Intake of purine-rich foods, protein, and dairy products and relationship to serum levels of uric acid - The Third National Health and Nutrition Examination Survey

Objective. Various commonly consumed foods have long been suspected of affecting the serum uric acid level, but few data are available to support or refute this impression. Our objective was to evaluate the relationship between dietary factors and serum uric acid levels in a nationally representative sample of men and women in the US. Methods. Using data from 14,809 participants (6,932 men and 7,877 women) ages 20 years and older in the Third National Health and Nutrition Examination Survey (for the years 1988-1994), we examined the relationship between the intake of purine-rich foods, protein, and dairy products and serum levels of uric acid. Diet was assessed with a food-frequency questionnaire. We used multivariate linear regression to adjust for age, sex, total energy intake, body mass index, use of diuretics, beta-blockers, allopurinol, and uricosuric agents, self-reported hypertension and gout, serum creatinine level, and intake of alcohol. Results. The serum uric acid level increased with increasing total meat or seafood intake and decreased with increasing dairy intake. After adjusting for age, the differences in uric acid levels between the extreme quintiles of intake were 0.48 mg/dl for total meat (95% confidence interval [95% CI] 0.34, 0.61; P < 0.001 for trend), 0.16 mg/dl for seafood (95% CI 0.06, 0.27; P = 0.005 for trend), and -0.21 mg/dl for total dairy intake (95% CI -0.37, -0.04; P = 0.02 for trend). After adjusting for other covariates, the differences between the extreme quintiles were attenuated but remained significant (P < 0.05 for all comparisons). The total protein intake was not associated with the serum uric acid level in multivariate analyses (P = 0.74 for trend). Those who consumed milk 1 or more times per day had a lower serum uric acid level than did those who did not drink milk (multivariate difference -0.25 [95% CI -0.40, -0.09]; P < 0.001 for trend). Similarly, those who consumed yogurt at least once every other day had a lower serum uric acid level than did those who did not consume yogurt (multivariate difference -0.26 [95% CI -0.41, -0.12]; P < 0.001 for trend). Conclusion. These findings from a nationally representative sample of adults in the US suggest that higher levels of meat and seafood consumption are associated with higher serum levels of uric acid but that total protein intake is not. Dairy consumption was inversely associated with the serum uric acid level.