A recent research published on Nephrology Dialysis Transplantation sheds light on the impact on plant and animal protein intake on renal function in older women. The study assessed the dietary intake from a validated food frequency questionnaire and the estimated glomerular filtration rate (eGFR) (using the Chronic Kidney Disease Epidemiology Collaboration creatinine and cystatin C equation) at baseline, 5 and 10 years in the Longitudinal Study of Aging Women cohort. The association between plant- and animal-sourced protein intake and kidney function was tested using linear mixed modeling.

      A total of 1374 Caucasian women [mean (standard deviation, SD) age = 75 years (2.7) and mean (SD) baseline eGFR = 65.6 mL/min/1.73 m2 (13.1)] were selected for the analysis. The average decline in eGFR was 0.64 mL/min/1.73 m2/year [95% confidence interval (CI) 0.56–0.72]. Higher intakes of plant-sourced protein were associated with slower declines in eGFR after adjusting for covariates including animal protein and energy intake (P = 0.03). For each 10 g of plant protein, the yearly decline in eGFR was reduced by 0.12 mL/min/1.73 m2 (95% CI 0.01–0.23), principally associated with fruit-, vegetable- and nut-derived protein. The intake of animal protein was not associated with eGFR decline (P = 0.84).

      The researchers contended that “evidence suggests that the origin of protein may be an influential factor for kidney function.” According to Bernier-Jean and colleagues, this could be due to the fact that while plant-based proteins reduce acidosis, animal proteins contribute to the acid-load which may cause hyperfiltration and proteinuria.

      The results support the consumption of plant-sourced proteins the health benefits of plant-rich diets in the general population, particularly in older women to maintain kidney health.