.01). Children with high plasma ascorbic acid concentrations had longer mean illness (6.8 versus 4.0 days, P less than 0.05) than those with low levels. Vitamin C does not seem to be an effective prophylactic or therapeutic agent for upper respiratory illness.

Topics: Acute Disease; Adolescent; Age Factors; Arizona; Ascorbic Acid; Child; Clinical Trials as Topic; Common Cold; Female; Humans; Indians, North American; Male; Otitis Media; Placebos; Respiratory Tract Infections; Time Factors

A randomized controlled trial of the effect of 1 g ascorbic acid per day in the prevention of the common cold was conducted on 688 adult women. There is evidence of a small reduction by vitamin C in the mean number of chest colds, but no evidence of any effect on simple colds. The existence of a subgroup of vulnerable women in the community who benefit from vitamin C was considered but further examination of the data gives no support to this conclusion.

Topics: Adult; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Cough; Female; Humans; Placebos; Time Factors

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Dose-Response Relationship, Drug; Humans

Topics: Ascorbic Acid; Bioethical Issues; Child; Child Health Services; Clinical Trials as Topic; Common Cold; Compensation and Redress; Control Groups; Coronary Care Units; Coronary Disease; Disclosure; Epidemiologic Methods; Ethics Committees, Clinical; Ethics Committees, Research; Ethics, Medical; Federal Government; Female; Glomerulonephritis; Government Regulation; Human Experimentation; Humans; Informed Consent; Insurance, Liability; Jurisprudence; Male; Maternal Health Services; Moral Obligations; Nontherapeutic Human Experimentation; Penicillin G Benzathine; Placebos; Professional Staff Committees; Respiratory Tract Infections; Rheumatic Fever; Risk Assessment; Streptococcal Infections; Therapeutic Human Experimentation; United States; Withholding Treatment

Topics: Ascorbic Acid; Common Cold; Double-Blind Method; Female; Humans; Male; Time Factors

Three hundred eleven employees of the National Institutes of Health volunteered to take 1 gm of ascorbic acid or lactose placebo in capsules three times a day for nine months. At the onset of a cold, the volunteers were given an additional 3 gm daily of either a placebo or ascorbic acid. One hundred ninety volunteers completed the study. Dropouts were defined as those who missed at least one month of drug ingestion. They represented 44% of the placebo group and 34% of those taking ascorbic acid. Analysis of these data showed that ascorbic acid had at best only a minor influence on the duration and severity of colds, and that the effects demonstrated might be explained equally well by a break in the double blind.

Topics: Adult; Ascorbic Acid; Autosuggestion; Clinical Trials as Topic; Common Cold; Female; Humans; Male; Middle Aged; Placebos; Rhinovirus; Seasons; Surveys and Questionnaires

We reviewed the clinical data relating to the efficacy and safety of pharmacologic doses of ascorbic acid in the prevention and treatment of the common cold. Although one study tentatively supports the hypothesis that such doses of ascorbic acid may be efficacious, a second study by the same group did not confirm the significant findings, and no clear, reproducible pattern of efficacy has emerged from the review of all the evidence. Similarly, there is currently little adequate evidence on either the presence or the absence of serious adverse reactions to such doses of ascorbic acid, although many such reactions have been hypothesized. The unrestricted use of ascorbic acid for these purposes cannot be advocated on the basis of the evidence currently available.

Topics: Administration, Oral; Animals; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Digestive System; Drug Interactions; Female; Fetus; Flavonoids; Guinea Pigs; Humans; Hyperglycemia; Injections, Intravenous; Injections, Subcutaneous; Male; Maternal-Fetal Exchange; Placebos; Pregnancy; Rats; Time Factors; Urinary Calculi

After their random -llocation to one of three treatment aroups, 622 volunteers received either vitamin C or placebo in a maintenance dose of 500 mg once weekly and a therapeutic dose of 1500 mg daily on the 1st day and 1000 mg on the next 4 days of any illness. Two forms of vitamin C were employed: a sustained-release capsule containing ascorbic acid and a regular tabet containing a mixture of sodium and calcium ascorbate. In the 448 subjects who completed an average of 15 weeks in the study of total of 635 episodes of illness were recroded. Respiratory symptoms were recorded on at least 1 day in 92 per cent of these episodes. There were no consistent or significant differences in the sickness experience of the subjects receiving the sustained-release vitamin capsules compared to those receiving the vitamin tablets, but subjects in both vitamin groups experienced less severe illness than subjects in the placebo group, with approximately 25 per cent fewer days spent indoors because of the illness (P smaller than 0.05). These results are compatible with the belief that supplementary vitamin C can reduce the burden of winter illness, but the intake need not be as high as has sometimes been claimed.

Topics: Adolescent; Adult; Aged; Ascorbic Acid; Calcium; Clinical Trials as Topic; Common Cold; Drug Combinations; Female; Humans; Male; Middle Aged; Ontario; Placebos; Respiratory Tract Infections; Seasons; Sodium; Tablets; Time Factors

Of 14 clinical trials of ascorbic acid in the prevention and treatment of the common cold, the data from 8 were considered well enough gathered to be creditable and to warrant combining for an over-all assessment of efficacy. Differences in mean prorated numbers of colds per year and durations of illness were 0.09 plus or minus 0.06 (plus or minus 1 standard error) and 0.11 plus or minus 0.24, respectively, favoring ascorbic acid over the placebo. These are minor and insignificant differences, but in most studies the severity of symptoms was significantly worse in the patients who received the placebo. In one study lasting 9 months, a large number of the volunteers tasted their capsules and correctly guessed what group they were in. All differences in severity and duration were eliminated by analyzing only the data from those who did not know which drug they were taking. Since there are no data on the long-term toxicity of ascorbic acid when given in doses of 1 g or more per day, it is concluded that the minor benefits of questionable validity are not worth the potential risk, no matter how small that might be.

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Evaluation Studies as Topic; Humans; Placebos; Time Factors

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Female; Food Additives; Health Surveys; Humans; Male; Sex Factors; Structure-Activity Relationship

In a survey of double-bind design, 3 groups of approximately 70 student volunteers took 1 g L-ascorbic acid, 1 g D-isoascorbic acid, or placebo tablets every day for 15 weeks and the incidence and duration of colds were recorded. The group taking D-isoascrobic acid suffered 34% fewer colds than the other two groups; the results were also analyzed in relation to the sex and smoking habits of the volunteers. The rationale for investigating D-isoascorbic acid, an isomer of L-ascorbic acid which has limited antiscorbutic activity, is discussed.

