Effects of vegetarian versus Mediterranean diet on kidney function: Findings from the CARDIVEG study

BACKGROUND: The aim of the present study was to assess the effects of a lacto‐ovo‐vegetarian diet (VD), compared to a Mediterranean diet (MD), on kidney function in a group of subjects with medium‐to‐low cardiovascular risk profile. METHODS: We analysed 107 subjects (82 women, 25 men; median age 52) who followed a VD (n = 54) and a MD (n = 53) for 3 months in the CARDIVEG study, a randomized, open, crossover trial that compared the effects of these 2 diets on cardiovascular disease risk. RESULTS: The effect of the two diets on kidney function markers was evaluated by conducting a general linear model for repeated measurements adjusted for possible confounding factors such as age, sex, physical activity, alcohol, smoking, hypertension, LDL cholesterol, glucose and body weight change. A significant reduction in creatinine (−5.3%; P < .001), urea nitrogen levels (−9%; P = .001), blood urea nitrogen (BUN) (−8.7%; P = .001) and BUN/creatinine ratio (−5.8%; P < .001), and an increase in estimated glomerular filtration rate (eGFR) (+3.5%; P = .001) was observed during the VD period. On the contrary, no significant changes were noted in the MD group. Variations obtained in the two dietary interventions were significantly different (P < .0001) for creatinine levels, BUN/creatinine and eGFR, for which opposite trends were observed in the VD and MD groups. CONCLUSIONS: In a selected group of subjects with medium‐to‐low cardiovascular risk profile, a 3 month VD period determined significant improvements in kidney function markers. Further trials are needed to confirm these results.