ascorbic-acid and Kidney-Calculi

The relationship of ascorbic acid (AA) supplements and risk of kidney stones among men and women is controversial. This systematic evaluation was performed to obtain comprehensive evidence about the relationship of AA supplements and risk of kidney stones among men and women.. A systematic search of Pubmed, the Cochrane Library, Web of Science, Embase was performed to identify studies that exhibited the relationship of AA supplements and risk of kidney stones among men and women were published up to Mar 2017. Outcomes of interest included kidney stones incidence and risk factors.. Four studies estimating the association between AA supplements and risk of kidney stones were included for meta-analysis. The kidney stones incidence was significantly higher in men than women with AA supplements (OR= 1.62; 95% CI: 1.09 to 2.42; P=0.02). AA supplements (250-499mg/d, 1000-1499mg/d) was remarkably correlated with the risk of renal stones among men (OR= 1.14, 95% CI: 1.00 to 1.28, P=0.04; OR= 1.12, 95% CI: 1.11 to 1.13, P<0.00001; respectively). However, AA supplements (500-999 mg/d, >1500 mg/d) did not correlate with the risk of renal stones among men (OR= 1.20, 95% CI: 0.99 to 1.46, P=0.06; OR= 1.28, 95% CI: 1.00 to 1.63, P= 0.05; respectively). In addition, AA supplements (250-499mg/d, 500-999mg/d, 1000-1499mg/d, >1500mg/d) did not remarkably correlate with the risk of renal stones among women (OR= 1.00, 95% CI: 0.82 to 1.22, P=0.98; OR= 1.08, 95% CI: 0.99 to 1.18, P=0.09; OR= 0.99, 95% CI: 0.90 to 1.08, P=0.77; OR= 0.99, 95% CI: 0.99 to 1.09, P=0.88; respectively).. AA supplements was remarkably correlated with higher risk for kidney stones incidence in men, but not in women. Further multicenter, prospective and long-term follow-up RCTs are required to verify these findings.

Topics: Ascorbic Acid; Dietary Supplements; Female; Humans; Incidence; Kidney Calculi; Male; Risk Assessment; Sex Distribution; Vitamins

Urolithiasis is a condition that can cause significant morbidity among patients. Dietary manipulations traditionally advised include fluid, protein, oxalate, calcium, citrate, and sodium changes in the diet. Evidence-based practice guidelines suggest that there is not ample evidence to confidently recommend dietary changes, since inadequate studies have been done to quantify the risks of diet in stone formation. While fluid intake patterns have the weightiest evidence in the literature, not even fluid intake meets the guidelines for evidence-based practice. Health care providers should recognize that current patient education is largely based on intuition. It behooves us as clinicians to look critically at all our practices, review the available literature, and question what we believe we know. A summary of available literature is provided to guide the clinician in educating patients in reducing their risk of recurrent calcium oxalate stone disease.

Topics: Ascorbic Acid; Calcium Oxalate; Calcium, Dietary; Citrates; Dehydration; Diet, Protein-Restricted; Diet, Sodium-Restricted; Evidence-Based Medicine; Feeding Behavior; Fluid Therapy; Humans; Information Services; Internet; Kidney Calculi; Nurse's Role; Nutritional Sciences; Obesity; Oxalates; Patient Education as Topic; Phytotherapy; Practice Guidelines as Topic; Recurrence; Risk Factors

Vitamin C in its pure form or as a component of multivitamin and combined drugs belongs to the over-the-counter drugs that are available not only at the chemist's but in retail shops as well. Intensive promotion of the advantages of vitamin C as the compound that augments immunity to all sorts of infections, accelerates recovery, eliminates the symptoms of common cold and flu-like diseases, and contributes to general well-being, is of great importance to its intake in quantities far exceeding the recommended dietary allowance. Moreover, the subjects who simultaneously take several anti-common cold drugs are not aware of the fact that almost each of them contains ascorbic acid. Among numerous reports concerning positive effect of vitamin C as antioxidant and free radicals scavenger, there are also those pointing at its potentially pernicious effect. Vitamin C, especially in the doses exceeding daily recommended dietary allowance may result in oxalate crystallization, formation of advanced glycation end products and even exert prooxidant effect.

Topics: Animals; Ascorbic Acid; Gastrointestinal Diseases; Humans; Intestinal Absorption; Kidney Calculi

Cystinuria, an autosomal-recessive disorder, is the cause of 1 - 2 % of all kidney stones observed in adults and about 10 % of those observed in infants. Despite increasing understanding of underlying pathomechanisms, patients still form recurrent stones and have to undergo repeated interventions with increasing risk of renal insufficiency. Dietary and medical metaphylaxis may lower the frequency of recurrent stones but are often not practiced. Regular follow-up examinations and optimal therapy significantly enlarge stone-free intervals. This review offers an overview of the underlying pathogenetic mechanisms as well as guidance for diagnosis, monitoring, metaphylaxis and therapy of cystinuria following the recommendations of the Deutsche Gesellschaft für Urologie (DGU) and the European Association of Urology (EAU).

Topics: Adult; Age Factors; Angiotensin-Converting Enzyme Inhibitors; Ascorbic Acid; Captopril; Chelating Agents; Child; Cystinuria; Follow-Up Studies; Humans; Kidney Calculi; Lithotripsy; Penicillamine; Time Factors; Tiopronin; Ureteroscopy

The popularity of vitamin C can be attributed to Linus Pauling who, in the 1970s, recommended the use of vitamin C for the prevention of influenza. Vitamin C has subsequently been used extensively in a wide range of diseases. Ascorbic acid (vitamin C) has been incriminated as a possible risk factor for calcium oxalate stones due to its enzymatic conversion into oxalate. However, this lithogenic role has never been clearly established. Studies evaluating the effect of ascorbic acid on lithogenesis have reported contradictory results. Ascorbic acid has also been extensively used as an urine acidifier for the treatment of chronic or recurrent urinary tract infection. Once again, the data of the literature are contradictory. The purpose of this article was to review the effects of ascorbic acid on lithogenesis and urinary pH based on a review of the literature.

Topics: Ascorbic Acid; Humans; Kidney Calculi; Oxalates

The high incidence of recurrence after an initial stone event underscores the need for an effective medical prophylactic program. Dietary modification and drug therapies have long been advocated to reduce the likelihood of stone recurrence. While the efficacy of a high fluid intake has been validated in a randomized trial, the benefit of other dietary measures is based on modulation of urinary stone risk factors and outcomes derived from observational studies. Several drug therapies have been evaluated in a limited number of prospective, randomized trials and efficacy has been demonstrated for thiazides, allopurinol and alkali citrate in some populations of recurrent stone formers. The role of selective versus nonselective therapy for stone prevention awaits further study.

Topics: Allopurinol; Ascorbic Acid; Benzothiadiazines; Calcium, Dietary; Citric Acid; Diet; Dietary Proteins; Diuretics; Drinking; Humans; Kidney Calculi; Magnesium; Oxalic Acid; Phosphates; Recurrence; Risk Factors; Sodium Chloride Symporter Inhibitors; Sodium, Dietary

Topics: Adult; Allopurinol; Ascorbic Acid; Benzothiadiazines; Calcium; Calcium, Dietary; Dietary Proteins; Diuretics; Drinking; Humans; Kidney Calculi; Lithotripsy; Male; Oxalic Acid; Potassium Citrate; Potassium, Dietary; Recurrence; Sodium; Sodium Chloride Symporter Inhibitors; Sodium, Dietary

Dietary reference intakes (DRIs) for vitamin C for healthy U.S. populations are currently being formulated by the Panel on Dietary Antioxidants and Related Compounds of the Food and Nutrition Board of the Institute of Medicine. A major task of the Panel is to analyze the evidence of adverse effects of high-dose vitamin C intakes to derive, if appropriate, a Tolerable Upper Intake Level (UL) for vitamin C. The present report details current and past research examining potential adverse effects of supplemental vitamin C. The available data indicate that very high intakes of vitamin C (2-4 g/day) are well tolerated biologically in healthy mammalian systems. Currently, strong scientific evidence to define and defend a UL for vitamin C is not available.

Topics: Adult; Animals; Ascorbic Acid; Biomarkers; Female; Humans; Kidney Calculi; Nutrition Policy; Oxidative Stress

Even though a certain part of oxalate in the urine derives from metabolized ascorbic acid (AA), the intake of high doses of vitamin C does not increase the risk of calcium oxalate kidney stones due to physiological regulatory factor: gastrointestinal absorption as well as renal tubular reabsorption of AA are saturable processes, and the metabolic transformation of AA to oxalate is limited as well. Older assays for urinary oxalate favored in vitro conversion of AA to oxalate during storage and processing of the samples. Recurrent stone formers and patients with renal failure who have a defect in AA or oxalate metabolism should restrict daily vitamin C intakes to approximately 100 mg. But in the large-scale Harvard Prospective Health Professional Follow-Up Study, those groups in the highest quintile of vitamin C intake (> 1,500 mg/day) had a lower risk of kidney stones than the groups in the lowest quintiles.

