Association of Dietary Acid Load and Depression among Iranian Women: A Case-Control Study

Abstract

Background: The present study aimed to investigate the association between dietary acid load and depression among Iranian women. Methods: This case–control study was conducted on 110 women with depression and 220 healthy controls recruited from two psychiatric clinics in Tehran, Iran. Dietary intake over the previous 12 months was assessed using a validated semi-quantitative food frequency questionnaire (FFQ) consisting of 168 items. Dietary acid load was calculated using two established indices: Potential Renal Acid Load (PRAL) and Net Endogenous Acid Production (NEAP). The association between dietary acid load and depression was evaluated using multivariate logistic regression models in crude and adjusted analyses. The adjusted model was controlled for potential confounders, including energy, physical activity, history of depression, smoking status, periods of unemployment, occupational status, and body mass index (BMI). Results: Participants in the highest quartile of PRAL and NEAP had significantly higher odds of depression compared to those in the lowest quartile. In the fully adjusted model, the odds ratio (OR) for depression was 3.52 (95 CI: 1.64–7.54; P for trend <0.001) for PRAL and 4.07 (95 CI: 1.86–8.89; P for trend <0.001) for NEAP. Conclusion: Higher dietary acid load, as measured by PRAL and NEAP, was associated with increased odds of depression in women. However, due to the case–control design, causal inferences cannot be established. Further prospective studies are warranted to confirm these findings. © 2026 Shahid Sadoughi University of Medical Sciences. All rights reserved.