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.
Level 4 - case-series / case-control
Cross-sectional survey without longitudinal follow-up
PubMed 15641075 · doi:10.1002/art.20761
What was done
Researchers analyzed cross-sectional data from 14,809 adults (6,932 men and 7,877 women, aged 20 and older) from the Third National Health and Nutrition Examination Survey (NHANES III, 1988–1994). Dietary intake of purine-rich foods, total protein, and dairy products was evaluated using a food-frequency questionnaire. Multivariate linear regression evaluated associations with serum uric acid levels, adjusting for age, sex, total energy intake, body mass index, alcohol intake, serum creatinine, self-reported gout and hypertension, and use of diuretics, beta-blockers, allopurinol, and uricosuric agents.
What was found
Serum uric acid levels increased with meat and seafood consumption and decreased with dairy consumption. Age-adjusted differences between extreme quintiles of intake were: 0.48 mg/dL for total meat (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). These differences remained statistically significant after multivariate adjustment (P < 0.05 for all comparisons). Milk consumption of 1 or more times per day was associated with lower uric acid levels compared to non-consumption (multivariate difference -0.25 mg/dL, 95% CI -0.40, -0.09; P < 0.001 for trend), as was yogurt consumption of at least once every other day (multivariate difference -0.26 mg/dL, 95% CI -0.41, -0.12; P < 0.001 for trend). Total protein intake was not associated with serum uric acid levels (P = 0.74 for trend).
Why it matters
This study provides large-scale, population-level evidence that meat and seafood intakes are positively associated with serum uric acid levels, while dairy products are inversely associated. It also clarifies that total protein intake is not associated with hyperuricemia.
Limits
The cross-sectional design prevents causal inference. Dietary intake was self-reported via a food-frequency questionnaire, which is susceptible to measurement error and recall bias. Residual confounding from unmeasured dietary or lifestyle factors remains possible.
Cited by
- supports Organ meats, sardines, and scallops are high sources of purines that metabolize into uric acid.