Associations Between Vitamin C Intake and Serum Uric Acid in US Adults: Findings from National Health and Nutrition Examination Survey 2011-2016

Backgrounds: 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.

Methods: 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.

Results: 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).

Conclusions: 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.