The association between dietary acid load and Kidney/Liver function in morbidly obese bariatric candidates

Emerging evidence indicates that dietary acid load (DAL) may influence metabolic health, including renal and hepatic functions. However, studies explicitly examining the relationship between DAL and biomarkers of renal and hepatic functions among morbidly obese individuals undergoing bariatric surgery are scarce. This study aimed to investigate associations between dietary acid load indices, Potential Renal Acid Load (PRAL), Net Endogenous Acid Production (NEAP), and DAL and renal (serum creatinine, eGFR) and hepatic biomarkers (ALT, AST, ALP) in this population. In this cross-sectional study, we assessed the dietary intake of 369 morbidly obese patients awaiting bariatric surgery, with a mean age of 39.4 years (± 10.0) and a mean BMI of 45.5 kg/m² (± 6.1). A validated food frequency questionnaire was used for this assessment. We calculated dietary acid load indices and examined their associations with renal and hepatic biomarkers. Multiple linear regression models were employed for analysis, adjusting for age, sex, BMI, education, physical activity, smoking, type 2 diabetes, hypertension, triglycerides, HDL-C, total energy intake, saturated fat, and dietary fiber intake. Higher dietary acid load scores (PRAL, NEAP, DAL) were consistently associated with increased serum creatinine (P = 0.01). No significant associations were observed with eGFR. Elevated dietary acid load indices were also significantly correlated with higher ALT (P < 0.05) and AST (P = 0.01) levels, suggesting hepatocellular dysfunction. No significant associations were found between ALP and dietary acid load indices. Higher dietary acid load is associated with impaired renal and hepatocellular biomarkers among morbidly obese individuals preparing for bariatric surgery. Reducing the dietary acid load may be an effective nutritional strategy to optimize preoperative renal and hepatic health. Prospective intervention studies are warranted to confirm these associations and elucidate the underlying mechanisms.