The effects of dietary protein intake on appendicular lean mass and muscle function in elderly men: a 10-wk randomized controlled trial

Abstract

, 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 (mean 6 SD RDA: 209 6 213 kcal/d; 2RDA 145 6 214 kcal/d; P = 0.427 for difference between the groups). In comparison with RDA, whole-body lean mass increased in 2RDA (P = 0.001; 1.49 6 1.30 kg, P , 0.001 compared with 20.55 6 1.49 kg, P = 0.149). This difference was mostly accounted for by an increase in trunk lean mass found in 2RDA (+1.39 6 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 (20.64 6 0.91 kg, P = 0.005 compared with 0.11 6 0.57 kg, P = 0.592). Adjusting for energy imbalances did not alter these findings. Knee-extension peak power was also differently affected (P = 0.012; 26.6 6 47.7 W, P = 0.015 in 2RDA compared with 211.7 6 31.0 W, P = 0.180 in RDA). Conclusions: Consumption of a diet providing 2RDA 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. This trial was registered at the Australia New Zealand Clinical Trial Registry (www.anzctr.org.au) as ACTRN12616000310460.Am J Clin Nutr 2017;106:1375-83.

Protein supplementation improves lean body mass in physically active older adults: a randomized placebo‐controlled trial

“…Therefore, SPPB may not be an adequate test in this active group to assess the effect of additional protein supplementation . In parallel, the TUG test reports in community‐dwelling older adults average scores between 7.9 and 9.0 s, whereas our participants already scored 6.9 ± 0.9 s at baseline, thus creating a small window for improvement. Therefore, we should be cautious with our findings that protein supplementation had no effect on physical performance because our tests used may not have been suitable for such an active population.…”

Comprehensive Profiling of the Circulatory miRNAome Response to a High Protein Diet in Elderly Men: A Potential Role in Inflammatory Response Modulation

“…The population involved in this study has been previously described in relation to the effects of dietary protein on physical function and body composition . Overall thirty‐one healthy men ≥70 years were recruited ( Table ).…”

“…Given the importance of dietary proteins, international population health guidelines propose a minimum recommended dietary allowance of 0.8 g kg –1 day –1 (RDA) for protein for all adults over 18 years irrespective of sex or age based on measurements of nitrogen balance . However, in the elderly, this level of protein intake is likely insufficient to maintain skeletal muscle mass and physical function . It has been proposed that a protein intake between 1.0 and 2.0 g kg –1 day –1 may be required to promote optimal health in older adults .…”

“…In the elderly, reduced energy needs along with appetite loss increase the risk of insufficient protein intake . This inadequate protein intake in the presence of anabolic resistance accelerates the loss of skeletal muscle mass and blunts muscle protein synthesis, predisposing the elderly to greater risk of functional impairment, mortality, and reduced quality of life . Moreover, increasing the intake of dietary protein is reported to improve glycaemic control and insulin sensitivity in elderly diabetics .…”

“…The current study comprehensively characterized the expression of the circulatory miRNAome in response to altered dietary protein, using an untargeted and unbiased approach of high‐throughput small RNA sequencing (HTS) . The study was conducted in a cohort of healthy men (≥70 years), fed a diet containing either RDA (0.8 g kg –1 day –1 ) or twice the RDA (2RDA, 1.6 g kg –1 day –1 ) of protein for 10 weeks . The aims were then to quantify the expression of circulatory miRNAs, with the goal of identifying the possible functional impact of any measured alteration.…”