Topics: Ascorbic Acid; Calcium Oxalate; Case-Control Studies; Dose-Response Relationship, Drug; Female; Follow-Up Studies; Humans; Intestinal Absorption; Kidney; Kidney Calculi; Male; Oxalates; Renal Insufficiency; Retrospective Studies; Risk Factors

Consensus from individual studies and several review articles is that consumption of supplemental vitamin C leads to no significant adverse health effects to humans in general. Individuals who have a history of kidney stone formation and those who experience iron overload should exercise caution before using supplemental vitamin C. Occasionally, individuals experience diarrhea or mild nausea. There is also the possibility that vitamin C taken simultaneously with other drugs may contribute to adverse health effects and that its interference in clinical laboratory tests will mask diagnosis of disease. Few controlled clinical trials exist that conclusively demonstrate the adverse health effects that humans may experience with supplemental vitamin C usage, and before definite conclusions can be made of the health hazards to humans, more clinical trials are required.

Topics: Ascorbic Acid; Drug Interactions; False Negative Reactions; Gastrointestinal Diseases; Humans; Intestinal Absorption; Iron; Kidney Calculi; Oxalates; Risk; Vitamin B 12

Topics: Adolescent; Ascorbic Acid; Biochemical Phenomena; Biochemistry; Child; Classification; Diet; Genetics, Medical; Glycine; Glycolates; Humans; Hyperoxaluria, Primary; Infant; Kidney Calculi; Metabolic Diseases; Metabolism; Nephrocalcinosis; Oxalates; Pathology; Terminology as Topic; Uremia; Urine; Vitamin B 6 Deficiency

Treatment with extracorporeal shock wave lithotripsy (ESWL), the preferred method of treating kidney stones <3 cm in size, has been shown to induce silent and often self-limiting acute and chronic lesions in the kidneys and adjacent organs. We conducted a randomized clinical trial to determine whether ESWL produces ischaemia and reperfusion injury in the kidneys and whether oral administration of antioxidants reduces the degree of short-term renal injury in patients treated with ESWL. The study included 120 patients with renal stones (1-3 cm in size) treated with ESWL. The patients were divided into three groups--patients in group A (n=39) served as a control group and were not given any antioxidants; patients in group B (n=41) were given two capsules of antioxidants "Nature Made R: " 2 h before ESWL, and 2 and 8 h after ESWL; and patients in group C (n=40) were given two capsules of the antioxidants 2 and 8 h after ESWL. Double 'J' stents were inserted in patients before treatment with ESWL. Blood and urine samples were obtained from all patients just before the start of treatment with ESWL, and at 2 and 24 h and on 7th and 28th day after ESWL. Serum levels of malondialdehyde (MDA), alpha-tocopherol, cholesterol, albumin and ascorbic acid, and alpha-tocopherol/cholesterol ratio were determined. Urinary levels of albumin and beta(2) microglobulin were also determined as measures of renal tubular injury. At 24 h after ESWL, patients given antioxidants (groups B + C) had significantly reduced mean serum concentration of MDA (P<0.001); higher levels of serum ascorbic acid (P<0.001) and serum albumin (P<0.001); lower alpha-tocopherol/cholesterol ratio, lower urinary albumin and beta(2 )microglobulin levels compared with patients who did not receive antioxidants (group A). These findings suggest that treatment with ESWL generates free radicals through ischaemic/reperfusion injury mechanism, and that oral administration of antioxidant may protect these patients from short term renal injury caused by ESWL.

Topics: Administration, Oral; Adult; alpha-Tocopherol; Antioxidants; Ascorbic Acid; beta 2-Microglobulin; Cholesterol; Dose-Response Relationship, Drug; Female; Free Radicals; Humans; Kidney; Kidney Calculi; Lithotripsy; Male; Malondialdehyde; Middle Aged; Reperfusion Injury; Serum Albumin

Currently, the recommended upper limit for ascorbic acid (AA) intake is 2000 mg/d. However, because AA is endogenously converted to oxalate and appears to increase the absorption of dietary oxalate, supplementation may increase the risk of kidney stones. The effect of AA supplementation on urinary oxalate was studied in a randomized, crossover, controlled design in which subjects consumed a controlled diet in a university metabolic unit. Stoneformers (n = 29; SF) and age- and gender-matched non-stoneformers (n = 19; NSF) consumed 1000 mg AA twice each day with each morning and evening meal for 6 d (treatment A), and no AA for 6 d (treatment N) in random order. After 5 d of adaptation to a low-oxalate diet, participants lived for 24 h in a metabolic unit, during which they were given 136 mg oxalate, including 18 mg 13C2 oxalic acid, 2 h before breakfast; they then consumed a controlled very low-oxalate diet for 24 h. Of the 48 participants, 19 (12 stoneformers, 7 non-stoneformers) were identified as responders, defined by an increase in 24-h total oxalate excretion > 10% after treatment A compared with N. Responders had a greater 24-h Tiselius Risk Index (TRI) with AA supplementation (1.10 +/- 0.66 treatment A vs. 0.76 +/- 0.42 treatment N) because of a 31% increase in the percentage of oxalate absorption (10.5 +/- 3.2% treatment A vs. 8.0 +/- 2.4% treatment N) and a 39% increase in endogenous oxalate synthesis with treatment A than during treatment N (544 +/- 131 A vs. 391 +/- 71 micromol/d N). The 1000 mg AA twice each day increased urinary oxalate and TRI for calcium oxalate kidney stones in 40% of participants, both stoneformers and non-stoneformers.

Topics: Adult; Ascorbic Acid; Body Mass Index; Body Weight; Calcium; Calcium Oxalate; Cross-Over Studies; Female; Humans; Hyperoxaluria; Kidney Calculi; Male; Oxalates; Reference Values; Risk Factors

To investigate the oxalate intake and the effect of an oxalate load on urinary oxalate excretion in calcium stone-forming (CSF) patients.. Prospective study.. University-affiliated outpatient Renal Lithiasis Unit.. Seventy (70) CSF and 41 healthy subjects (HS) collected a 24-hour urine sample and were submitted to a 3-day dietary record to determine mean oxalate (Ox), calcium (Ca) and vitamin C intake. Fifty-eight (58) CSF patients were randomly selected to receive milk (N = 28) or dark (N = 30) chocolate as an oxalate load.. Administration of either milk (94 mg Ox + 430 mg Ca) or dark chocolate (94 mg Ox + 26 mg Ca) for 3 days. A 24-hour urine sample was obtained before and after the load to determine calcium, oxalate, sodium, potassium, urea, and creatinine.. Oxalate intake and excretion.. CSF patients presented mean Ox intake of 98 +/- 137 mg/d, similar to that of HS (108 +/- 139 mg/d). Mean Ox and vitamin C intake was directly correlated with Ox excretion only in CSF. The consumption of dark chocolate induced a significant increase in mean urinary Ox (36 +/- 14 versus 30 +/- 10 mg/24 hr) not observed in the milk chocolate group. Thus, a 2-fold increase in Ox intake in this population of CSF patients produced a significant 20% increase in oxaluria, not observed when Ca was consumed simultaneously.. The present study suggests that even small increases in Ox intake affect oxalate excretion and the mitigation of urinary oxalate increase by Ca consumption reinforces that Ca and Ox intakes for CSF patients should be in balance. Further studies are necessary to assess whether or not a 20% increase in oxaluria will lead to a higher risk of stone formation.

Topics: Adult; Animals; Ascorbic Acid; Cacao; Calcium; Calcium, Dietary; Diet Records; Female; Humans; Hyperoxaluria; Kidney Calculi; Male; Milk; Oxalates

The contribution of ascorbate to urinary oxalate is controversial. The present study aimed to determine whether urinary oxalate and pH may be affected by vitamin C supplementation in calcium stone-forming patients.. Forty-seven adult calcium stone-forming patients received either 1 g (N=23) or 2 g (N=24) of vitamin C supplement for 3 days and 20 healthy subjects received 1 g. A 24-hour urine sample was obtained both before and after vitamin C for calcium, oxalate, magnesium, citrate, sodium, potassium, and creatinine determination. The Tiselius index was used as a calcium oxalate crystallization index. A spot fasting morning urine sample was also obtained to determine the urinary pH before and after vitamin C.. Fasting urinary pH did not change after 1 g (5.8 +/- 0.6 vs. 5.8 +/- 0.7) or 2 g vitamin C (5.8 +/- 0.8 vs. 5.8 +/- 0.7). A significant increase in mean urinary oxalate was observed in calcium stone-forming patients receiving either 1 g (50 +/- 16 vs. 31 +/- 12 mg/24 hours) or 2 g (48 +/- 21 vs. 34 +/- 12 mg/24 hours) of vitamin C and in healthy subjects (25 +/- 12 vs. 39 +/- 13 mg/24 hours). A significant increase in mean Tiselius index was observed in calcium stone-forming patients after 1 g (1.43 +/- 0.70 vs. 0.92 +/- 0.65) or 2 g vitamin C (1.61 +/- 1.05 vs. 0.99 +/- 0.55) and in healthy subjects (1.50 +/- 0.69 vs. 0.91 +/- 0.46). Ancillary analyses of spot urine obtained after vitamin C were performed in 15 control subjects in vessels with or without ethylenediaminetetraacetic acid (EDTA) with no difference in urinary oxalate between them (28 +/- 23 vs. 26 +/- 21 mg/L), suggesting that the in vitro conversion of ascorbate to oxalate did not occur.. These data suggest that vitamin C supplementation may increase urinary oxalate excretion and the risk of calcium oxalate crystallization in calcium stone-forming patients.

