Carbohydrate Intake and Its Association With Dietary Acid Load in U.S. Adults: Results From a Cross-Sectional Study

Abstract

Background: The safety profile of low-carbohydrate diets is controversial and poorly understood. We investigated the effects of low-moderate carbohydrate intake on dietary acid load (DAL), an emerging health risk factor and novel clinical marker associated with numerous adverse clinical outcomes. Methods: We used data from the National Health and Nutrition Examination Surveys to investigate how low-moderate carbohydrate intake quantitatively affects DAL (as assessed by PRAL and NEAP scores) and to contrast the results to DAL scores in individuals that meet carbohydrate intake recommendations. Results: We analyzed data from 23 825 individuals, of which 4891 consumed a low-moderate carbohydrate diet. Said individuals derived 37.84% of energy from carbohydrates, tended to be male, had a mean BMI of 28.47 kg/m², and consumed significantly more energy from fat and protein (P≤.01 for both) than individuals that met carbohydrate recommendations Low-moderate carbohydrate intake was associated with a significantly higher DAL. Mean PRAL_R, NEAP_R, and NEAP_F values were 26.12, 71.02, and 68.98 mEq/d, respectively. Multivariate regression revealed the highest DAL scores in individuals on a low-carbohydrate diet, obtaining <26% of energy from carbohydrates. Conclusions: Low-moderate carbohydrate intake is associated with increased DAL scores, which has been repeatedly associated with various health repercussions.

Keywords: dietary acid load; low-carbohydrate diet; net endogenous acid production; nutrition; potential renal acid load.

Figure 1.

Participant inclusion flow chart.

Figure 2.

Contribution (%) of macronutrients to daily energy intake: a comparison between individuals restricting carbohydrates (cases, blue) and individuals not restricting carbohydrates (controls, red).

Figure 3.

Plot of marginal predicted values based on the regression model, illustrating differences in the linear relationship of DAL and age, depending on carbohydrate intake. The sample includes n = 142 individuals on low-carbohydrate diet, n = 4749 on a moderate carbohydrate diet and n = 18 934 individuals that did not restrict carbohydrate intake.