Dietary Acid Load and Glomerular Filtration Rate in Chronic Kidney Disease

Background: Kidney diseases are prevalencing rapidly. The nutritional transition has caused the diet of Iran community to increase the dietary acid load (DAL) and thus exacerbate metabolic disorders. Therefore, our goal was to determine the DAL of the diet in patients with Chronic Kidney Disease (CKD). Methods: In this cross-sectional study, the study population was composed of 90 patients with renal insufficiency. DAL was included of Potential Renal Acid Load(PRAL), Net EndogeneusAcid Production(NEAP) and Net Acid Excretion(NAE) that were extracted using data of food frequency questionnaire and their correlation with anthropometric and biochemical indices such as Glomerular Filtration Rate (GFR) and creatinine were analyzed by SPSS v.26 software with a significance level of < 0.05. Results: Mean of dietary acid load of participants were 17.15±9.85,-8.7±0.35 and 59.04±10.9 mEq/day for PRAL, NEAP and NAE respectively. Daily intake of energy (P<0.001) and protein percent of energy (P<0.01) in third tertile (T 3 ) of PRAL were significant higher than first tertile (T 1 ). Mean of age (P<0.05) and blood creatinine concentration (P<0.01) were significant higher in T 1 than T 1 of NEAP index and GFR was significant low (P<0.05). Daily energy intake (p<0.05), blood calcium concentration (p<0.05) and GFR (p<0.05) were significantly more in higher tertiles of NAE index. Based on Crude General linear model, the higher tertiles of PRAL compared to first tertile had significant lower GFR (P<0.05). In adjustment model, T3 group had more not significant GFR than T 1 group. Only in model II adjustment, T 2 group of NAE compared to T 1 , had higher GFR. Mean difference of GFR did not significant across tertiles of NEAP index. In case of Creatinine, based on model I adjustment, T3 group of NAE had more creatinine concentration than T 1 group (P<0.01). T3 group of NEAP than T 1 group had significant lower creatinine in crude and modelI adjustment (P<0.01). Discussion: Dietary Acid Load was associated with kidney function in CKD patients. In order to obtain logical results and to understand the cause-and-effect relationships, long-term studies with larger populations and consideration of blood factors such as blood bicarbonate are recommended.