Background: Diets high in acid load may contribute to kidney function impairment. This study aimed to investigate the association between dietary acid load and 1-year changes in glomerular filtration rate (eGFR) and urine albumin/creatinine ratio (UACR).
Methods: Older adults with overweight/obesity and metabolic syndrome (mean age 65 ± 5 years, 48% women) from the PREDIMED-Plus study who had available data on eGFR (n = 5,874) or UACR (n = 3,639) at baseline and after 1 year of follow-up were included in this prospective analysis. Dietary acid load was estimated as potential renal acid load (PRAL) and net endogenous acid production (NEAP) at baseline from a food frequency questionnaire. Linear and logistic regression models were fitted to evaluate the associations between baseline tertiles of dietary acid load and kidney function outcomes. One year-changes in eGFR and UACR were set as the primary outcomes. We secondarily assessed ≥ 10% eGFR decline or ≥10% UACR increase.
Results: After multiple adjustments, individuals in the highest tertile of PRAL or NEAP showed higher one-year changes in eGFR (PRAL, β: -0.64 ml/min/1.73 m2; 95% CI: -1.21 to -0.08 and NEAP, β: -0.56 ml/min/1.73 m2; 95% CI: -1.13 to 0.01) compared to those in the lowest category. No associations with changes in UACR were found. Participants with higher levels of PRAL and NEAP had significantly higher odds of developing ≥10% eGFR decline (PRAL, OR: 1.28; 95% CI: 1.07-1.54 and NEAP, OR: 1.24; 95% CI: 1.03-1.50) and ≥10 % UACR increase (PRAL, OR: 1.23; 95% CI: 1.04-1.46) compared to individuals with lower dietary acid load.
Conclusions: Higher PRAL and NEAP were associated with worse kidney function after 1 year of follow-up as measured by eGFR and UACR markers in an older Spanish population with overweight/obesity and metabolic syndrome.
Keywords: albuminuria; chronic kidney disease (CKD); dietary acid load; glomerular filtration rate (GFR); kidney function; net endogenous acid production (NEAP); potential renal acid load (PRAL); renal nutrition.
Copyright © 2022 Valle-Hita, Becerra-Tomás, Díaz-López, Vázquez-Ruiz, Megías, Corella, Goday, Martínez, Alonso-Gómez, Wärnberg, Vioque, Romaguera, López-Miranda, Estruch, Tinahones, Lapetra, Serra-Majem, Bueno-Cavanillas, Tur, Martín-Sánchez, Pintó, Gaforio, Matía-Martín, Vidal, Amengual-Galbarte, Daimiel, Ros, García-Arellano, Barragán, Fitó, Peña-Orihuela, Asencio-Aznar, Gómez-Gracia, Martinez-Urbistondo, Morey, Casas, Garrido-Garrido, Tojal-Sierra, Damas-Fuentes, Goñi, Ortega-Azorín, Castañer, Garcia-Rios, Gisbert-Sellés, Sayón-Orea, Schröder, Salas-Salvadó and Babio.