Glomerular filtration rate after a 12-wk resistance exercise program with post-exercise protein ingestion in community dwelling elderly.

OBJECTIVE: Increased protein intake and resistance exercise can be beneficial for maintenance of lean body mass (LBM) in older adults. However, these factors could also negatively affect renal function. We investigated changes in renal function after a 12-wk resistance exercise program combined with protein supplementation in community dwelling older adults.

METHODS: Patients (N = 237, 73.7 ± 5.7 y, 58.2% female) participated in a 12-wk resistance exercise program (3 times/wk) designed to increase strength and muscle mass of major muscle groups. Participants were randomly assigned to one of three dietary supplements consumed directly after training: whey protein drink (20 g whey protein, 20 g carbohydrates), milk protein drink (20 g milk protein, 20 g carbohydrates), or carbohydrate drink (40 g carbohydrates). Renal function was estimated as glomerular filtration rate (GFR, Cockcroft-Gault formula), and dietary intake was measured as 3-d-weighed food record at baseline and endpoint.

RESULTS: During the intervention, energy intake did not increase. Carbohydrate intake increased in the carbohydrate group and protein intake increased in the milk group, both approximately in accordance with the supplementation. In the whey group, protein intake did not increase, but carbohydrate intake did. GFR increased after the intervention (+4.4 mL/min/1.73 m2; P < 0.001), and the changes were similar in men and women or in the age quartiles. Changes in GFR at endpoint were not associated with LBM, dietary supplements, or total protein intake.

CONCLUSIONS: A 12-wk resistance exercise program combined with protein supplementation in community dwelling older adults does not negatively affect GFR. The supplementation had only minor effects on total dietary intake.