Higher dietary acid load is weakly associated with higher adiposity measures and blood pressure in Japanese adults: The National Health and Nutrition Survey

Epidemiologic evidence on the associations between dietary acid load and metabolic risk factors is limited and inconsistent. We investigated the hypothesis that dietary acid load is associated with adverse profiles of metabolic risk factors in Japanese adults. This cross-sectional study included 15 618 Japanese adults aged ≥20 years from the 2012 National Health and Nutrition Survey, Japan. Dietary acid load was characterized as potential renal acid load (PRAL) and net endogenous acid production (NEAP) based on information on nutrient intake, which was derived from a 1-day semi-weighed dietary record. After adjustment for potential confounding factors, both PRAL and NEAP were positively associated with body mass index (BMI) and waist circumference in both sexes (P for trend ≤.01). PRAL and NEAP also showed positive associations with systolic and diastolic blood pressure in men, independently of BMI (P for trend ≤.005), while they showed positive associations with systolic (but not diastolic) blood pressure in women (P for trend ≤.03). For other metabolic risk factors, there were positive associations between PRAL and NEAP and total cholesterol and LDL-cholesterol concentrations only in men (P for trend ≤.04). After excluding participants taking medication for hypertension, dyslipidemia, and diabetes, similar associations were observed for adiposity measures and blood pressure (P for trend ≤.01), with there being positive associations between NEAP and HDL-cholesterol and between PRAL and NEAP and glycated hemoglobin in men (P for trend ≤.04). In conclusion, higher dietary acid load was significantly but weakly associated with higher adiposity measures and blood pressure in Japanese adults.