Topics: Adult; Antioxidants; Ascorbic Acid; Calcium; Calcium Oxalate; Crystallization; Female; Humans; Hydrogen-Ion Concentration; Kidney Calculi; Male; Middle Aged; Risk Factors

A total of 15 patients with unilateral nephrostomy tubes after extracorporeal shock wave lithotripsy received either 0 (placebo), 100, 500, 1,000 or 2,000 mg. ascorbic acid on days 2 and 3 postoperatively. Before and after administration, successive 6-hour urine specimens were collected from the nephrostomy tube and from the contralateral kidney directly into a preservative to stabilize ascorbic acid and oxalate. In 1 patient in each group preservative was omitted from the collection pouch. Urinary oxalate was then measured enzymatically after removal of ascorbic acid with sodium nitrite. Preservatives proved necessary for full recovery of analyte. At doses of 500 mg. or more of ascorbic acid there was a statistically significant increase in urinary oxalate equivalent to 1.2 to 1.8% of the millimoles of ascorbate administered. This represented an increase in urinary oxalate excretion of 6 to 13 mg. per day per 1,000 mg. ascorbic acid supplement. This amount would increase the risk of calcium oxalate urolithiasis.

Topics: Adult; Ascorbic Acid; Calcium Oxalate; Dose-Response Relationship, Drug; Drug Overdose; Female; Humans; Kidney Calculi; Male; Middle Aged; Risk Factors

17 cystine stone patients were treated with high doses of ascorbic acid (5 g p. d.). During the observation period, a total of only two natural passages of cystine stones could be observed. For five patients the therapeutic strategy was altered because the recurrence rate did not change and the cystine concentration in the urine was enhanced. One mixed calcium-oxalate/cystine stone had to be resected. In this case as well as on the occasion of further medical check-ups of other patients, an increased risk of calcium-oxalate stone formation was signalled by an enhanced oxalic-acid concentration in the 24-hour urine. Changes in blood serum and impairment in hepatic and renal functions were not observed. With three patients, the therapy had to be interrupted because of gastritis symptoms. The use of high-dose ascorbic acid therapy is recommended and is continued. In special cases, an additive of low do ses of alpha-mercaptopropionyl-glycine is recommended.

Topics: Adult; Aged; Ascorbic Acid; Child; Clinical Trials as Topic; Cystinuria; Disease Susceptibility; Dose-Response Relationship, Drug; Female; Humans; Hydrogen-Ion Concentration; Kidney Calculi; Long-Term Care; Male; Middle Aged; Oxalates; Oxalic Acid; Recurrence

The objective of this study is to evaluate the conventional dietary recommendations for stone prevention among patients in the National Health and Nutritional Examination Survey (NHANES) and compare dietary components and special diets between stone formers and non-stone formers. We analyzed the NHANES 2011-2018 dietary and kidney condition questionnaires, among 16,939 respondents who were included in this analysis. Dietary variables were selected based on the American Urological Association (AUA) guideline for Medical Management of Kidney Stones and from other studies on kidney stone prevention. Weighted multivariate logistic regression models were used to assess the relationship of dietary food components (categorized into quartiles) and dietary recommendations with kidney stone formation (yes vs no), adjusted for total caloric intake, comorbidities, age, race/ethnicity, and sex. The prevalence of kidney stones was 9.9%. Our results showed association of kidney stones with lower levels of potassium (p for trend = 0.047), which was strongest for < 2000 mg (OR = 1.35; 95% CI 1.01-1.79). Higher vitamin C intake was inversely associated with stone formation (p for trend = 0.012), particularly at daily intake levels between 60 and 110 mg (OR = 0.76; 95% CI 0.60-0.95) and above 110mcg (OR = 0.80; 95% CI 0.66-0.97). There were no associations between other dietary components and kidney stone formation. Higher levels of dietary vitamin C and potassium intake may be indicated for stone prevention and warrants further investigation.

Topics: Ascorbic Acid; Diet; Humans; Kidney Calculi; Nutrition Surveys; United States; Vitamins

Topics: Ascorbic Acid; Humans; Kidney Calculi; Scurvy

Hyperoxaluria and oxidative stress are risk factors in calcium oxalate (CaOx) stone formation. Supplement with antioxidant could be effective in prevention of recurrent stone formation. The present study aims to evaluate the protective effects of vitamin E and vitamin C in hyperoxaluric rat. The experiment was performed in rats for 21 days. Rats were divided into 5 groups as follows: control (group 1, n=8), hyperoxaluric rats (group 2, n=8), hyperoxaluric rats with vitamin E supplement (group 3, n=7), hyperoxaluric rats with vitamin C supplement (group 4, n=7) and hyperoxaluric rats with vitamin E and C supplement (group 5, n=7). Hyperoxaluria was induced by feeding hydroxyl L-proline (HLP) 2% w/v dissolved in drinking water. Intraperitoneal 200 mg/kg of vitamin E was given in groups 3 and 5 on days 1, 6, 11 and 16, while 500 mg of vitamin C was injected intravenously in groups 4 and 5 on days 1 and 11. Renal functions and oxidative status were measured. The urinary oxalate excretion was increased in HLP supplement rats, while glomerular filtration rate, proximal water and sodium reabsorption were significantly lower in group 2 compared with a control (P<0.05). Giving antioxidants significantly lower urinary calcium oxalate crystals (P<0.05). Hyperoxaluric rats had higher plasma malondialdehyde (PMDA) and lower urinary total antioxidant status (UTAS), which were alleviated by vitamin E and/or vitamin C supplement. In conclusion, giving combination of vitamin E and vitamin C exerts a protective role against HLP-induced oxalate nephropathy.

Topics: Animals; Antioxidants; Ascorbic Acid; Body Weight; Citrates; Drinking; Drug Therapy, Combination; Eating; Electrolytes; Hemodynamics; Hyperoxaluria; Kidney; Kidney Calculi; Kidney Glomerulus; Male; Oxalates; Protective Agents; Rats; Rats, Sprague-Dawley; Vitamin E

Topics: Ascorbic Acid; Calcium, Dietary; Child; Dietary Proteins; Evidence-Based Medicine; Humans; Kidney Calculi; Micronutrients; Nutrition Therapy; Plant Proteins; Recommended Dietary Allowances; Vitamin D

Topics: Ascorbic Acid; Calcium, Dietary; Child; Dietary Proteins; Evidence-Based Medicine; Humans; Kidney Calculi; Micronutrients; Nutrition Therapy; Plant Proteins; Recommended Dietary Allowances; Vitamin D

Previous studies of vitamin C and kidney stones were conducted mostly in men and either reported disparate results for supplemental and dietary vitamin C or did not examine dietary vitamin C.. Prospective cohort analysis.. 156,735 women in the Nurses' Health Study (NHS) I and II and 40,536 men in the Health Professionals Follow-up Study (HPFS).. Total, dietary, and supplemental vitamin C intake, adjusted for age, body mass index, thiazide use, and dietary factors.. Incident kidney stones.. During a median follow-up of 11.3 to 11.7 years, 6,245 incident kidney stones were identified. After multivariable adjustment, total vitamin C intake (<90 [reference], 90-249, 250-499, 500-999, and ≥1,000mg/d) was not significantly associated with risk for kidney stones among women, but was among men (HRs of 1.00 [reference], 1.19 [95% CI, 0.99-1.46], 1.15 [95% CI, 0.93-1.42], 1.29 [95% CI, 1.04-1.60], and 1.43 [95% CI, 1.15-1.79], respectively; P for trend = 0.005). Median total vitamin C intake for the 500- to 999-mg/d category was ∼700mg/d. Supplemental vitamin C intake (no use [reference], <500, 500-999, and ≥1,000mg/d) was not significantly associated with risk for kidney stones among women, but was among men (HR, 1.19 [95% CI, 1.01-1.40] for ≥1,000mg/d; P for trend = 0.001). Dietary vitamin C intake was not associated with stones among men or women, although few participants had dietary intakes > 700mg/d.. Nutrient intakes derived from food-frequency questionnaires, lack of data on stone composition for all cases.. Total and supplemental vitamin C intake was significantly associated with higher risk for incident kidney stones in men, but not in women.