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Female; Humans; Isomerism; Male; Placebos; Sex Factors; Smoking; Structure-Activity Relationship

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Dose-Response Relationship, Drug; Humans; Placebos; Time Factors

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Humans; Placebos; Psychology; Statistics as Topic; Taste; Time Factors

Topics: Adolescent; Age Factors; Arizona; Ascorbic Acid; Child; Clinical Trials as Topic; Common Cold; Humans; Indians, North American; Placebos

Topics: Ascorbic Acid; Child; Clinical Trials as Topic; Common Cold; Dose-Response Relationship, Drug; Female; Humans; Leukocytes; Male; Placebos; Saliva; Sex Factors; Tongue

Topics: Adult; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Diet; Female; Humans; Male

Topics: Adenoviridae Infections; Ascorbic Acid; Citrates; Clinical Trials as Topic; Common Cold; Humans; Influenza, Human; Leukocytes; Placebos; Respiratory Tract Infections; Virus Diseases

Topics: Adolescent; Adult; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Female; Humans; Male; Middle Aged

Between December 1972 and February 1973, 2349 volunteers participated in a double-blind trial to assess the effect of large doses of vitamin C on the incidence and severity of winter illness. In addition, records were kept but no tablets taken during March. Subjects were randomly allocated to eight treatment regimens: three prophylactic-only (daily dose 0.25, 1 or 2 g), two therapeutic-only (4 or 8 g on the first day of illness), one combination (1 g daily and 4 g on the first day of illness), and two all-placebo. None of the groups receiving vitamin C showed a difference in sickness experience that was statistically significant from that of the placebo groups, but the results obtained were compatible with an effect of small magnitude from both the prophylactic and therapeutic regimens, and an effect of somewhat greater magnitude from the combination regimen. The combination regimen was associated more with a reduction in severity than frequency of illness, although the extra dosage was limited to the first day of illness. In spite of the eightfold range in daily dose, the three prophylactic-only regimens showed no evidence of a dose-related effect, but the 8 g therapeutic dose was associated with less illness than the 4 g therapeutic dose. There was no evidence of side effects from the 1 and 2 g prophylactic doses of vitamin C, and no evidence of a rebound increase in illness during the month following withdrawal of the daily vitamin supplements. On the basis of this and other studies it is suggested that the optimum daily dose of vitamin C is less than 250 mg, except possibly at the time of acute illness, when a larger daily intake may be beneficial.

Topics: Administration, Oral; Adult; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Dose-Response Relationship, Drug; Female; Humans; Male; Patient Dropouts; Placebos; Respiratory Tract Diseases; Seasons; Tablets; Time Factors

Topics: Adult; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Drug Evaluation; Female; Humans; Male; Placebos

Topics: Animals; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Guinea Pigs; Humans; Placebos

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Drug Evaluation; Humans; Placebos

Topics: Age Factors; Ascorbic Acid; Child; Clinical Trials as Topic; Common Cold; Evaluation Studies as Topic; Female; Humans; Leukocytes; Male; Placebos; Sex Factors

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Female; Humans; Male; Placebos; Sex Factors

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Female; Humans; Male; Placebos

Topics: Adult; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Humans; Male; Middle Aged; Placebos; Rhinovirus

Topics: Ascorbic Acid; Bacterial Infections; Clinical Trials as Topic; Common Cold; Humans; Leukocytes; Placebos

Topics: Ascorbic Acid; Child; Clinical Trials as Topic; Common Cold; Dose-Response Relationship, Drug; Female; Humans; Male; Placebos; Research Design; Sex Factors; Statistics as Topic; Time Factors

Topics: Ascorbic Acid; Child; Clinical Trials as Topic; Common Cold; Dose-Response Relationship, Drug; Female; Humans; Male; Placebos; Sex Factors

Topics: Anti-Infective Agents; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Evaluation Studies as Topic; Female; Humans; Male; Placebos; Respiratory Tract Infections; Time Factors

Topics: Adaptation, Physiological; Ascorbic Acid; Common Cold; Humans; Scurvy

Topics: Ascorbic Acid; Common Cold; Humans; Placebos; Rhinovirus

Topics: Adult; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Humans; Male; Middle Aged; Placebos

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Evaluation Studies as Topic; Humans; Male; Placebos

A large scale double-blind trial was conducted to test the claim that the intake of one gram of vitamin C per day substantially reduces the frequency and duration of "colds". It was found that in terms of the average number of colds and days of sickness per subject the vitamin group experienced less illness than the placebo group, but the differences were smaller than have been claimed and were statistically not significant. However, there was a statistically significant difference (P <0.05) between the two groups in the number of subjects who remained free of illness throughout the study period. Furthermore the subjects receiving the vitamin experienced approximately 30% fewer total days of disability (confined to the house or off work) than those receiving the placebo, and this difference was statistically highly significant (P <0.001). The reduction in disability appeared to be due to a lower incidence of constitutional symptoms such as chills and severe malaise, and was seen in all types of acute illness, including those which did not involve the upper respiratory tract.

Topics: Adolescent; Adult; Aged; Ascorbic Acid; Child; Common Cold; Evaluation Studies as Topic; Female; Humans; Male; Middle Aged; Occupations; Placebos; Smoking

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Complementary Therapies; Famous Persons; Humans; Propaganda; United States

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Humans; Nutritional Requirements

Topics: Adult; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Humans; Placebos; Statistics as Topic

Only four independent double-blind studies have been reported of the effect of ascorbic acid regularly ingested in daily amounts more than 100 mg, in comparison with a placebo, in decreasing the incidence and integrated morbidity of the common cold for subjects exposed to cold viruses in the ordinary way and without colds when the test period began. A statistical analysis of these four studies leads to rejection of the null hypothesis that ascorbic acid has no more protective power than the placebo at the 99.86% level of confidence for the incidence of colds and the 99.9978% level of confidence for the integrated morbidity.

