ascorbic-acid and Hyperuricemia

Gout, known as "the disease of the kings", is the most frequent type of arthritis. It results from sustained hyperuricemia that leads to monosodium urate crystal deposition in joint structures and soft tissue. Environmental factors such as diet affect the incidence of gout; there is a known relationship between the occurrence of an acute attack of gout and the consumption of alcohol and meat; and a low purine diet is a widely recognized nonpharmacological method of supplementing the treatment and preventing recurrence of arthritis. This review aims to summarize the current knowledge about the role of vitamin C in prevention and treatment of gout. A PubMed/Medline database search on the role of vitamin C in purine metabolism was done. Reports from in vitro and animal studies seem to be promising and to allow explanation of the physiological relationship between vitamin C and uric acid. Most epidemiological studies indicate a significant correlation between high vitamin C intake and lower serum uric acid levels. Despite promising observations, there are few observational and interventional studies, and their results do not clearly define the benefits of a high daily intake of vitamin C in preventing the development and recurrence of gout.

Topics: Ascorbic Acid; Diet; Gout; Humans; Hyperuricemia

The consumption of fructose has gained increased attention as a potential cause of hyperuricaemia since fructose metabolism produces urate as a byproduct. In addition to sucrose and high fructose corn syrup, fresh fruits also contain fructose, suggesting that patients with hyperuricaemia or gout might also avoid fresh fruit. However, the effect of fruits is complex. Some studies reported that fruit intake was associated with gout flares while other studies showed that fruits rather lowered the risk for gout. Thus, fruits should not be simply viewed as a source of fructose. The complexity of fruits is accounted for by several nutrients existing in fruits. Vitamin C, epicatechin, flavonols, potassium and fibre are all nutrients in fruits, and these factors could modify fructose and urate effects. In this review, we discuss clinical studies evaluating the effect of fruit and fruit juice intake on hyperuricaemia and gout, and propose potential mechanisms for how fruit may influence urate levels.

Topics: Ascorbic Acid; Dietary Fiber; Fructose; Fruit; Fruit and Vegetable Juices; Gout; Humans; Hyperuricemia; Prunus avium; Uric Acid

Gout is an inflammatory arthritis caused by deposition of monosodium urate crystals within synovial joints. Although it is most well-known for its arthritis, gout has an intimate relationship with many other cardiovascular and metabolic conditions. Current recommendations support aggressive medical therapy to treat gout, whereas dietary counseling has become less emphasized. This article argues for the absolute importance of dietary counseling in gout and proves why this counseling may impact the long term well-being of a patient with gout.

Topics: Alcohol Drinking; Ascorbic Acid; Carbonated Beverages; Coffee; Dairy Products; Diet Therapy; Disease Progression; Gout; High Fructose Corn Syrup; Humans; Hyperuricemia; Metabolic Syndrome; Purines; Tea; Vitamins

To assess the effect of vitamin C supplementation on serum uric acid (SUA) by pooling the findings from published randomized controlled trials (RCTs).. A total of 2,082 publications identified through systematic search were subjected to the following inclusion criteria: 1) RCTs conducted on human subjects, 2) reported end-trial SUA means and variance, 3) study design with oral vitamin C supplementation and concurrent control groups, and 4) trial duration of at least 1 week. Trials that enrolled children or patients receiving dialysis were excluded. Two investigators independently abstracted trial and participant characteristics. SUA effects were pooled by random-effects models and weighted by inverse variance.. Thirteen RCTs were identified in the Medline, EMBase, and Cochrane Central Register of Controlled Trials databases. The total number of participants was 556, the median dosage of vitamin C was 500 mg/day, trial size ranged from 8-184 participants, and the median study duration was 30 days. Pretreatment SUA values ranged from 2.9-7.0 mg/dl (Système International d'Unités [SI units]: 172.5-416.4 μmoles/liter). The combined effect of these trials was a significant reduction in SUA of -0.35 mg/dl (95% confidence interval -0.66, -0.03 [P = 0.032]; SI units: -20.8 μmoles/liter). Trial heterogeneity was significant (I(2) = 77%, P < 0.01). Subgroup analyses based on trial characteristics indicated larger reductions in uric acid in trials that were placebo controlled.. In aggregate, vitamin C supplementation significantly lowered SUA. Future trials are needed to determine whether vitamin C supplementation can reduce hyperuricemia or prevent incident and recurrent gout.

