Dietary Acid Load and Kidney Stones: NEAP Shows a Positive Association in a Nationally Representative Sample

This study aimed to examine the associations of Dietary acid load ( DAL ), estimated by net endogenous acid production ( NEAP ) and potential renal acid load ( PRAL ), with the prevalence of kidney stones in US adults. We analyzed 26,468 adults aged ≥ 20 years from NHANES 2007–2018. NEAP and PRAL were calculated from the average of two 24‐h dietary recalls. The outcome was self‐reported history of kidney stones. Survey‐weighted multivariable logistic regression estimated ORs and 95% CIs . Restricted cubic splines evaluated potential nonlinear patterns. The weighted prevalence of kidney stones was 9.6%. In fully adjusted models, participants in the highest NEAP quartile had higher odds of kidney stones than those in the lowest quartile ( OR 1.32, 95% CI 1.06–1.65; p = 0.015). Spline analyses indicated a significant overall association, while the formal test for nonlinearity was not significant; the curve visually suggested an inflection around NEAP ≈40.6 mEq /day. PRAL showed a borderline association after full adjustment, but did not reach conventional statistical significance ( Q4 vs. Q1 OR 1.21, 95% CI 1.00–1.47; p = 0.054). Results were generally consistent across demographic and clinical subgroups and in sensitivity analyses. In this cross‐sectional study of a nationally representative sample, higher NEAP was associated with higher odds of kidney stones, whereas PRAL did not show a clear association after full adjustment. These findings should be interpreted as associations rather than evidence of causality. The apparent inflection near ~40 mEq /day should be considered hypothesis‐generating. Prospective studies are needed to clarify temporality, minimize reverse causation, and determine potential clinical relevance.