Dietary acid load and risk of hypertension: the Rotterdam Study1–3

Background: Mild metabolic acidosis, which can be caused by diet, may result in elevated blood pressure (BP). Objective: The objective was to examine whether dietary acid load was associated with incident hypertension in a cohort of older Dutch adults from the Rotterdam Study. Design: The analyses included 2241 participants aged 55 y who were free of hypertension at baseline (1990–1993) and who had complete dietary and BP data. Dietary data were ob-tained from a 170-item food-frequency questionnaire. We used 2 measures to characterize dietary acid load: 1) potential renal acid load (PRAL) by using an algorithm including protein, phos-phorus, potassium, calcium, and magnesium, and 2) estimated net endogenous acid production (NEAP) based on protein and potassium. HRs for 6-y incidence of hypertension were obtained in tertiles of PRAL and NEAP with adjustment for age, sex, BMI, smoking, education, and intakes of alcohol, fiber, and total energy. Results: We identified 1113 incident cases of hypertension dur-ing 8707 person-years of follow-up. The median dietary acid load ranged from 214.6 to 19.9 mEq/d across categories of PRAL. Hypertension risk was not significantly associated with dietary acid load. The multivariate HRs (95 % CIs) in consecu-tive tertiles of PRAL were 1.00 (reference), 1.01 (0.87, 1.17), and 1.02 (0.88, 1.18) (P trend = 0.83). The median dietary acid loads were 30.4, 36.7, and 43.7 mEq/d, respectively, in consec-utive tertiles of NEAP. Corresponding HRs for NEAP were 1.00 (reference), 0.92 (0.80, 1.07), and 0.94 (0.81, 1.10) (P-trend = 0.46). Conclusion: The findings from this prospective cohort study pro-vided no evidence of an association between dietary acid load and risk of hypertension in older adults. Am J Clin Nutr doi: 10. 3945/ajcn.111.022343