Topics: Administration, Oral; Adolescent; Adult; Aged; Aged, 80 and over; Ascorbic Acid; Biomarkers; Dietary Supplements; Down-Regulation; Evidence-Based Medicine; Female; Humans; Hyperuricemia; Male; Middle Aged; Randomized Controlled Trials as Topic; Uric Acid; Young Adult

Hmong men in Minnesota exhibit a high prevalence of gout and hyperuricemia. Although evidence of vitamin C's effectiveness as a treatment for gout is mixed, analysis of therapeutic benefit based on an individual's multiomic signature may identify predictive markers of treatment success.. The primary objective of the Hmong Microbiome ANd Gout, Obesity, Vitamin C (HMANGO-C) study was to assess the effectiveness of vitamin C on serum urate in Hmong adults with and without gout/hyperuricemia. The secondary objectives were to assess if 1) vitamin C impacts the taxonomic and functional patterns of microbiota; 2) taxonomic and functional patterns of microbiota impact vitamin C's urate-lowering effects; 3) genetic variations impact vitamin C's urate-lowering effects; 4) differential microbial biomarkers exist for patients with or without gout; and 5) there is an association between obesity, gut microbiota and gout/hyperuricemia.. This prospective open-labelled clinical trial was guided by community-based participatory research principles and conducted under research safety restrictions for SARS-CoV-2. We aimed to enroll a convenient sample of 180 Hmong adults (120 with gout/hyperuricemia and 60 without gout/hyperuricemia) who provided medical, demographic, dietary and anthropometric information. Participants took vitamin C 500mg twice daily for 8 weeks and provided pre-and post- samples of blood and urine for urate measurements as well as stool samples for gut microbiome. Salivary DNA was also collected for genetic markers relevant to uric acid disposition.. We expected to quantify the impact of vitamin C on serum urate in Hmong adults with and without gout/hyperuricemia. The outcome will enhance our understanding of how gut microbiome and genomic variants impact the urate-lowering of vitamin C and associations between obesity, gut microbiota and gout/hyperuricemia. Ultimately, findings may improve our understanding of the causes and potential interventions that could be used to address health disparities in the prevalence and management of gout in this underserved population.. ClinicalTrials.gov NCT04938024 (first posted: 06/24/2021).

Topics: Adult; Ascorbic Acid; Clinical Trials, Phase II as Topic; COVID-19; Gout; Gout Suppressants; Humans; Hyperuricemia; Male; Microbiota; Obesity; Prospective Studies; SARS-CoV-2; Uric Acid; Vitamins

Clinical studies have shown that oral vitamin C supplementation can reduce serum uric acid levels in multiple populations and may also improve acute mountain sickness. However, it is unclear whether this protocol can improve high-altitude hyperuricemia. Therefore, we aimed to evaluate the role of vitamin C supplementation on high-altitude hyperuricemia.. A preliminary prospective control study was performed in 2015. Young male army recruits (n = 66), who had recently arrived on the Tibetan Plateau for the first time, were recruited for study I. Subjects were assigned to either the vitamin C group, who took an oral daily dose of 500 mg vitamin C for 1 month, or the blank control group, who had no intervention. The levels of serum uric acid, serum creatinine, and blood urea nitrogen were monitored at baseline and at the end of 1 month. In a second study II in 2016 (n = 120), the effect of 500 mg/d vitamin C on high-altitude hyperuricemia was compared with 75 IU/d of vitamin E.. In study I, the level of serum uric acid at 1 month was significantly higher than at baseline (436.1 ± 79.3 μmol/L vs. 358.0 ± 79.8 μmol/L, p < 0.001) and the prevalence of hyperuricemia was also significantly higher (63.6% [95% confidence interval, CI: 52.0%-75.2%] vs. 19.7% [95% CI: 10.1%-29.3%], p < 0.001). Both the level of serum uric acid (411.5 ± 74.2 μmol/L vs. 460.8 ± 54.8 μmol/L, p = 0.003) and the prevalence of hyperuricemia (48.5% [95% CI: 31.4%-65.6%] vs. 78.8% [95% CI: 64.9%-92.7%], p = 0.020) were significantly lower in the vitamin C group than in the blank control group. In study II, the levels of serum uric acid and the frequency of hyperuricemia also increased over 1 month and were similar in the vitamin C and the vitamin E groups at both baseline and 1 month (p > 0.05). The change in serum uric acid was positively correlated with both the changes in serum creatinine (r = 0.599, p < 0.001) and blood urea nitrogen (r = 0.207, p = 0.005).. These findings indicate that healthy young men develop an increase in serum uric acid within a month of moving from low to high altitude. Oral vitamin C supplementation can safely reduce this increase at a low cost.