Topics: Adult; Aged; Ascorbic Acid; Body Mass Index; Diet; Dietary Supplements; Female; Follow-Up Studies; Humans; Italy; Kidney Calculi; Male; Middle Aged; Prospective Studies; Risk Assessment; Risk Factors; Sex Factors; Surveys and Questionnaires; United States; Vitamins

Topics: Ascorbic Acid; Diet; Dietary Supplements; Humans; Kidney Calculi; Risk; Risk Factors

Renal epithelial cell injury by reactive oxygen species is a prerequisite step in the pathogenesis of urolithiasis, and there is increasing evidence that reactive oxygen species is produced and oxidative stress (OS) is developed during idiopathic calcium oxalate nephrolithiasis. It appears that the administration of natural antioxidants has been used to protect against nephrolithiasis in human and experimental animals.. Calcium oxalate urolithiasis was induced experimentally by administration of 0.75 % v/v ethylene glycol in drinking water of male Wistar rats weighing 150-200 g. Study was conducted in 4- and 8-week periods. In the 4-week period, Group 1 (control) was fed a standard commercial diet. Group 2 received the same diet with the addition of 0.75 % of ethylene glycol (EG). Group 3 received EG plus the diet, and water with additional antioxidant nutrients, and lemon juice as the dietary source of citrate (EG + AX). Group 4 was the same as Group 3, but with no EG in water. In the 8-week study protocol, Group 5 was fed the standard diet with EG in water for the first 28 days, followed with no EG. Group 6 (curative group) received the diet with EG for the first 28 days, followed by discontinuation of EG plus the addition of antioxidant nutrients. Group 7 was provided the diet with antioxidant nutrients for 8 weeks. Group 8 (preventive group) received the diet with antioxidant nutrients for 4 weeks, followed by antioxidant nutrients with EG for the next 4 weeks. Lime juice was given along the antioxidants. After treatment period, kidneys were removed and used for histopathological examination.. In the 4-week study, the mean number of crystal deposits in Group 2 was significantly higher than that of animals in Group 3. After 8 weeks, animals given curative antioxidant supplementation within the second 4-week period developed fewer deposits in Group 6 as compared to Group 5 animals. In the other preventive AX loading Group 8, the number of crystal deposits was substantially less than that of either Group 2 or Group 5 animals (EG-treated rats).. Results showed a beneficial effect on treating and superior renal protection for preventing stone deposition in the rat kidney. These results provide a scientific rationale for preventive and treatment roles of antioxidant nutrient complex in human kidney stone disease.

Topics: Animals; Antioxidants; Ascorbic Acid; Beverages; Calcium Oxalate; Citrus aurantiifolia; Dietary Supplements; Ethylene Glycol; Kidney Calculi; Male; Rats, Wistar; Selenium; Vitamin A; Vitamin B 6; Vitamin E; Zinc

Topics: Ascorbic Acid; Calcium Oxalate; Humans; Kidney Calculi; Male

Topics: Ascorbic Acid; Calcium Oxalate; Humans; Kidney Calculi; Male

Topics: Ascorbic Acid; Calcium Oxalate; Humans; Kidney Calculi; Male

Topics: Ascorbic Acid; Dietary Supplements; Female; Humans; Kidney Calculi; Male; Risk Factors; Vitamins

Topics: Aged; Ascorbic Acid; Dietary Supplements; Humans; Kidney Calculi; Male; Middle Aged; Population Surveillance; Risk Assessment; Sweden

Topics: Aged; Ascorbic Acid; Calcium Oxalate; Cohort Studies; Dietary Supplements; Dose-Response Relationship, Drug; Humans; Incidence; Kidney Calculi; Male; Middle Aged; Proportional Hazards Models; Prospective Studies; Risk Assessment; Sweden; Vitamins

Topics: Ascorbic Acid; Calcium Oxalate; Humans; Kidney Calculi; Male

Topics: Ascorbic Acid; Calcium Oxalate; Dietary Proteins; Drinking Behavior; Humans; Kidney Calculi; Sodium Chloride, Dietary

Topics: Ascorbic Acid; Bariatric Surgery; Calcium Oxalate; Diabetes Mellitus, Type 2; Humans; Kidney Calculi; Postoperative Complications; Risk Factors

Higher levels of urinary oxalate substantially increase the risk of calcium oxalate kidney stones. However, the determinants of urinary oxalate excretion are unclear. The objective was to examine the impact of dietary factors, age, body size, diabetes, and urinary factors on 24-h urinary oxalate.. We conducted a cross-sectional study of 3348 stone forming and non-stone-forming participants in the Health Professionals Follow-up Study (men), the Nurses' Health Study (older women), and the Nurses' Health Study II (younger women).. Median urinary oxalate was 39 mg/d in men, 27 mg/d in older women, and 26 mg/d in younger women. Participants in the highest quartile of dietary oxalate excreted 1.7 mg/d more urinary oxalate than participants in the lowest quartile (P trend 0.001). The relation between dietary and urinary oxalate was similar in individuals with and without nephrolithiasis. Participants consuming 1000 mg/d or more of vitamin C excreted 6.8 mg/d more urinary oxalate than participants consuming <90 mg/d (P trend < 0.001). Body mass index, total fructose intake, and 24-h urinary potassium, magnesium, and phosphorus levels also were positively associated with urinary oxalate. Calcium intake and age were inversely associated with urinary oxalate. After adjustment for body size, participants with diabetes excreted 2.0 mg/d more urinary oxalate than those without diabetes (P < 0.01).. The impact of dietary oxalate on urinary oxalate appears to be small. Further investigation of factors influencing urinary oxalate may lead to new approaches to prevent calcium kidney stones.

Topics: Adult; Age Factors; Aged; Ascorbic Acid; Body Mass Index; Body Weight; Circadian Rhythm; Cross-Sectional Studies; Diabetes Complications; Diet; Dietary Supplements; Female; Fructose; Humans; Kidney Calculi; Magnesium; Male; Middle Aged; Nutrition Assessment; Oxalates; Phosphorus; Potassium

Previous studies have shown that urogenital tuberculosis (GuTb) patients treated or untreated with regular anti-Tb regimen excrete comparatively high levels of urinary stone forming constituents than normal subjects. Enhanced oxidative stress is also considered as a prime factor that accelerates urolithiasis. The present study was aimed to determine antioxidant status and lipid peroxidation of these individuals in order to assess their risk for kidney stone formation.. GuTb patients and age-matched normal subjects were divided into four groups: I: normal subjects (n=60), II: GuTb patients a day before treatment (n=72), III: GuTb patients after treatment with isoniazid (300 mg), rifampicin (450 mg) and pyrazinamide (1.5 g) per day for 60 days (n=42), and IV: GuTb patients supplemented with vitamin E (200 mg/day) along with regular chemotherapy for 60 days (n=30). Blood was collected and tested for various markers of oxidative stress.. Increased levels of lipid peroxidation, protein carbonyls (PCO), advanced oxidative protein products (AOPP) and reduced antioxidant defenses by impairment in enzyme activities like superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione and decreased plasma concentrations of non enzymatic antioxidants like vitamins C and E were observed in the treated and untreated GuTb patients.. These biochemical disparities may lead to membrane disintegrity, which is favorable for retention of mirolithis. Advocation of vitamin E enhanced the antioxidant status of the plasma, thereby preventing membrane injury, consequently reducing the risk of stone formation in urogenital tuberculosis patients, who were treated with their routine anti-tuberculosis drug regimen.

Topics: Antioxidants; Ascorbic Acid; Catalase; Female; Glutathione; Glutathione Peroxidase; Humans; Kidney Calculi; Lipid Peroxidation; Male; Middle Aged; Oxidative Stress; Superoxide Dismutase; Treatment Outcome; Tuberculosis, Urogenital; Vitamin E

Increased rates of either oxalate absorption or endogenous oxalate synthesis can contribute to hyperoxaluria, a primary risk factor for the formation of calcium oxalate-containing kidney stones. This study involves a comparative assessment of oxalate absorption and endogenous oxalate synthesis in subpopulations of stone formers (SFs) and non-stone formers (NSFs) and an assessment of the effect of ascorbate supplementation on oxalate absorption and endogenous oxalate synthesis.. Twenty-nine individuals with a history of calcium oxalate kidney stones (19 men, 10 women) and 19 age-matched NSFs (8 men, 11 women) participated in two 6-day controlled feeding experimental periods: ascorbate-supplement (2 g/d) and no-supplement treatments. An oxalate load consisting of 118 mg of unlabeled oxalate and 18 mg of 13C2 -oxalic acid was administered the morning of day 6 of each experimental period.. Mean 13C2 -oxalic acid absorption averaged across the ascorbate and no-supplement treatments was significantly greater in SFs (9.9%) than NSFs (8.0%). SFs also had significantly greater 24-hour post-oxalate load urinary total oxalate and endogenous oxalate levels with both treatments. Twenty-four-hour urinary total oxalate level correlated strongly with both 13C2 -oxalic acid absorption (SFs, r = 0.76; P < 0.01; NSFs, r = 0.62; P < 0.01) and endogenous oxalate synthesis (SFs, r = 0.95; P < 0.01; NSFs, r = 0.92; P < 0.01).. SFs are characterized by greater rates of both oxalate absorption and endogenous oxalate synthesis, and both these factors contribute to the hyperoxaluric state. The finding that ascorbate supplementation increased urinary total and endogenous oxalate levels suggested that this practice is a risk factor for individuals predisposed to kidney stones.

