The Recommended Daily Allowance (RDA) for protein intake in the adult population is widely promoted as 0.8 grams/kg/day. Aging may increase protein requirements, particularly to maintain muscle mass.
Authors investigated whether controlled protein consumption at the current RDA or twice the RDA (2 x RDA) affects skeletal muscle mass and physical function in elderly men.
Study found that consumption of a diet providing 2 x RDA for protein compared with the current guidelines was found to have beneficial effects on lean body mass and leg power in elderly men.
AJCN
Also see:
Protein intake in aging adults
Aging, Diabetes and Cardiovascular Illness
Frailty and exercise in aging population
AM J CLINICAL NUTRITION
Randomized
November 2017
Background:
The Recommended Daily Allowance (RDA) for protein intake in the adult population is widely promoted as 0.8 grams/kg/day. Aging may increase protein requirements, particularly to maintain muscle mass.
Objective:
We investigated whether controlled protein consumption at the current RDA or twice the RDA (2RDA) affects skeletal muscle mass and physical function in elderly men.
Design:
In this parallel-group randomized trial, 29 men aged >70 years (mean BMI 28) were provided with a complete diet containing either 0.8 (RDA) or 1.6 (2 x RDA) grams protein/kg/day, aimed to balance energy needs. Before treatment and after 10 wk of intervention, whole-body and appendicular lean mass were measured by using dual-energy X-ray absorptiometry. Knee-extension peak power was measured with dynamometry.
Results:
Both groups were found to have been in a moderate negative energy balance. In comparison with RDA, whole-body lean mass increased in 2RDA (P = 0.001; 1.49 ± 1.30 kg). This difference was mostly accounted for by an increase in trunk lean mass found in 2RDA (+1.39 ± 1.09 kg, P < 0.001). Appendicular lean mass also decreased in RDA compared with 2RDA ( P = 0.022), driven by a reduction in RDA. Adjusting for energy imbalances did not alter these findings. Knee-extension peak power was also differently affected.
Conclusions:
Consumption of a diet providing 2 x RDA for protein compared with the current guidelines was found to have beneficial effects on lean body mass and leg power in elderly men. These effects were not explained by differences in energy balance.