Topics: Adolescent; Altitude; Ascorbic Acid; Blood Urea Nitrogen; Creatinine; Dietary Supplements; Humans; Hyperuricemia; Male; Pilot Projects; Treatment Outcome; Uric Acid; Vitamin E; Vitamins; Young Adult

Clinical studies of recent years have shown that hyperuricemia is associated with poor outcomes such as cardiovascular mortality and dialysis inadequacy in patients undergoing hemodialysis. Our study investigated the effect of vitamin C supplementation on serum uric acid levels in hemodialysis patients.. This randomized placebo-controlled trial was conducted on 172 hemodialysis patients. They were randomly divided into the intervention group, to receive 250 mg of vitamin C, three times per week, for 8 weeks, and control groups 1 and 2, to receive placebo injection (saline) and no intervention, respectively. Serum levels of uric acid and creatinine were measured at the start of the study and also after 8 weeks.. The mean of serum levels of uric acid was 6.02 ± 1.08 mg/dL (reference range, 2.6 mg/dL to 6 mg/dL). Nearly, half of the patients (46.7%) had a serum level of uric acid greater than 6 mg/dL. The median baseline serum levels of uric acid were 6.2 mg/dL, 5.9 mg/dL, and 6 mg/dL in the intervention, control 1, and control 2 groups, respectively (P = .19). After 2 months, median levels reduced significantly in the vitamin C group to 5.8 mg/dL as compared to 6.4 mg/dL and 6.3 mg/dL in control groups (P = .02). The mean serum creatinine level had no significant changes during the study.. Our results demonstrated the existence of a significant negative relationship between vitamin C and serum uric acid levels. Detailed investigations with larger sample sizes and longer-term use of vitamin C are recommended.

Topics: Adult; Aged; Aged, 80 and over; Ascorbic Acid; Creatinine; Dietary Supplements; Female; Humans; Hyperuricemia; Kidney Failure, Chronic; Male; Middle Aged; Renal Dialysis; Treatment Outcome; Uric Acid; Vitamins; Young Adult

Diet rich in purines may increase the serum level of uric acid causing hyperuricemia, contributing to learning and memory to impairments. Ascorbic acid has a potent antioxidant potential. The hippocampus is a pivotal component of human brains and other vertebrates that plays crucial roles in the consolidation of information and spatial memory. Our study was mainly designated to examine the potential palliative role of ascorbic acid supplements on harmful effects induced hyperuricemia on the hippocampus of albino Wistar rats.. Forty rats were subgrouped into the control group, ascorbate-only group, hyperuricemic group, and combined hyperuricemia and ascorbate group.. Ascorbic acid has strongly preserved the histological architecture and maintained the normal hippocampal functions in the hyperuricemic group.. The anti-inflammatory and antioxidant properties of ascorbic acid could protect the hippocampus of albino Wistar rats against the hazardous impact of hyperuricemia.