Topics: Adult; Aged; Ascorbic Acid; Calcium Oxalate; Female; Humans; Hyperoxaluria; Kidney; Kidney Calculi; Male; Middle Aged; Oxalates

Diet plays an important role in the pathogenesis of kidney stones. Because the metabolism of many dietary factors, such as calcium, may change with age, the relation between diet and kidney stones may be different in older adults. Uncertainty also remains about the association between many dietary factors, such as vitamin C, magnesium, and animal protein, and the risk of kidney stone formation. To examine the association between dietary factors and the risk of incident, symptomatic kidney stones in men and to determine whether these associations vary with age, a prospective cohort study was conducted of 45,619 men without a history of nephrolithiasis. Self-administered food frequency questionnaires were used to assess diet every 4 yr. A total of 1473 incident symptomatic kidney stones were documented during 477,700 person-years of follow-up. For men aged <60 yr, the multivariate relative risk (RR) for stone formation in the highest quintile of dietary calcium as compared with the lowest quintile was 0.69 (95% confidence interval [CI], 0.56 to 0.87; P = 0.01 for trend). By contrast, there was no association between dietary calcium and stone formation in men aged 60 yr or older. The multivariate RR for men who consumed 1000 mg or greater of vitamin C per day compared with those who consumed less than the recommended dietary allowance of 90 mg/d was 1.41 (95% CI, 1.11 to 1.80; P = 0.01 for trend). Other dietary factors showed the following multivariate RR among men in the highest quintile of intake compared with those in the lowest: magnesium, 0.71 (95% CI, 0.56 to 0.89; P = 0.01 for trend); potassium, 0.54 (95% CI, 0.42 to 0.68; P < 0.001 for trend); and fluid, 0.71 (95% CI, 0.59 to 0.85; P < 0.001 for trend). Animal protein was associated with risk only in men with a body mass index <25 kg/m(2) (RR, 1.38; 95% CI, 1.05 to 1.81; P = 0.03 for trend). Sodium, phosphorus, sucrose, phytate, vitamin B(6), vitamin D, and supplemental calcium were not independently associated with risk. In conclusion, the association between calcium intake and kidney stone formation varies with age. Magnesium intake decreases and total vitamin C intake seems to increase the risk of symptomatic nephrolithiasis. Because age and body size affect the relation between diet and kidney stones, dietary recommendations for stone prevention should be tailored to the individual patient.

Topics: Adult; Aged; Ascorbic Acid; Calcium, Dietary; Dietary Proteins; Follow-Up Studies; Humans; Incidence; Kidney Calculi; Magnesium; Male; Middle Aged; Nutrition Assessment; Potassium, Dietary; Risk Factors; Surveys and Questionnaires

Since the incidence of renal calculi in the South African black population is extremely rare while in white subjects it occurs at the same rate as elsewhere in the western world, we investigated the possibility that different renal handling mechanisms in response to different dietary challenges might occur in the 2 race groups.. We administered 5 different dietary protocols, including low calcium, high oxalate, vitamin C, high salt and lacto-vegetarian, to 10 healthy male subjects from each race group. We collected 24-hour urine at baseline and after 4 days on the prescribed diet which were analyzed for biochemical and physicochemical risk factors. Dietary intake was controlled throughout the experimental period. A 24-hour dietary recall questionnaire was recorded at baseline and analyzed using food composition tables. Statistical analysis of variance was performed on all the data.. The low calcium diet caused statistically significant changes only in black subjects, which consisted of urinary oxalate increase (0.17 to 0.23 mmol./24 hours, p = 0.01), relative supersaturation of calcium oxalate decrease (1.88 to 0.97, p = 0.03) and relative supersaturation of brushite increase (0.85 to 1.69, p = 0.03). The high oxalate diet caused statistically significant changes in both race groups but these changes were different in the 2 groups. In white subjects urinary pH increased (6.24 to 6.62, p = 0.01), potassium excretion increased (40.01 to 73.49, p = 0.01) and relative supersaturation of brushite increased (1.34 to 2.12, p = 0.05). In black subjects urinary citrate increased (1.94 to 2.99 mmol./24 hours, p = 0.01). Clinically unimportant changes occurred in both race groups after the other 3 diets.. Renal handling of dietary calcium and oxalate in South African black and white subjects is different and may explain the different stone incidence in the 2 race groups.

Topics: Adolescent; Adult; Ascorbic Acid; Black People; Calcium Oxalate; Calcium, Dietary; Diet; Diet, Vegetarian; Humans; Kidney; Kidney Calculi; Male; Oxalates; Racial Groups; Risk Factors; Sodium, Dietary; White People

Oxalate generation at pH-values above 5.0 and an oxalate-protein binding in acidified plasma would appear to complicate the determination of oxalate in plasma.. To avoid complex sample preparation we used a high-performance liquid chromatographic system with an inline enzyme reactor (HPLC-ER) containing immobilised oxalate oxidase. The detection limit was 0.68 micromol/l. Blood was drawn in lithium-heparin vessels and immediately centrifuged at 4 degrees C. The yielded plasma was ultrafiltered using a Centrisart-I-tube. To inhibit oxalate generation by ascorbic acid, the ultrafiltrate was acidified with 1 mol/l hydrochloric acid during ultrafiltration at 4 degrees C. The liquid thus yielded was used for HPLC-ER analysis. Blood samples were obtained from 133 healthy adults (63 men, 70 women, aged 20-94 years) with no history of renal disorder and from 79 patients (53 men, 26 women, aged 19-77 years) with a history of calcium oxalate stone formation.. Mean plasma oxalate was 2.65 +/- 2.31 micromol/l for healthy subjects and 4.21 +/- 0.56 micromol/l for stone formers.. Analysis yielded no significant differences between males and females. A correlation between age and plasma oxalate was found for the healthy adults (p < 0.001).

Topics: Adult; Aged; Aged, 80 and over; Ascorbic Acid; Calcium Oxalate; Chromatography, High Pressure Liquid; Enzymes, Immobilized; Female; Humans; Indicators and Reagents; Kidney Calculi; Male; Middle Aged; Oxalates; Oxidoreductases; Protein Binding; Ultrafiltration

Topics: Ascorbic Acid; Dietary Supplements; Female; Humans; Kidney Calculi; Male; Oxalates; Risk Factors

Concern has been raised that high levels of ascorbic acid consumption may lead to potential adverse effects, such as vitamin B12 deficiency, iron overload, and kidney stones.. To examine the relation of serum ascorbic acid level, which reflects intake, to serum vitamin B12 level, serum ferritin level, and kidney stones.. We analyzed data collected on a random sample of the US population enrolled in the Second National Health and Nutrition Examination Survey, 1976-1980. We analyzed data using linear and logistic regression models. Serum ascorbic acid, serum vitamin B12, hemoglobin, red blood cell mean corpuscular volume (MCV), and serum ferritin levels were measured using standardized protocols. History of kidney stones was determined by self-report.. After multivariate adjustment, serum ascorbic acid level was associated with higher serum vitamin B12 levels among women in regression models that assumed a linear relationship; each 57-pmol/L (1.0-mg/dL) increase in serum ascorbic acid level (range, 6-153 micromol/L [0.1 to 2.7 mg/dL]) was independently associated with a serum vitamin B12 level increase of 60 pmol/L (81 pg/ mL) (P<.001). Among men, serum ascorbic acid level was marginally associated with higher serum vitamin B12 levels: each 57-micromol/L (1.0-mg/dL) increase in serum ascorbic acid level was associated with a serum vitamin B12 level increase of 27 pmol/L (36 pg/mL) (P = .10). In addition, serum ascorbic acid level was not associated with correlates of vitamin B12 deficiency, such as higher MCV levels, macrocytosis (MCV >100), or lower hemoglobin concentrations. Serum ascorbic acid level was not independently associated with serum ferritin levels. However, among women only, serum ascorbic acid levels were associated in a nonlinear fashion with prevalence of elevated serum ferritin levels (P = .02). We found no association between serum ascorbic acid level and prevalence of kidney stones in women or men (both P>.05).. Serum ascorbic acid levels were not associated with decreased serum vitamin B12 levels (or indicators of vitamin B12 deficiency), prevalence of kidney stones, serum ferritin levels, or-among men-prevalence of elevated serum ferritin levels. Serum ascorbic acid levels were associated with prevalence of elevated serum ferritin levels among women. Although the clinical relevance of these findings is uncertain, it seems prudent to suggest that women with a genetic susceptibility to iron overload should consider moderating their intake of ascorbic acid.

