Acid-producing diets have been associated with adverse health conditions. Dietary acid load can be estimated from dietary intake data, but the available methods require a full dietary assessment. We sought to identify a simpler means to estimate 24-h urinary net acid excretion (NAE), a robust measure of net endogenous acid production, using self-reported intakes of fruits, vegetables (acid-neutralizing foods), grain and/or protein (acid-producing foods) acquired by two different methods in community-dwelling older adults. Identifying food groups associated with NAE by using a method not requiring a full diet assessment could have a broad clinical application.SUBJECTS/METHODS:
Fruit, vegetable, protein and grain servings/day were estimated with a widely used food frequency questionnaire (study A, n = 162, 63 ± 8 years). Differences in their intakes across NAE categories (< 5, ≥ 5 to < 15, ≥ 15 to < 50, ≥ 50 milliequivalents (mEq)/day) were analyzed using analysis of variance. The findings were verified in a second study, which estimated dietary intakes, using a more detailed record-assisted 24-h recall (study B, n = 232, 67 ± 6 years).RESULTS:
Fruit intake was significantly associated with NAE in both studies. In study A, fruit intake was 9% lower with each categorical NAE increase (unstandardized beta = -0.21, P = 0.01) and 7% lower with each categorical NAE increase in study B (unstandardized beta = -0.18; P = 0.02). Grain intake was positively associated with NAE in study B only (unstandardized beta = +0.14; P = 0.01). Vegetable and protein intake were not associated with NAE in either study.CONCLUSIONS:
The inverse association between fruit intake and NAE suggests low self-reported fruit intake may be an indicator of acid-producing diets in older adults.