Topics: Animals; Antioxidants; Ascorbic Acid; Hippocampus; Humans; Hyperuricemia; Rats; Rats, Wistar

Dietary factors has been found to influence serum uric acid (SUA) levels. We further explored the associations between dietary and supplemental vitamin C intake and SUA in a large population-based study.. The cross-sectional study included 6308 participants (3146 males and 3162 females) aged ≥20 years from the National Health and Nutrition Examination Survey (NHANES) 2011-2016 in the United States. The dietary vitamin C was log-transformed for statistical analysis. Hyperuricemia was defined as SUA concentrations >420 umol/L in males or >360 umol/L in females. The associations of dietary vitamin C and supplemental vitamin C with SUA levels and hyperuricemia risk were evaluated using weighted linear regression models and weighted multivariate logistic regression models, and a subgroup analysis stratified by gender was also conducted.. In this large-scale database study, there was a negative association between dietary vitamin C (log transformed) and SUA levels in US adults (β = -7.27, 95% CI: -11.58, -2.97). The inverse relationship existed among males but not females (P for interaction = 0.02). There was inverse correlation between dietary vitamin C (log transformed) and hyperuricemia risk (OR = 0.68, 95% CI: 0.57, 0.81), especially in males compared to females determined through an interaction test (P = 0.04). There were no associations between supplemental vitamin C and SUA levels (β = 1.00 (95% CI: -4.44, 6.44) or hyperuricemia risk (OR = 0.98 (95% CI: 0.78, 1.24). High-dosage supplemental vitamin C (>300 mg) and hyperuricemia risk were not associated (OR = 1.04, 95% CI: 0.69, 1.56).. This study demonstrated that there were negative associations between dietary vitamin C and SUA levels and hyperuricemia risk among US adults. The inverse correlations between dietary vitamin C and hyperuricemia risk were more significant in males compared to females. There were no associations between supplemental vitamin C and SUA levels or hyperuricemia risk.

Topics: Adult; Ascorbic Acid; Cross-Sectional Studies; Female; Humans; Hyperuricemia; Male; Nutrition Surveys; Risk Factors; United States; Uric Acid; Vitamins

Hyperuricemia contributes to chronic kidney disease development. However, it has been historically viewed with limited research interest. In this study, we mimicked the development of hyperuricemic nephropathy by using a potassium oxonate-induced hyperuricemia rat model. We found that administering vitamin C at 10 mg/kg/day effectively ameliorated hyperuricemic nephropathy. Compared to the control group, rats with hyperuricemia had significantly increased serum uric acid level, xanthine oxidase activity, and urine microalbumin level, by 5-fold, 1.5-fold, and 4-fold, respectively. At the same time, vitamin C supplementation reverted these values by 20% for serum uric acid level and xanthine oxidase activity and 50% for microalbumin level. Vitamin C also alleviated renal pathology and decreased the expression of pro-inflammatory and pro-fibrotic markers. A further mechanistic study suggested that vitamin C might attenuate hyperuricemic nephropathy in renal tubular epithelial cells induced by monosodium urate (MSU) crystal, at least in part, by directly inhibiting IL-6/JAK2/STAT3 signaling pathway. Meanwhile, in macrophages, vitamin C inhibited the expression of TGF-β, and reduced ROS level induced by MSU by about 35%. In short, our results suggest that vitamin C supplementation delay the progression of hyperuricemic nephropathy.

Topics: Animals; Antioxidants; Ascorbic Acid; Fibrosis; Hyperuricemia; Inflammation; Kidney Diseases; Male; Oxonic Acid; Rats; Rats, Sprague-Dawley