Topics: Adult; Aged; Ascorbic Acid; Female; Ferritins; Humans; Iron Overload; Kidney Calculi; Linear Models; Logistic Models; Male; Middle Aged; Prevalence; Sex Factors; United States; Vitamin B 12; Vitamin B 12 Deficiency

Urinary oxalate is an important determinant of calcium oxalate kidney stone formation. High doses of vitamin B6 may decrease oxalate production, whereas vitamin C can be metabolized to oxalate. This study was conducted to examine the association between the intakes of vitamins B6 and C and risk of kidney stone formation in women. The relation between the intake of vitamins B6 and C and the risk of symptomatic kidney stones were prospectively studied in a cohort of 85,557 women with no history of kidney stones. Semiquantitative food-frequency questionnaires were used to assess vitamin consumption from both foods and supplements. A total of 1078 incident cases of kidney stones was documented during the 14-yr follow-up period. A high intake of vitamin B6 was inversely associated with risk of stone formation. After adjusting for other dietary factors, the relative risk of incident stone formation for women in the highest category of B6 intake (> or =40 mg/d) compared with the lowest category (<3 mg/d) was 0.66 (95% confidence interval, 0.44 to 0.98). In contrast, vitamin C intake was not associated with risk. The multivariate relative risk for women in the highest category of vitamin C intake (> or =1500 mg/d) compared with the lowest category (<250 mg/d) was 1.06 (95% confidence interval, 0.69 to 1.64). Large doses of vitamin B6 may reduce the risk of kidney stone formation in women. Routine restriction of vitamin C to prevent stone formation appears unwarranted.

Topics: Adult; Age Distribution; Ascorbic Acid; Cohort Studies; Confidence Intervals; Data Collection; Female; Humans; Incidence; Kidney Calculi; Middle Aged; Multivariate Analysis; Oxalates; Prospective Studies; Pyridoxine; Risk Assessment; United States

The present study was undertaken to determine the effect of ingestion of large doses of vitamin C on urinary oxalate excretion and on a number of other biochemical and physicochemical risk factors associated with calcium oxalate urolithiasis. A further objective was to determine urinary ascorbate excretion and to relate it qualitatively to ingested levels of the vitamin and oxalate excretion. Ten healthy males participated in a protocol in which 4 g ascorbic acid was ingested for 5 days. Urines (24 h) were collected prior to, during and after the protocol. The urine collection procedure was designed to allow for the analysis of oxalate in the presence and absence of an EDTA preservative and for the analysis of ascorbic acid by manual titration using 2,6 dichlorophenolindophenol. Physicochemical risk factors such as the calcium oxalate relative supersaturation and Tiselius risk index were calculated from urine composition. The results showed that erroneously high analytical oxalate levels occur in the asence of preservative. In the preserved samples there was no significant increase in oxalate excretion at any stage of the protocol. Ascorbate excretion increased when vitamin C ingestion commenced but levelled out after 24 hours suggesting that saturation of the metabolic pool is reached within 24 hours after which ingested ascorbic acid is excreted unmetabolized in the urine. While transient statistically significant changes occurred in some of the biochemical risk factors, they were not regarded as being clinically significant. There were no changes in either the calcium oxalate relative supersaturation or Tiselius risk index. It is concluded that ingestion of large doses of ascorbic acid does not affect the principal risk factors associated with calcium oxalate kidney stone formation.

Topics: 2,6-Dichloroindophenol; Adult; Ascorbic Acid; Calcium Oxalate; Humans; Kidney Calculi; Male; Risk Factors; South Africa

Long-term or high-dosage consumption of vitamin C may play a role in calcium oxalate kidney stone formation. The present study was undertaken to determine the biochemical and physicochemical risk factors in a male subject who developed haematuria and calcium oxalate crystalluria after ingestion of large doses of ascorbic acid for 8 consecutive days.. Twenty-four-hour urine samples were collected before and during the ascorbic acid ingestion period as well as after the detection of haematuria. A special procedure was implemented for urine collections to allow for oxalate, ascorbate and other urinalysis. Oxalate was determined in the presence of EDTA to prevent in vitro conversion to ascorbic acid, whereas ascorbate itself was determined by manual titration in a redox method using the dye dichlorophenolindophenol. Urinalysis data were used to compute calcium oxalate relative supersaturations and Tiselius risk indices, whereas scanning electron microscopy was used to examine urinary deposits.. Oxalate excretion increased by about 350% during ascorbate ingestion before haematuria. Ascorbate concentrations also increased dramatically but appeared to reach a plateau maximum. Increasing calcium excretion was accompanied by decreasing potassium and phosphate values. The calcium oxalate relative supersaturation and Tiselius risk index increased during vitamin C ingestion and large aggregates of calcium oxalate dihydrate crystals were observed by scanning electron microscopy immediately after the detection of haematuria.. High percentage metabolic conversion of ascorbate to oxalate in this subject caused relative hyperoxaluria and crystalluria, the latter manifesting itself as haematuria. Clinicians need to be alerted to the potential dangers of large dose ingestion of vitamin C in some individuals.

Topics: Adult; Ascorbic Acid; Calcium Oxalate; Crystallization; Hematuria; Humans; Hyperoxaluria; Kidney Calculi; Male; Microscopy, Electron, Scanning; Risk Factors; Time Factors

Topics: Ascorbic Acid; Attitude of Health Personnel; Bias; Dietary Supplements; Evidence-Based Medicine; Health Knowledge, Attitudes, Practice; Humans; Intermittent Claudication; Kidney Calculi; Micronutrients; Quackery; United States; Vitamin E

A kinetic method for the determination of vitamin C, citrate and oxalate in their mixture is described. The method involves the use of cerium(IV) as an oxidant and measurement of reaction rates spectrophotometrically by following the decrease in absorbance of cerium(IV) at 410 nm. The adaptive Kalman filter was used for data manipulation and analysis. It is shown that the use of the Kalman filter is superior to the classical differential kinetic methods owing to its suitability for the determination of analytes that react with a single reagent and exhibit a reaction rate constant ratio of less than 1.5. The results obtained were found to be highly precise and accurate even in the presence of some expected interferents.

Topics: Absorption; Algorithms; Ascorbic Acid; Citrates; Humans; Kidney Calculi; Oxalates

The association between the intake of vitamins C and B6, and kidney stone formation was examined.. We conducted a prospective study of the relationship between the intake of vitamins C and B6 and the risk of symptomatic kidney stones in a cohort of 45,251 men 40 to 75 years old with no history of kidney calculi. Vitamin intake from foods and supplements was assessed using a semiquantitative food frequency questionnaire completed in 1986.. During 6 years of followup 751 incident cases of kidney stones were documented. Neither vitamin C nor vitamin B6 intake was significantly associated with the risk of stone formation. For vitamin C the age-adjusted relative risk for men consuming 1,500 mg. daily or more compared to less than 250 mg. daily was 0.78 (95% confidence interval 0.54 to 1.11). For vitamin B6 the age-adjusted relative risk for men consuming 40 mg. daily or more compared to less than 3 mg. daily was 0.91 (95% confidence interval 0.64 to 1.31). After adjusting for other potential stone risk factors the relative risks did not change significantly.. These data do not support an association between a high daily intake of vitamin C or vitamin B6 and the risk of stone formation, even when consumed in large doses.

Topics: Ascorbic Acid; Cohort Studies; Diet; Energy Intake; Health Personnel; Humans; Incidence; Kidney Calculi; Male; Middle Aged; Prospective Studies; Pyridoxine; Risk Factors; Time Factors; United States

Topics: Acute Disease; Acute Kidney Injury; Adenocarcinoma; Anuria; Ascorbic Acid; Humans; Infusions, Intravenous; Kidney Calculi; Male; Middle Aged; Oxalates; Prostatic Neoplasms

Topics: Ascorbic Acid; Calcium Oxalate; Humans; Kidney Calculi; Risk Factors

Two sets of animal experiments using guinea pigs were planned to evaluate the effect of ascorbic acid supplementation on the lithogenic process. In the first set of experiments, 10, 40, and 60 mg doses of ascorbic acid/100g body weight/day were given for 105 days. Neither of the ascorbic acid doses given induced crystalluria, calcification or stone formation, thereby confirming our previous findings that ascorbic acid in the doses used by clinicians does not cause urolith formation. In the second set of experiments, ascorbic acid was supplemented in hypercalciuric (induced by calcium carbonate feeding) and hyperoxaluric (induced by sodium oxalate feeding) animals for 45 days. The results indicated that it exacerbated the calcification process in renal and bladder tissue.