Topics: Administration, Oral; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Female; Humans; Male; Placebos; Statistics as Topic; Time Factors

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Humans; Placebos

Topics: Animals; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Diarrhea; Evaluation Studies as Topic; Placebos

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Humans

Topics: Adolescent; Adult; Aged; Ascorbic Acid; Child; Child, Preschool; Clinical Trials as Topic; Common Cold; Female; Humans; Infant; Infant, Newborn; Male; Middle Aged; Placebos

Topics: Adolescent; Adult; Aged; Ascorbic Acid; Child; Clinical Trials as Topic; Common Cold; Humans; Middle Aged

Topics: Adenoviridae; Adolescent; Adult; Animals; Ascorbic Acid; Common Cold; Culture Techniques; Enterovirus; Enterovirus B, Human; Female; Humans; Male; Mice; Middle Aged; Orthomyxoviridae; Poliovirus; Respiratory Syncytial Viruses; Respirovirus; Rhinovirus; Simplexvirus

Topics: Ascorbic Acid; Common Cold; COVID-19; Humans; SARS-CoV-2; Vitamins

Topics: Ascorbic Acid; Child; Common Cold; Humans

Acute upper respiratory tract infections are extremely common in adults and children, but only a few safe and effective treatments are available. Patients typically present with nasal congestion, rhinorrhea, sore throat, cough, general malaise, and/or low-grade fever. Informing patients about the self-limited nature of the common cold can help manage expectations, limit antibiotic use, and avoid over-the-counter purchases that may not help. Treatments with proven effectiveness for cold symptoms in adults include over-the-counter analgesics, zinc, nasal decongestants with or without antihistamines, and ipratropium for cough. Lower-quality evidence suggests that Lactobacillus casei may be beneficial in older adults. The only established safe and effective treatments for children are acetylcysteine, honey (for children one year and older), nasal saline irrigation, intranasal ipratropium, and topical application of ointment containing camphor, menthol, and eucalyptus oils. Over-the-counter cold medications should not be used in children younger than four years. Counseling patients about the importance of good hand hygiene is the best way to prevent transmission of cold viruses.

Topics: Adult; Ascorbic Acid; Child; Common Cold; Echinacea; Fluid Therapy; Humans; Nasal Decongestants; Nonprescription Drugs; Patient Education as Topic

Topics: Adult; Ascorbic Acid; Common Cold; Echinacea; Fluid Therapy; Humans; Nasal Decongestants; Nonprescription Drugs; Patient Education as Topic

Topics: Ascorbic Acid; Child; Child Welfare; Common Cold; Echinacea; Fluid Therapy; Humans; Nasal Decongestants; Nonprescription Drugs; Patient Education as Topic

Topics: Ascorbic Acid; Child; Common Cold; Humans

Topics: Antioxidants; Ascorbic Acid; Common Cold; Diet; Food Preferences; Fruit; Health Behavior; Humans; Vegetables

Topics: Ascorbic Acid; Common Cold; Complementary Therapies; Drug Therapy, Combination; Humans; Materia Medica; Phytotherapy

Topics: Ascorbic Acid; Common Cold; Garlic; Humans; Medicine, Traditional; Steam; Treatment Outcome; Zinc

Topics: Ascorbic Acid; Common Cold; Dietary Supplements; Humans; Randomized Controlled Trials as Topic

Topics: Adult; Ascorbic Acid; Child; Common Cold; Dietary Supplements; Female; Humans; Male; Treatment Outcome

Topics: Ascorbic Acid; Common Cold; Controlled Clinical Trials as Topic; Humans; Severity of Illness Index; Vitamins

Topics: Ascorbic Acid; Common Cold; Humans; Vitamins

Topics: Ascorbic Acid; Common Cold; Dietary Supplements; Humans; Zinc

Topics: Adult; Ascorbic Acid; Child; Common Cold; Drug Administration Schedule; Humans; Vitamins

Little is known about professionals' knowledge and attitudes regarding the clinical significance of treatments for common cold (upper respiratory infection, presumed viral).. We surveyed university-associated family physicians and published common cold researchers ("experts") regarding evidence-of-benefit and magnitude-of-benefit for 8 treatments: antihistamine, oral decongestant, nasal decongestant, nasal steroid, zinc lozenge, zinc nasal spray, vitamin C, and the herbal echinacea.. Responding family physicians (N = 89) and experts (N = 45) agreed that cold remedies do not reduce illness duration. There was substantial disagreement, however, regarding the evidence for severity reduction. Decongestants were rated most favorably. Alternative therapies (zinc, vitamin C, and echinacea) were rated approximately as favorably as the other conventional treatments (antihistamine, decongestant, nasal steroid). Published experts and family physicians responded similarly, as did men (N = 84) and women (N = 49). Older respondents (age > or = 45; N = 67) were less likely to rate treatments as justifiable than were their younger counterparts (P-values ranged from 0.001 to 0.078).. Family physicians and common cold experts tend to agree that available cold remedies offer limited benefit, with conventional and alternative therapies rated similarly. Substantive disagreements exist, however, regarding strength-of-evidence, and over whether current evidence justifies treatment. Older professionals appear more skeptical.

Topics: Adult; Age Factors; Ascorbic Acid; Common Cold; Echinacea; Evidence-Based Medicine; Health Knowledge, Attitudes, Practice; Histamine H1 Antagonists; Humans; Middle Aged; Nasal Decongestants; Physicians, Family; Randomized Controlled Trials as Topic; Steroids; Surveys and Questionnaires; Zinc

Topics: Amino Acids; Antioxidants; Ascorbic Acid; Common Cold; Complementary Therapies; Consumer Product Safety; Electrolytes; Humans; Plant Preparations

Topics: Arizona; Ascorbic Acid; Child; Common Cold; History, 20th Century; Humans; Indians, North American; Research Design

Topics: Ascorbic Acid; Common Cold; Communication; Humans; Models, Biological; Vitamins

Topics: Administration, Oral; Ascorbic Acid; Common Cold; Humans; Vitamins

Topics: Ascorbic Acid; Common Cold; Controlled Clinical Trials as Topic; Humans; Placebos; Time Factors

Topics: Ascorbic Acid; Common Cold; Consumer Product Safety; Dietary Supplements; Drug Contamination; Echinacea; Humans; Lead; Plant Preparations; United States; Zinc

Topics: Ascorbic Acid; Common Cold; Feeding Behavior; Fruit; Humans; Vegetables

Topics: Antiviral Agents; Ascorbic Acid; Common Cold; Conflict of Interest; Drug Industry; Echinacea; Humans; Phytotherapy; Treatment Outcome

