Estimates of renal net acid excretion and their relationships with serum uric acid and hyperuricemia in a representative German population sample.

Background/objective: Preliminary interventional data suggest that a reduction of dietary acid load raises renal uric acid excretion and decreases serum uric acid (SUA). In line with this, in a recent cross-sectional analysis of a representative adult population sample, a higher potential renal acid load (PRAL) was found to associate with higher SUA levels. Against this background, we re-examined the relationship of the body's acid load with SUA and hyperuricemia using nutrition-derived estimates of renal net acid excretion (NAE).

Subjects/methods: Cross-sectional analyses were performed in n = 6894 participants (18-79 y) of the German Health Interview and Examination Survey for Adults (DEGS1). Two different approaches were used to estimate NAE, one based on the sum of food frequency questionnaire (FFQ)-derived PRAL and body-surface area-derived organic acids (eNAE) and the other based on FFQ-derived protein and potassium intake ratios (eNAE). The associations of eNAE and eNAE with SUA were analyzed in multiple linear regression models. Multiple logistic regressions were used to calculate odds ratios (OR) for hyperuricemia comparing higher (T3) and lower (T1) tertiles of the NAE estimates.

Results: After adjusting for relevant confounders, eNAE (p = 0.0048) and eNAE (p = 0.0023) were positively associated with SUA. In addition, participants with a higher eNAE or eNAE had higher ORs for having hyperuricemia (OR: 1.73, 95% CI: 1.24-2.40, OR: 1.51, 95% CI: 1.10-2.08, respectively).

Conclusion: The results substantiate findings of a previous analysis that dietary acid load is a potential influencing factor on SUA. This implicates that a lower dietary acid load may have beneficial effects on SUA.