Topics: Animals; Ascorbic Acid; Calcium; Carboxylic Acids; Creatinine; Guinea Pigs; Hydrogen-Ion Concentration; Kidney; Kidney Calculi; Magnesium; Male; Mucoproteins; Phosphorus; Uric Acid; Urinary Bladder; Urinary Bladder Calculi; Uromodulin

Drug-induced urinary calculi are rarely observed. However, it is useful to know this etiology. A complete anamnesis of drugs and dosages is mandatory if a patient presents with lithiasis, since some pharmacotherapies may carry an enhanced lithogenic risk. The list of lithogenic drugs is discussed. In order to yield preventive data, infrared, spectrophotometry is the best available analytic method.

Topics: Allopurinol; Antacids; Ascorbic Acid; Calcium; Cathartics; Ceftriaxone; Humans; Kidney Calculi; Medical History Taking; Quinolones; Substance-Related Disorders; Sulfonamides

Administration of ascorbic acid, at 150 mg/100 ml of water intake, for one month, induced hyperoxaluria in the rats (P less than 0.001) and decreased citraturia (P less than 0.001) magnesuria (P less than 0.001) and pyrophosphaturia (P less than 0.01). The same disorders were observed when the dose administered was 300 mg/100 ml, excepted that oxaluria was considerably enhanced in this group. Despite these variations, renal deposits were not observed, even in the animals receiving 300 mg of ascorbate/100 ml of water intake. This protection was due to decreased calcium excretion (P less than 0.01 in two groups) and probably to acidification of the urine.

Topics: Animals; Ascorbic Acid; Calcium; Citrates; Citric Acid; Diphosphates; Drug Evaluation, Preclinical; Kidney Calculi; Magnesium; Male; Oxalates; Oxalic Acid; Rats; Rats, Inbred Strains

The daily intake of 103 recurrent idiopathic calcium stone formers and 146 controls was assessed by means of a computer-assisted 24-h dietary record. Timed 24-h urine samples were collected over the same period to assess the relationship between dietary intake of nutrients and urinary risk factors for calcium stones. After standardisation for sex, age and social status a total of 128 subjects underwent final statistical analysis; 64 renal stone formers and 64 controls. Significant increases in the consumption of animal and vegetable protein and purine were identified as the nutritional factors that distinguished renal stone formers from controls. As expected, the daily urinary excretion of calcium and oxalate was higher and the daily urinary excretion of citrate was lower in stone formers than in controls. No difference with respect to daily urinary uric acid excretion was recorded. Daily urinary excretion of calcium was correlated to dietary protein intake while daily urinary oxalate was correlated to dietary vitamin C intake. It was concluded that renal stone formers could be predisposed to stones because of their dietary patterns. A link between the protein content of the diet and urinary calcium was confirmed, but dietary animal protein had a minimal effect on oxalate excretion.

Topics: Adult; Aged; Ascorbic Acid; Calcium; Diet; Dietary Proteins; Female; Humans; Kidney Calculi; Male; Middle Aged; Nitrogen; Oxalates; Risk Factors; Socioeconomic Factors

The effects of ammonium chloride, methenamine hippurate and ascorbic acid on urinary pH was studied in 14 normal subjects. A statistically significant reduction of urinary pH was recorded with ammonium chloride in daily doses of 1.5 and 3 g, but not with 2 g of methenamine hippurate or 1.8 g of ascorbic acid. Long-term treatment with ammonium chloride in doses between 1.5 and 3 g was given to 11 patients in order to reduce the risk of new stone formation or growth of fragments remaining after disintegration of infected renal stones. Biochemical stone analyses showed struvite in 9 of the treated stones, and urine cultures verified the presence of urease-producing bacteria in 10 patients. Apart from ammonium chloride, the patients were treated with antibiotics, in 4 patients continuously and in the others during periods from 2 to 34 months. The patients were followed for an average period of 32 months. No adverse reactions were recorded with the dosage used. Initially, 6 patients were stone-free, whereas 5 had residual stone fragments with a largest diameter ranging from 4 to 20 mm. At follow-up, 2 patients were still stone-free, and of 5 patients with residual fragments 1 showed stable disease and 3 an improved stone situation. In 5 patients, 3 of whom had residual stone fragments, antibiotic treatment had been interrupted without infectious relapse.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Ammonium Chloride; Anti-Infective Agents, Urinary; Ascorbic Acid; Female; Hippurates; Humans; Hydrogen-Ion Concentration; Kidney Calculi; Male; Methenamine; Middle Aged; Recurrence; Time Factors; Urinary Tract Infections; Urine

Topics: Ascorbic Acid; Chronic Disease; Humans; Iodohippuric Acid; Kidney; Kidney Calculi; Organotechnetium Compounds; Pyelonephritis; Radioisotope Renography

The dietary habits of renal calcium stone patients were investigated both by dietary history and by 4-day food records and compared with the dietary habits of control subjects, matched on the basis of age, sex, social and professional status. The method using 4-day records seemed to be more precise, judged by the correlation to the urinary output of nutrients. There was no difference in the daily intake of major nutrients between stone formers and controls, but a higher ingestion of vitamin C in controls and a larger consumption of alcohol among stone formers. In contrast to some epidemiological evidence, there were no significant differences in consumption of animal protein when stone formers were matched for social class. Despite a similar total intake of calcium, the stone formers excreted more calcium in the urine, probably reflecting a higher intestinal absorption of calcium. There seem to be only marginally different dietary habits between stone formers and carefully matched control subjects. Differences in the urinary output of minerals and electrolytes are mainly due to variations in gastrointestinal uptake.

Topics: Adult; Alcohol Drinking; Ascorbic Acid; Calcium; Diet; Eating; Female; Humans; Kidney Calculi; Male; Middle Aged

Studies in 24 recurrent oxalate stone-formers have shown that values for urinary calcium excretion for this group on at-home diets vary significantly (P less than 0.001) more than values for creatinine excretions. By placing stone-formers on controlled in-hospital diets and measuring their calcium excretions, we were able to predict probable outpatient hypercalciuria (greater than 7.5 mmol/day) with a sensitivity of 95% and a specificity of 95%. In this study, the renal loss of calcium during low-calcium diets was proportional to the absorptive hypercalciuria during high-calcium diets. Calcium loading experiments in fasted stone-formers and normal subjects indicated that citrate, at citrate:calcium molar ratios ranging from 0.12 to 1, stimulated urinary calcium excretion more than did calcium carbonate loading alone. In addition, citrate also significantly (P less than 0.05) increased the excretion of urinary oxalate by two normal subjects for a given load of calcium oxalate. Malabsorption of citrate and possibly other hydroxycarboxylic acids may thus predispose to oxalate nephrolithiasis by promoting calcium and oxalate absorption.

Topics: Absorption; Adult; Ascorbic Acid; Calcium; Calcium Oxalate; Calcium, Dietary; Citrates; Citric Acid; Female; Humans; Kidney Calculi; Kinetics; Male; Middle Aged; Oxalates; Oxalic Acid

Although cystine stones account for 1 to 3 per cent of renal calculi, many of these patients are difficult to manage because of recurrent urolithiasis. Seven cases of homozygous cystinuria are summarized. The evolution to the present treatment of percutaneous extraction and chemolysis appears to be the preferred form of treatment although extracorporeal shock wave lithotripsy (ESWL) may also be utilized. In addition, in vitro experiments were conducted to study the effectiveness of different chelating agents and buffers at different urinary pHs. The effect of cystinuric and noncystinuric urines was also evaluated.

Topics: Acetylcysteine; Adult; Ascorbic Acid; Bicarbonates; Cystine; Cystinuria; Female; Homozygote; Humans; Kidney Calculi; Male; Middle Aged; Penicillamine; Sodium; Sodium Bicarbonate; Tromethamine

Neither stone nor calcium oxalate crystal deposition was observed in the kidneys of rats after oral ingestion of 60 mg. L-ascorbic acid daily for three months, although urinary excretion of stone inhibitors (magnesium and citrate) was decreased and oxalate increased. The highly acidic pH of urine and reduced calcium excretion might have prevented their deposition.