Topics: Ascorbic Acid; Common Cold; Dietary Supplements; Food; Humans; Treatment Failure; Zinc

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Humans; Placebo Effect

We evaluated the role of dietary vitamin C, vitamin E, and beta-carotene, as well as long-term vitamin E and beta-carotene supplementation, on the incidence of common cold episodes. A cohort of 21,796 male smokers was drawn from the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study, which examined the effects of 50 mg per day vitamin E and 20 mg per day beta-carotene on lung cancer. Diet and background characteristics were recorded at the study entry, and subjects were queried three times per year on common cold episodes. We modeled the total number of colds during a 4-year follow-up period with Poisson regression, adjusting for covariates of dietary intake. Dietary vitamins C and E and beta-carotene had no meaningful association with common cold incidence. Long-term vitamin E and beta-carotene supplementation had no overall effect.Among subjects 65 years of age or older, the incidence of colds was slightly lower in the vitamin E group (RR = 0.95; 95% CI = 0.90-1.00); this reduction was greatest among older city dwellers who smoked fewer than 15 cigarettes per day (RR = 0.72; 95% CI = 0.62-0.83). In this male smoking population, vitamins C and E and beta-carotene had no overall association with the incidence of common cold episodes.

Topics: Aged; Ascorbic Acid; beta Carotene; Cohort Studies; Common Cold; Diet Surveys; Health Status Indicators; Humans; Incidence; Male; Middle Aged; Poisson Distribution; Risk Factors; Smoking; Vitamin E

To examine whether intake of vitamin C and zinc is associated with a decrease in the risk of a common cold, we analyzed data from a cohort study carried out in a population of 4,272 faculty and staff from five Spanish universities. Participants were 21-65 years of age, were full-time workers at those universities, and did not have antecedents of asthma or chronic obstructive pulmonary disease. Daily intake of vitamin C and zinc was assessed at baseline by means of a food frequency questionnaire of which the validity and reproducibility were determined in a sample of the population. Subjects were traced for 1 year to detect episodes of common cold, the diagnosis of which was based on symptoms and was validated by additional clinical signs. We detected 1,667 cases of common cold in 79,240 person-weeks of follow-up. Intake of vitamin C and zinc was not related to the occurrence of common cold. Compared with the first quartile of intake, women in the fourth quartile of vitamin C intake showed an adjusted incidence rate ratio of 1.0 (95% CI = 0.7-1.3), and for zinc intake this figure was 1.1 (95% CI = 0.8-1.5). The incidence rate ratios for men in the fourth quartile were 1.1 (95% CI = 0.8-1.4) for vitamin C and 1.3 (95% CI = 0.9-1.8) for zinc.

Topics: Adult; Aged; Ascorbic Acid; Cohort Studies; Common Cold; Diet Surveys; Female; Humans; Incidence; Male; Middle Aged; Poisson Distribution; Risk Factors; Spain; Zinc

Topics: Ascorbic Acid; Common Cold; Humans; Randomized Controlled Trials as Topic; Research Design

Placebo-controlled trials have shown that vitamin C supplementation decreases the duration and severity of common cold infections. However, the magnitude of the benefit has substantially varied, hampering conclusions about the clinical significance of the vitamin. In this paper, 23 studies with regular vitamin C supplementation (> or = 1 g/day) were analyzed to find out factors that may explain some part of the variation in the results. It was found that on average, vitamin C produces greater benefit for children than for adults. The dose may also affect the magnitude of the benefit, there being on average greater benefit from > or = 2 g/day compared to 1 g/day of the vitamin. In five studies with adults administered 1 g/day of vitamin C, the median decrease in cold duration was only 6%, whereas in two studies with children administered 2 g/day the median decrease was four times higher, 26%. The trials analyzed in this work used regular vitamin C supplementation, but it is conceivable that therapeutic supplementation starting early at the onset of the cold episode could produce comparable benefits. Since few trials have examined the effects of therapeutic supplementation and their results have been variable, further therapeutic trials are required to examine the role of vitamin C in the treatment of colds.

Topics: Adult; Ascorbic Acid; Child; Common Cold; Controlled Clinical Trials as Topic; Dose-Response Relationship, Drug; Humans; Time Factors

Topics: Ascorbic Acid; Common Cold; Complementary Therapies; Food; Humans; Zinc

Topics: Antioxidants; Ascorbic Acid; Common Cold; Disease Susceptibility; Humans; Male

Topics: Antioxidants; Ascorbic Acid; Common Cold; Disease Susceptibility; Humans

A large number of placebo-controlled studies have shown that vitamin C supplementation alleviates the symptoms of the common cold, but widespread skepticism that vitamin C could have any significant effect remains. One of the most influential common cold studies, published in 1975, was carried out by Thomas Karlowski et al, at the National Institutes of Health. Their placebo consisted of lactose, which can easily be distinguished from ascorbic acid by taste. Karlowski et al, found a 17% decrease in the duration of cold episodes in the group administered vitamin C (6 g/day); however, they suggested that the decrease was entirely due to the placebo effect. In this article it will be shown that the placebo effect is not a valid explanation for the results of the Karlowski study, as it is inconsistent with their results. This is an important conclusion for two reasons. First, the placebo explanation becomes even more unreasonable as regards the reported benefits found in several other studies with valid placebo tablets. Second, as the results from the Karlowski study are not due to the placebo effect, their results can be used to assess the quantitative effects of vitamin C supplementation. The most important conclusions from Karlowski's study are that therapeutic vitamin C supplementation during a common cold episode appears to be as effective as regular supplementation, and that there appears to be linear dose dependency at least up to 6 g/day. These findings suggest that large therapeutic vitamin C doses might alleviate the symptoms of the common cold substantially.

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Dose-Response Relationship, Drug; Humans; Placebo Effect; Reproducibility of Results; Research Design

Several studies have observed an increased risk of respiratory infections in subjects doing heavy physical exercise. Vitamin C has been shown to affect some parts of the immune system, and accordingly it seems biologically conceivable that it could have effects on the increased incidence of respiratory infections caused by heavy physical stress. In this report the results of three placebo-controlled studies that have examined the effect of vitamin C supplementation on common cold incidence in subjects under acute physical stress are analyzed. In one study the subjects were school-children at a skiing camp in the Swiss Alps, in another they were military troops training in Northern Canada, and in the third they were participants in a 90 km running race. In each of the three studies a considerable reduction in common cold incidence in the group supplemented with vitamin C(0.6-1.0 g/day) was found. The pooled rate ratio (RR) of common cold infections in the studies was 0.50 (95% CI: 0.35-0.69) in favour of vitamin C groups. Accordingly, the results of the three studies suggest that vitamin C supplementation may be beneficial for some of the subjects doing heavy exercise who have problems with frequent upper respiratory infections.