A high fructose intake has been shown to be associated with increased serum urate concentration, whereas ascorbate (vitamin C) may lower serum urate by competing with urate for renal reabsorption.. We assessed the combined association, as the fructose:vitamin C intake ratio, and the separate associations of dietary fructose and vitamin C intakes on prevalent hyperuricemia.. We conducted cross-sectional analyses of dietary intakes of fructose and vitamin C and serum urate concentrations among Jackson Heart Study participants, a cohort of African Americans in Jackson, Mississippi, aged 21-91 y. In the analytic sample (n = 4576), multivariable logistic regression was used to examine the separate associations of dietary intakes of fructose and vitamin C and the fructose:vitamin C intake ratio with prevalent hyperuricemia (serum urate ≥7 mg/dL), after adjusting for age, sex, smoking, waist circumference, systolic blood pressure, estimated glomerular filtration rate, diuretic medication use, vitamin C supplement use, total energy intake, alcohol consumption, and dietary intake of animal protein. Analyses for individual dietary factors (vitamin C, fructose) were adjusted for the other dietary factor.. In the fully adjusted model, there were 17% greater odds of hyperuricemia associated with a doubling of the fructose:vitamin C intake ratio (OR: 1.17; 95% CI: 1.08, 1.28), 20% greater odds associated with a doubling of fructose intake (OR: 1.20; 95% CI: 1.08, 1.34), and 13% lower odds associated with a doubling of vitamin C intake (OR: 0.87; 95% CI: 0.78, 0.97). Dietary fructose and the fructose:vitamin C intake ratio were more strongly associated with hyperuricemia among men than women (P-interaction ≤ 0.04).. Dietary intakes of fructose and vitamin C are associated with prevalent hyperuricemia in a community-based population of African Americans.

Topics: Adult; Aged; Aged, 80 and over; Ascorbic Acid; Black or African American; Cross-Sectional Studies; Diet; Dietary Sugars; Energy Intake; Feeding Behavior; Female; Fructose; Humans; Hyperuricemia; Logistic Models; Male; Middle Aged; Mississippi; Nutritional Status; Odds Ratio; Risk Factors; Sex Factors; Uric Acid; Young Adult

Gout is the most common form of inflammatory arthritis and is caused by hyperuricaemia. Some studies have found a reduction in plasma urate with vitamin C supplementation. We tested the hypothesis that high plasma vitamin C is causally associated with low plasma urate and low risk of hyperuricaemia, using a Mendelian randomization approach.. We measured plasma urate and genotyped for the SLC23A1 rs33972313 vitamin C variant in 106 147 individuals from the Copenhagen General Population Study, of which 24 099 had hyperuricaemia. We measured plasma vitamin C in 9234 individuals and genotyped for the SLC2A9 rs7442295 urate variant in 102 345 individuals.. Each 10 µmol/l higher plasma vitamin C was associated with a -2.3(95%CI: -0.69 to -3.9) µmol/l lower plasma urate after multivariable adjustments. The SLC23A1 rs33972313 GG genotype was associated with a 9% (5.6%, 11.9%) higher plasma vitamin C compared with AA and AG combined but was not associated with plasma urate (P = 0.31). Likewise, for each 10 µmol/l higher plasma vitamin C the odds ratios for hyperuricaemia were 0.92 (0.86, 0.98) observationally after multivariable adjustments, but 1.01 (0.84, 1.23) genetically.. High plasma vitamin C was associated with low plasma urate and with low risk of hyperuricaemia. However, the SLC23A1 genetic variant causing lifelong high plasma vitamin C was not associated with plasma urate levels or with risk of hyperuricaemia. Thus, our data do not support a causal relationship between high plasma vitamin C and low plasma urate.

Topics: Adult; Aged; Aged, 80 and over; Ascorbic Acid; Female; Genetic Variation; Genotype; Humans; Hyperuricemia; Male; Mendelian Randomization Analysis; Middle Aged; Odds Ratio; Overnutrition; Risk Factors; Uric Acid; Young Adult

The aim of this study was to determine the association between vitamin C intake and risk of hyperuricemia or serum uric acid levels in male and female subjects in the Korean Multi-Rural Communities Prospective Cohort.. This cross-sectional analysis was conducted in 9400 subjects enrolled in the Korean Multi-Rural Communities Cohort Study. The risk of hyperuricemia was assessed in five quintiles (Q1 to Q5) according to dietary and total vitamin C intake using multivariate-adjusted logistic regression models. Relationships between serum uric acid levels and vitamin C intake were evaluated using linear regression analysis after adjustment for covariates. Information about dietary components was collected using validated food frequency questionnaires.. Dietary vitamin C intake, but not total vitamin C intake, was significantly different between hyperuricemic and non-hyperuricemic subjects in males (P=0.01) and females (P=0.02). The risk of hyperuricemia decreased with increased dietary vitamin C intake in male and female subjects after multivariate adjustment (P for trend=0.002 in males and P for trend=0.02 in females). An effect of total vitamin C intake on hyperuricemia risk was identified in females (P for trend=0.04), but not males (P for trend=0.06). Serum uric acid level was linearly associated with total vitamin C intake in females (β=-0.0001, P=0.01), but not with dietary vitamin C intake in either gender.. This study showed that vitamin C intake might be in part responsible for hyperuricemia or serum uric acid level in the Korean Multi-Rural Communities Cohort.