Topics: Animals; Ascorbic Acid; Calcium Oxalate; Kidney Calculi; Male; Rats

An investigation of variables important to calcium stone formation in urine indicated significantly increased daily excretion of calcium and oxalate and decreased excretion of ascorbate and citrate by recurrent calcium stone formers. In addition, urine volume, sodium, mucopolysaccharide, and protein were also significantly increased. We compared the uptake of citrate and ascorbate from the gut into the blood in normal controls and stone formers. These studies indicated significantly depressed absorption of both these hydroxycarboxylic acids in recurrent calcium stone formers. We also found that concurrent administration of citrate inhibited ascorbate absorption and increased urinary oxalate excretion after an ascorbate load in normal subjects and stone formers. These findings suggest a mechanism that explains hyperoxaluria in stone patients on the basis of a malabsorption of citrate, ascorbate, and possibly other hydroxycarboxylic acids.

Topics: Absorption; Adult; Ascorbic Acid; Calcium; Citrates; Citric Acid; Female; Humans; Kidney Calculi; Malabsorption Syndromes; Male; Middle Aged; Oxalates; Oxalic Acid; Sodium; Urine

Studies of recurrent stone formers indicated that they have significantly increased urinary oxalate and decreased ascorbate excretions. Results of oral and intravenous administration of ascorbate indicate an enhanced production of oxalate from ascorbate in recurrent calcium stone formers as compared with normal persons and that most of this oxalate is generated in the gut.

Topics: Adult; Ascorbic Acid; Calcium Oxalate; Female; Humans; Kidney Calculi; Male; Middle Aged; Oxalates; Time Factors; Urinary Calculi

We report a case of a large staghorn calculus of the right kidney that was treated with sulfamethoxazole and trimethoprim, and amiloride-hydrochlorothiazide. The patient, who had refused any surgical intervention, also elected to take ascorbic acid. Without any other treatment x-rays revealed dissolution of the staghorn calculus 8 weeks later.

Topics: Aged; Amiloride; Ascorbic Acid; Drug Combinations; Drug Therapy, Combination; Female; Humans; Hydrochlorothiazide; Kidney Calculi; Radiography; Sulfamethoxazole

Topics: Animals; Ascorbic Acid; Calcium Oxalate; Glycosaminoglycans; Kidney Calculi; Male; Rats; Uric Acid

A scintigraphic study of the kidneys was carried out in 1780 patients with chronic pyelonephritis: 1308 with calculous and 472 with acalculous pyelonephritis. The scintigraphic finding was interpreted for each kidney separately. Diffuse damages of renal parenchyma was most often observed (47,6%), being, in the majority of the cases--bilateral. Disturbed drainage was established in 13,2%, dysfunction of one of the kidneys--in 18,8% and focal disturbed structure--in 5,4% of the kidneys studied. The results from the scintigraphic study were juxtaposed to the clinic of the disease and the data from laboratory and X-ray investigations. The scintigraphic study of the kidneys with 99m Tc-ascorbic complex is easy to perform, well tolerated by the patients, non-invasive method with no special risks, with minimal irradiation loading. Scintigraphy provides valuable information to the clinicians about the functional, structural and drainage disorders in the kidneys of patients with chronic pyelonephritis, allowing the control of the evolution of the disease and the effect of the treatment.

Topics: Ascorbic Acid; Chronic Disease; Humans; Kidney; Kidney Calculi; Organotechnetium Compounds; Pyelonephritis; Radionuclide Imaging; Technetium

The amount of oral ascorbic acid that a patient can tolerate without diarrhea, increases somewhat proportionately to the "toxicity" of his disease. Clinically, in a disease ameliorated by ascorbate, there is a suppression of symptoms only with very high doses and approximately to that extent which a nonrate-limited, antioxidant free radical scavenger, might be expected to affect that disease process if all harmful free radicals and highly reactive oxidizing substances were quenched. In most pathologic processes, the rate at which free radicals and highly reactive oxidants are produced, exceeds the rate at which the ordinary rate-limited antioxidant free radical scavenging mechanisms can quench those free radicals and oxidants. When ascorbate acts as a scavenger, dehydroascorbate is formed; but if the ascorbate/dehydroascorbate (AA/DHA) ratio is kept high (the redox potential kept reducing) until the unstable dehydroascorbate undergoes hydrolysis or can be reduced back to ascorbate, the dehydroascorbate will do no harm. Since even at very high doses, ascorbate is virtually nontoxic, it may be given in the enormous doses necessary to quench almost all unwanted free radicals and oxidants. The wide spectrum of infectious diseases ameliorated by massive doses of ascorbate indicates some common pathologic processes in these diseases.

Topics: Acquired Immunodeficiency Syndrome; Antioxidants; Ascorbic Acid; Ascorbic Acid Deficiency; Diarrhea; Dose-Response Relationship, Drug; Free Radicals; Glucosephosphate Dehydrogenase Deficiency; Humans; Infant; Kidney Calculi; Kinetics; Oxidation-Reduction; Scurvy; Sudden Infant Death

The diets of 51 men with renal stones were compared with those of 94 age-matched controls, using a measured record of all food and drink consumed during 4 days. The mean intakes of three nutrients suspected in the aetiology of renal stones, animal protein, refined carbohydrate (sugar) and dietary fibre, were similar for both cases and controls. However, the cases had a higher intake of ascorbic acid. A greater proportion of cases had low fluid intakes or took no exercise in their leisure time.

Topics: Adult; Ascorbic Acid; Diet; Dietary Carbohydrates; Dietary Fiber; Dietary Proteins; Drinking; Humans; Kidney Calculi; Male; Middle Aged; Physical Exertion

Topics: Ascorbic Acid; Diet; Humans; Kidney Calculi

We report on our experience with 9 cystine-lithiasis patients who were treated with large doses of ascorbic acid (5 g/day) for periods ranging from 6-27 months. We observed recidive lithogenesis in only 3 patients during this time. The influence of ascorbic acid on the excretion of cystine and oxalate in the urine is discussed. A lack of side effects and the significantly lower frequency of recidivation justify the further use of ascorbic as an alternative medication in cystine lithiasis.

Topics: Adult; Ascorbic Acid; Cystine; Cystinuria; Dose-Response Relationship, Drug; Female; Humans; Kidney Calculi; Male; Middle Aged; Oxalates; Oxalic Acid; Recurrence; Urinary Bladder Calculi; Urinary Calculi

Topics: Ascorbic Acid; Calcium Oxalate; Diet; Gastrointestinal Diseases; Glycine; Glyoxylates; Humans; Intestinal Absorption; Kidney Calculi; Oxalates

The effect of ascorbic acid on the serum and urinary uric acid was studied in 14 subjects. Two to 6 h after the ingestion of 4.0 g of ascorbic acid, the fractional clearance of uric acid increased to 202% +/- 41% of the control value. This uricosuria was inhibited by pyrazinamide and by low-dose acetylsalicylic acid, but was not accompanied by an increase of the creatinine clearnace. Ascorbic acid did not diminish protein-bound uric acid. In 3 subjects who ingested 8.0 g of ascorbic acid for 3 to 7 days the serum uric acid decreased by 1.2 to 3.1 mg/dl as a result of a sustained uricosuria. These results suggest that ascorbic acid could invalidate studies involving the measurement of uric acid and obscure the diagnosis of gout in some cases. Theoretically it could precipitate attacks of gouty arthritis or renal calculi in predisposed persons. These observations show a pharmacologic effect of megadoses of a simple vitamin.

Topics: Ascorbic Acid; Aspirin; Female; Humans; Kidney; Kidney Calculi; Male; Models, Biological; Pyrazinamide; Uric Acid

Topics: Acidosis; Ascorbic Acid; Blood; Cholesterol; Gastrointestinal Diseases; Glycosuria; Humans; Hydrogen-Ion Concentration; Hyperglycemia; Kidney Calculi; Oxalates; Prothrombin; Vitamin B 12

Topics: Adult; Aged; Aneurysm; Ascorbic Acid; Female; Glomerular Filtration Rate; Humans; Hydronephrosis; Hypertension, Renal; Iodine Radioisotopes; Iodohippuric Acid; Isotope Labeling; Kidney; Kidney Calculi; Kidney Diseases, Cystic; Kidney Neoplasms; Male; Middle Aged; Pyelonephritis; Quality Control; Radioisotope Renography; Renal Artery; Renal Artery Obstruction; Technetium; Urinary Calculi

Topics: Ascorbic Acid; Female; Humans; Infertility, Female; Kidney Calculi

Topics: Ascorbic Acid; Humans; Kidney Calculi; Oxalates

Topics: Ascorbic Acid; Aspirin; Asthma; Calcium; Citrates; Coronary Disease; Depression, Chemical; Diabetes Mellitus; Duodenal Ulcer; Dwarfism, Pituitary; Emphysema; Facial Paralysis; Gluconates; Histamine H1 Antagonists; Humans; Hypertension; Hyperthyroidism; Kidney Calculi; Liver Diseases, Parasitic; Magnesium; Oxalates; Phosphates; Pyridoxine; Schistosomiasis; Stimulation, Chemical; Terpenes; Tuberculosis, Pulmonary