Topics: Ascorbic Acid; Child; Common Cold; Exercise; Humans; Incidence; Randomized Controlled Trials as Topic; Respiratory Tract Infections

To examine the hypothesis that the increase in fibrinogen concentration and respiratory infections in winter is related to seasonal variations in vitamin C status (assessed with serum ascorbate concentration).. Longitudinal study of individuals seen at intervals of two months over one year.. Cambridge.. 96 men and women aged 65-74 years living in their own homes.. Haemostatic factors fibrinogen and factor VIIC; acute phase proteins; respiratory symptoms; respiratory function.. Mean dietary intake of vitamin C varied from about 65 mg/24 h in winter to 90 mg/24 h in summer; mean serum ascorbate concentration ranged from 50 mumol/l in winter to 60 mumol/l in summer. Serum ascorbate concentration was strongly inversely related to haemostatic factors fibrinogen and factor VIIC as well as to acute phase proteins but not to self reported respiratory symptoms or neutrophil count. Serum ascorbate concentration was also related positively to forced expiratory volume in one second. An increase in dietary vitamin C of 60 mg daily (about one orange) was associated with a decrease in fibrinogen concentrations of 0.15 g/l, equivalent (according to prospective studies) to a decline of approximately 10% in risk of ischaemic heart disease.. High intake of vitamin C has been suggested as being protective both for respiratory infection and for cardiovascular disease. These findings support the hypothesis that vitamin C may protect against cardiovascular disease through an effect on haemostatic factors at least partly through the response to infection; this may have implications both for our understanding of the pathogenetic mechanisms in respiratory and cardiovascular disease and for the prevention of such conditions.

Topics: Aged; Antioxidants; Ascorbic Acid; C-Reactive Protein; Cardiovascular Diseases; Common Cold; Factor VII; Female; Fibrinogen; Hemostasis; Humans; Longitudinal Studies; Male; Risk Factors; Seasons

In 1975 Thomas Chalmers analyzed the possible effect of vitamin C on the common cold by calculating the average difference in the duration of cold episodes in vitamin C and control groups in seven placebo-controlled studies. He found that episodes were 0.11 +/- 0.24 (SE) days shorter in the vitamin C groups and concluded that there was no valid evidence to indicate that vitamin C is beneficial in the treatment of the common cold. Chalmers' review has been extensively cited in scientific articles and monographs. However, other reviewers have concluded that vitamin C significantly alleviates the symptoms of the common cold. A careful analysis of Chalmers' review reveals serious shortcomings. For example, Chalmers did not consider the amount of vitamin C used in the studies and included in his meta-analysis was a study in which only 0.025-0.05 g/day of vitamin C was administered to the test subjects. For some studies Chalmers used values that are inconsistent with the original published results. Using data from the same studies, we calculated that vitamin C (1-6 g/day) decreased the duration of the cold episodes by 0.93 +/- 0.22 (SE) days; the relative decrease in the episode duration was 21%. The current notion that vitamin C has no effect on the common cold seems to be based in large part on a faulty review written two decades ago.

Topics: Ascorbic Acid; Common Cold; Controlled Clinical Trials as Topic; Humans; Meta-Analysis as Topic; Placebos

This hypothesis suggests that psychosocial stress is the pivotal determinator of many modern day disorders in consequence to consuming today's nutritional intakes of ascorbic acid and sodium. For it seems, as a result of our tropical African evolution, present day intakes of these essential nutrients are incompatible with the maintenance of bodily homeostasis when the body is subjected to any form of stress. In addition, the climatic conditions under which most of us live are seemingly ill-suited to experiencing stress, since it appears that a constituent part of the bodily stress response remains exclusively designed to be effective in a hot tropical environment, where the stress can be expected to be accompanied by thermoregulation sweating and an overheated body. For without such an occurrence coinciding with stress, the stress response itself appears to have been transposed into a reaction that inhibits the body's ability to resist infection and disease.

Topics: Ascorbic Acid; Biological Evolution; Common Cold; Humans; Life Style; Neoplasms; Sodium, Dietary; Stress, Psychological

Reviewing the literature is a scientific inquiry that needs a clear design to preclude bias. It is a real enterprise if one aims at completeness of the literature on a certain subject. Going through refereed English language journals is not enough. On line databases are helpful, but mainly as a starting point. This article gives examples of systematic reviews on vitamin C and the common cold, pyridoxine against the premenstrual syndrome, homeopathy, and physiotherapy.

Topics: Ascorbic Acid; Clinical Trials as Topic; Common Cold; Complementary Therapies; Databases, Bibliographic; Humans; Information Storage and Retrieval; MEDLINE; Physical Therapy Modalities; Review Literature as Topic

To assess the comprehensiveness of Medline and Embase computer searches for controlled trials.. Comparison of articles found after an exhaustive search of the literature with the yield of a Medline or Embase search. This was performed for controlled clinical trials on the efficacy of three interventions: homoeopathy, ascorbic acid for common cold, and ginkgo biloba for intermittent claudication and cerebral insufficiency. The number of controlled trials found by exhaustive search of the literature was 107, 61 and 45, respectively.. For homoeopathy, ascorbic acid and ginkgo the proportion of all trials found by Medline was 17%, 36% and 31% respectively and for Embase 13%, 25% and 58% respectively. After checking of the references in the Medline articles 44%, 79% and 76% of all trials were identified. After checking of the references in the Embase articles 42%, 72% and 93% of all trials were identified. About 20% of the articles was not correctly indexed. Of the best trials 68%, 91% and 83% could be found with Medline and 55%, 82% and 92% of the best trials were identified through Embase.. For the topics mentioned, Medline and Embase searches are sufficient to get an impression of the evidence from controlled trials, but only if references in the articles are followed for further evidence. If one wants to get a more complete picture, additional search strategies make sense. Of course, this picture may be different for other topics.