Topics: Aged; Ascorbic Acid; Cohort Studies; Cross-Sectional Studies; Female; Humans; Hyperuricemia; Male; Middle Aged; Republic of Korea; Risk Factors; Rural Population; Uric Acid

Topics: Ascorbic Acid; Dietary Supplements; Female; Humans; Hyperuricemia; Male; Uric Acid; Vitamins

Topics: Ascorbic Acid; Dietary Supplements; Female; Humans; Hyperuricemia; Male; Randomized Controlled Trials as Topic; Uric Acid

Determination of the relative contribution of uric acid level increases to the total measured antioxidative activity could be very useful for testing antioxidative products and their effect on human health. The aim of this report is to present a simple spectrophotometric method that combines the measurement of total antioxidative capacity of a sample by ferric reducing/antioxidative power (FRAP) assay, with the uricase-reaction (specific elimination of uric acid), in order to establish and correct for the contribution of uric acid in FRAP values. We measured FRAP values, with (uric acid-independent antioxidant capacity, TAC-UA) and without (total antioxidant capacity, TAC) uricase treatment, and expressed it as μmol/L of uric acid equivalents. In such way, it was possible to determine both total and uric acid-independent antioxidant capacity, plasma uric acid (UA, as the difference between TAC and TAC-UA), and the ratio of the uric acid in total antioxidant capacity (UA/TAC).

Topics: Antioxidants; Ascorbic Acid; Humans; Hyperuricemia; Oxidation-Reduction; Spectrophotometry; Urate Oxidase; Uric Acid

We examined associations between vitamin C intake and serum uric acid in men in a population-based study.. We included 1387 men without hypertension and with body mass index (BMI) < 30 kg/m(2) in the Health Professional Follow-up Study. Dietary intake was assessed with a semiquantitative food frequency questionnaire validated for use in this population. Serum uric acid concentrations were measured.. Greater intakes of total vitamin C were significantly associated with lower serum uric acid concentrations, after adjustment for smoking, BMI, ethnicity, blood pressure, presence of gout, use of aspirin, and intake of energy, alcohol, dairy protein, fructose, meat, seafood and coffee. An inverse dose-response association was observed through vitamin C intake of 400-500 mg/day, and then reached a plateau. Adjusted mean uric acid concentrations across total vitamin C intake categories (< 90, 90-249, 250-499, 500-999, or > or = 1000 mg/day) were 6.4, 6.1, 6.0, 5.7, and 5.7 mg/dl, respectively (p for trend < 0.001). Greater vitamin C intake was associated with lower prevalence of hyperuricemia (serum uric acid > 6 mg/dl). Multivariate odds ratios for hyperuricemia across total vitamin C intake categories were 1 (reference), 0.58, 0.57, 0.38, and 0.34 (95% CI 0.20-0.58; P for trend < 0.001). When we used dietary data, which were assessed 4-8 years before blood collection, as predictors, we observed similar inverse associations between vitamin C intake and uric acid.. These population-based data indicate that vitamin C intake in men is inversely associated with serum uric acid concentrations. These findings support a potential role of vitamin C in the prevention of hyperuricemia and gout.

Topics: Adult; Aged; Antioxidants; Ascorbic Acid; Diet Surveys; Feeding Behavior; Gout; Humans; Hyperuricemia; Male; Middle Aged; Prospective Studies; Risk Factors; Surveys and Questionnaires; United States; Uric Acid