Topics: Abstracting and Indexing; Ascorbic Acid; Brain Ischemia; Clinical Trials as Topic; Common Cold; Homeopathy; Humans; Information Systems; Intermittent Claudication; MEDLINE; Plants, Medicinal

Topics: Adult; Air Pollution; Ascorbic Acid; Carboxyhemoglobin; Common Cold; Female; Forced Expiratory Flow Rates; Humans; Male; Middle Aged; Reference Values; Smoking

Topics: Ascorbic Acid; Common Cold; Humans; Neutrophils

Topics: Administration, Intranasal; Ascorbic Acid; Common Cold; Humans; Powders

Joshandah, polypharmaceutical herbal preparations, are used in the form of a sweetened decoction for the treatment of common cold, catarrh, cough and associated fevers in Unani (Greco-Arab) medicine. The rationale of their therapeutic efficacy is discussed in the light of reported chemico-pharmacological properties of the ingredients.

Topics: Ascorbic Acid; Common Cold; Cough; Fever; Humans; Phytotherapy; Plants, Medicinal

Topics: Animals; Ascorbic Acid; Common Cold; Female; Humans; Iron; Male

Topics: Aged; Ascorbic Acid; Common Cold; Female; Humans; Kinetics; Leukocytes; Male; Nutritional Requirements; Sex Factors; Species Specificity; Tissue Distribution

Topics: Ascorbic Acid; Common Cold; Diseases in Twins; Female; Genetic Variation; Genotype; Humans; Phenotype; Placebos; Pregnancy; Twins; Twins, Monozygotic

Topics: Animals; Ascorbic Acid; Cats; Common Cold; Diet Fads; Humans; Mental Disorders; Neoplasms; Niacin; Orthomolecular Therapy; Receptors, Cholinergic; Thiamine

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Ascorbic Acid; Common Cold; Double-Blind Method; Humans; Placebos; Research Design

Topics: Ascorbic Acid; Common Cold; Humans; Immunity, Innate; Orthomolecular Therapy

Topics: Ascorbic Acid; Biological Availability; Common Cold; Dose-Response Relationship, Drug; Humans

Topics: 2,3-Diketogulonic Acid; Adolescent; Adult; Ascorbic Acid; Common Cold; Female; Humans; Male; Middle Aged; Oxalates; Rhinovirus

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Ascorbic Acid; Common Cold; Cystitis; Humans; Substance-Related Disorders

The paper presents further investigations for a critical survey on the influences of drugs on laboratory methods. In controversion to the meanings you can find in the literature that ascorbic acid is most one of the important drugs to interfere with laboratory results we couldn't see in our systematical experimental investigation such results. Only in very extremly cases it seems to be right. Selected parameters of clinical chemistry (glucose, lactic dehydrogenase, aspartal-aminotransferase, alanine aminotransferase, alkaline phosphatase, protein, albumine, creatinine, butanol extractable iodine, ferrum) show under therapeutic conditions no influences of ascorbic acid, which can lead to diagnostic or therapeutic false interpretations. Above all the often mentioned example that glucose estimations in blood (reduction methods) can disturb if ascorbic acid is present, is abstracted in an uncritical manner how our experimental results may show.

Topics: Ascorbic Acid; Automation; Blood Glucose; Blood Proteins; Clinical Laboratory Techniques; Common Cold; Enzymes; Humans; Iodine; Iron

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Adolescent; Ascorbic Acid; Child; Common Cold; Humans; Infant

This study examined the effectiveness of several behavioral techniques on compliance of college students taking vitamin C on q.i.d. regimen. Compliance was assessed by a new technique using a variation of the urine tracer procedure designed specifically for this study. Subjects were provided vitamin C tablets, with three tablets per week containing phenazopyridine, a drug that produces a bright red-orange urine discoloration. Subjects were requested to indicate when urine discolorations occurred, and compliance was assessed by comparing the time of their report to the time predicted on the basis of the scheduled sequence of vitamin C and phenazopyridine tablets. Baseline compliance was assessed for 72 subjects over a three-week period, with the 40 most noncompliant subjects randomly assigned to four groups for Treatment I. The groups were: self-monitoring, taste, taste and self-monitoring, and a no-treatment control group. The self-monitoring procedure involved recording the time medicine was taken; the taste procedure involved providing the subjects with flavored tablets to increase the saliency of tablet taking; and the self-monitoring and taste procedure involved providing subjects with flavored tablets and asking them to record the flavor of each tablet they ingested. At the end of six weeks, half the subjects in each of these groups participated in response-cost procedures while the remaining subjects continued with their previous procedures. Response-cost procedures were implemented by returning a portion of the subjects' deposit only if a preset compliance criterion was met. Treatment II procedures were implemented for an additional three weeks. Results indicated the self-monitoring and taste plus self-monitoring procedures were superior during Treatment I. The implementation of response cost during Treatment II was associated with a marked improvement in compliance, independent of the history of noncompliance. The effects of the taste plus self-monitoring procedure were maintained during Treatment II and results obtained by this procedure were not significantly different from effects of response cost.

Topics: Ascorbic Acid; Behavior Therapy; Common Cold; Flavoring Agents; Humans; Patient Compliance; Phenazopyridine; Reinforcement, Psychology; Self-Assessment

Topics: Ascorbic Acid; Common Cold; Humans; Orthomolecular Therapy

Topics: Adolescent; Adult; Arteriosclerosis; Ascorbic Acid; Cholesterol; Common Cold; Double-Blind Method; Humans; Middle Aged; Neoplasms; Placebos

A sizable segment of the population was found to be taking large quantities of vitamin C to reduce the number or severity of upper respiratory infections. To determine the affect of this supplementation on iron balance, multiple radioiron absorption tests were performed in 63 male subjects. The increase in iron absorption from a semisynthetic meal was directly proportional to the amount of ascorbic acid added over a range of 25 to 1,000 mg. The ratio of iron absorption with/without ascorbic acid at these two extremes was 1.65 and 9.57, respectively. The relative increase was substantially less when the test meal contained meat. A large dose of vitamin C taken with breakfast did not effect iron absorption from the noon or evening meal. A telephone survey of 100 individuals revealed that 67 were taking supplemental ascorbic acid in doses ranging as high as 2 g daily. The average intake of supplemental ascrobic acid in this population was 280 mg daily. If taken only with breakfast, this level of supplementation would produce a nearly 2-fold increase in the amount of iron absorbed daily. If taken in divided doses with each mean, the increase in iron absorption would be more than 3-fold.

Topics: Adolescent; Adult; Ascorbic Acid; Common Cold; Diet; Ferritins; Humans; Intestinal Absorption; Iron; Male; Stimulation, Chemical

Topics: Ascorbic Acid; Common Cold; Humans; Patient Compliance

There is a certain presumptive evidence for believing than AA has functions other than the simple prevention of classical scurvy; whether these extra-antiscorbutic functions are attributable to AA itself, or to one or more of its metabolites, is not known. Tissue saturation with AA would appear to provide a good insurance against defects in these extra-antiscorbutic areas. ttissue saturation is attainable by a daily intake of 100-150 mg in man; there are no compelling reasons for using megadoses of AA and the emphasis should be on the avoidance of chronic hypovitaminosis C. There is suggestive evidence that megadoses of AA could be physiologically disadvantageous--particularly with regard to in-utero exposure and in persons exposed to high environmental levels of toxic metals.

Topics: Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Cholesterol; Common Cold; Humans; Longevity; Metals; Scurvy

Topics: Adolescent; Ascorbic Acid; Child; Common Cold; Humans

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Animals; Ascorbic Acid; Common Cold; Drug Evaluation; Humans

Topics: Ascorbic Acid; Child; Common Cold; Humans; Male

Topics: Animals; Ascorbic Acid; Common Cold; Diet; Humans

Ascorbic acid concentrations have been measured in leukocytes and plasma following oral administration of 2000 mg vitamin C in the same subjects while they had cold symptoms and after recovery from their colds. Plasma and leukocyte concentrations rose significantly in females, but only plasma concentrations rose in males, after the loading dose during colds. In the postcold tests, only plasma concentrations rose in both sexes. There was a significant difference in plasma leukocyte regression coefficients between the cold and postcold tests in females. Ascorbic acid passes into the plasma for metabolic purposes, and its storage is less in the leukocytes, during colds. Males had worse colds than females because their catarrhal symptoms were more severe. Higher tissue concentrations of ascorbic acid tended to be associated with low total, toxic, and catarrhal symptom values. A rise in tissue ascorbic acid was associated with less severe catarrhal symptoms in females. Ascorbic acid concentrations in the plasma and tongue were significantly higher after the subjects had recovered from their cold symptoms. Increasing the loading dose of vitamin C from 500 to 2000 mg more than doubled the leukocyte concentration of ascorbic acid in females. The higher dose enabled uptake of the vitamin into the leukocytes to take place over a 4-hour period. It did not give rise to increased uptake into male leukocytes. Administration of supplementary vitamin C elevated plasma ascorbic acid. The ascorbic acid then passed into the tissues depleted of vitamin C during the cold syndrome. A single supplementary dose of 2000 mg vitamin C can replete leukocyte ascorbic acid during a 4-hour period in females, but a larger dose may be necessary in males.

Topics: Ascorbic Acid; Common Cold; Female; Humans; Leukocytes; Male; Saliva; Sex Factors; Time Factors

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Antigens; Ascorbic Acid; Common Cold; Dust; Humans; Hypersensitivity; Leukocytes; Mites; Nasal Cavity; Respiratory Hypersensitivity; Seasons

Topics: Anti-Bacterial Agents; Ascorbic Acid; Common Cold; Diet; Penicillins; Respiratory Tract Infections; Tetracycline

Topics: Ascorbic Acid; Common Cold; Female; Humans; Leukocytes; Pregnancy; Substance Withdrawal Syndrome

Topics: Ascorbic Acid; Aspirin; Common Cold; Female; Humans; Leukocytes; Male

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Ascorbic Acid; Common Cold; Humans; Male

Topics: Administration, Oral; Adult; Ascorbic Acid; Common Cold; Histamine H1 Antagonists; Humans; Respiratory System

Topics: Ascorbic Acid; Ascorbic Acid Deficiency; Aspirin; Barbiturates; Common Cold; Humans; Hypercholesterolemia; Phenylbutazone; Pressure Ulcer; Tetracycline

Topics: Ascorbic Acid; Common Cold; Humans; Infant; Infant, Newborn

Topics: Ascorbic Acid; Common Cold; Female; Humans; Leukocyte Count; Leukocytes; Male; Sex Factors; Time Factors

Topics: Adrenal Glands; Ascorbic Acid; Biological Transport; Chemical Phenomena; Chemistry; Common Cold; Epinephrine; Evaluation Studies as Topic; Humans; Leukocytes; Models, Biological; Models, Molecular; Organ Specificity; Oxidation-Reduction; Solubility

Topics: Age Factors; Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Common Cold; Female; Guinea Pigs; Humans; Leukocytes; Male; Sex Factors

Topics: Ascorbic Acid; Common Cold; Food; Humans; Hydrogen-Ion Concentration; Methods; Vitamin B 12

Topics: Academies and Institutes; Adult; Ascorbic Acid; Child; Child, Preschool; Common Cold; Evaluation Studies as Topic; Female; Fetus; Humans; Hydrogen-Ion Concentration; Infant; Infant, Newborn; Pediatrics; Pregnancy; Urinary Calculi; Urinary Tract Infections; Urine

Topics: Adrenal Glands; Age Factors; Animals; Ascorbic Acid; Body Weight; Circadian Rhythm; Common Cold; Diet; Female; Gonadal Steroid Hormones; Guinea Pigs; Hematopoiesis; Humans; Hydrogen-Ion Concentration; Iron; Leukocytes; Liver; Male; Saliva; Scurvy; Sex Factors; Time Factors

Topics: Adult; Ascorbic Acid; Blood Platelets; Common Cold; Contraceptives, Oral; Estrogens; Female; Humans; Leukocytes; Male; Middle Aged; Pregnancy; Progesterone; Sex Factors

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Ascorbic Acid; Cervix Mucus; Common Cold; Female; Humans; Infertility, Female; Pregnancy; Scurvy; Self Medication

Topics: Adult; Ascorbic Acid; Common Cold; Female; Fertility; Humans; Infertility, Female; Pregnancy

Topics: Ascorbic Acid; Child; Common Cold; Female; Fertility; Humans; Male; Pregnancy; Sex Factors

Topics: Adenocarcinoma, Bronchiolo-Alveolar; Aging; Angioedema; Ascorbic Acid; Common Cold; Food; Headache; History, 20th Century; Hormones; Humans; Respiratory Insufficiency; Therapeutics

Topics: Ascorbic Acid; Colorimetry; Common Cold; Histamine H1 Antagonists; Humans; Methods; Phenylephrine; Spectrophotometry, Ultraviolet

Topics: Ascorbic Acid; Common Cold; Humans; Schizophrenia; Vitamins

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Ascorbic Acid; Common Cold; Food, Fortified; Humans; Scurvy; Tetracycline

Topics: Ascorbic Acid; Common Cold; Diarrhea; Female; Humans; Leukocytes; Male; Time Factors

Topics: Ascorbic Acid; Child; Common Cold; Humans; Leukocytes

Topics: Ascorbic Acid; Common Cold; Female; Humans; Male; Sex Factors

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Ascorbic Acid; Bacterial Infections; Common Cold; Gingivitis; Humans; Scurvy

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Adolescent; Adult; Ascorbic Acid; Cholesterol; Common Cold; Fasting; Humans; Placebos

Topics: Alcohols; Ascorbic Acid; Aspirin; Atropa belladonna; Common Cold; Dosage Forms; Flavonoids; Histamine H1 Antagonists; Nasal Decongestants; Nonprescription Drugs; Pharmaceutical Preparations; Phytotherapy; Plants, Medicinal; Plants, Toxic; Self Medication; Sympathomimetics

Topics: Aged; Aging; Arteriosclerosis; Ascorbic Acid; Ascorbic Acid Deficiency; Back Pain; Common Cold; Humans; Mental Disorders; Nutritional Requirements; Pituitary-Adrenal System; Renal Dialysis; Shock, Traumatic; Stress, Physiological; Structure-Activity Relationship; Surgical Procedures, Operative

Topics: Arteriosclerosis; Ascorbic Acid; Common Cold; Humans; Methemoglobinemia

Topics: Aged; Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Child; Common Cold; Diet; Food; Food Handling; Humans; Nutritional Physiological Phenomena; Nutritional Requirements; Rats; Scurvy

Topics: Administration, Oral; Ascorbic Acid; Common Cold; Drug Evaluation; Humans

Topics: Ascorbic Acid; Biological Evolution; Common Cold; Food Analysis; Humans; Nutritional Requirements

Topics: Ascorbic Acid; Common Cold; Humans; Time Factors

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Ascorbic Acid; Common Cold; Humans; Nicotinic Acids

Topics: Ascorbic Acid; Common Cold; Nursing

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Adult; Ascorbic Acid; Ascorbic Acid Deficiency; Common Cold; Humans

Topics: Ascorbic Acid; Child; Common Cold; Humans

Topics: Ascorbic Acid; Common Cold; Humans; Respiratory Tract Infections; Virus Diseases

Topics: Ascorbic Acid; Common Cold; Humans

Topics: Anti-Bacterial Agents; Ascorbic Acid; Common Cold; Female; Humans; Male

Topics: Adenoviridae; Adenoviridae Infections; Antiviral Agents; Ascorbic Acid; Common Cold; Cough; Culture Techniques; Humans; Infections; Orthomyxoviridae; Orthomyxoviridae Infections; Picornaviridae; Respiratory Tract Infections; Virus Diseases

Topics: Anti-Bacterial Agents; Ascorbic Acid; Biomedical Research; Common Cold; Drug Therapy; Humans; Placebos; Protein Synthesis Inhibitors; Spiramycin; Tetracycline

Topics: Anti-Bacterial Agents; Ascorbic Acid; Bacterial Infections; Biomedical Research; Common Cold; Communicable Disease Control; Drug Therapy; Humans; Placebos; Protein Synthesis Inhibitors; Respiratory Tract Infections; Spiramycin; Tetracycline

Topics: Ascorbic Acid; Cardiovascular Agents; Child; Common Cold; Drug Therapy; Flavonoids; Humans

Topics: Anticoagulants; Ascorbic Acid; Breast Feeding; Calcium; Calcium, Dietary; Common Cold; Dental Caries; Female; Fluorides; Humans; Infections; Iodine; Lactation; Myocardial Infarction; Penicillins; Pregnancy; Preventive Medicine; Silver Nitrate; Sulfonamides; Urinary Calculi

Topics: Aminopyrine; Anti-Allergic Agents; Ascorbic Acid; Blindness; Common Cold; Double-Blind Method; Histamine H1 Antagonists; Humans; Rutin; Vasodilator Agents; Visually Impaired Persons

Topics: Ascorbic Acid; Caffeine; Common Cold; Diphenhydramine; Humans; Immune Tolerance; Nasal Decongestants; Pheniramine; Phenylephrine; Rhinitis; Rhinitis, Allergic, Seasonal; Vasoconstrictor Agents

Topics: Ascorbic Acid; Common Cold; Humans; Hypothermia, Induced; Vitamins

Topics: 8-Bromo Cyclic Adenosine Monophosphate; Ascorbic Acid; Biomedical Research; Common Cold; Humans; Vitamins

Topics: Ascorbic Acid; Common Cold; Flavonoids; Stress Disorders, Traumatic; Stress, Physiological; Vitamins

Topics: Ascorbic Acid; Common Cold; Flavonoids; Humans; Vitamins

Topics: Analgesics; Analgesics, Non-Narcotic; Anti-Allergic Agents; Antipyretics; Ascorbic Acid; Common Cold; Histamine H1 Antagonists; Humans; Influenza, Human

Topics: Analgesics; Analgesics, Non-Narcotic; Anti-Allergic Agents; Antipyretics; Ascorbic Acid; Common Cold; Histamine H1 Antagonists; Humans; Respiratory System; Respiratory Tract Infections

Topics: Ascorbic Acid; Biomedical Research; Common Cold; Humans; Vitamins

Topics: Ascorbic Acid; Biomedical Research; Common Cold; Humans

Topics: Ascorbic Acid; Biomedical Research; Common Cold; Humans; Occupational Health; Vitamins

Topics: Ascorbic Acid; Common Cold; Humans; Hypothermia, Induced; Vitamins

Topics: Ascorbic Acid; Common Cold; Histamine; Humans; Vitamins