Effects of Branched-Chain Amino Acids on Skeletal Muscle, Glycemic Control, and Neuropsychological Performance in Elderly Persons with Type 2 Diabetes Mellitus: An Exploratory Randomized Controlled Trial

Abstract

Although branched-chain amino acids (BCAA) are known to stimulate myofibrillar protein synthesis and affect insulin signaling and kynurenine metabolism (the latter being a metabolite of tryptophan associated with depression and dementia), the effects of BCAA supplementation on type 2 diabetes (T2D) are not clear. Therefore, a 24-week, prospective randomized open blinded-endpoint trial was conducted to evaluate the effects of supplementation of 8 g of BCAA or 7.5 g of soy protein on skeletal muscle and glycemic control as well as adverse events in elderly individuals with T2D. Thirty-six participants were randomly assigned to the BCAA group (n = 21) and the soy protein group (n = 15). Skeletal muscle mass and HbA1c, which were primary endpoints, did not change over time or differ between groups. However, knee extension muscle strength was significantly increased in the soy protein group and showed a tendency to increase in the BCAA group. Homeostasis model assessment for insulin resistance did not significantly change during the trial. Depressive symptoms were significantly improved in the BCAA group but the difference between groups was not significant. Results suggested that BCAA supplementation may not affect skeletal muscle mass and glycemic control and may improve depressive symptoms in elderly individuals with T2D.

Effects of Plant-Based Protein Interventions, with and without an Exercise Component, on Body Composition, Strength and Physical Function in Older Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

“…The included study characteristics are reported in Table 3 . The studies were conducted in United States ( n = 3, [ 47 , 48 , 49 ]), Japan ( n = 3, [ 50 , 51 , 52 ]), Iran ( n = 2, [ 53 , 54 ]), Netherlands ( n = 1, [ 46 ]), China ( n = 1, [ 55 ]), and Brazil ( n = 1, [ 56 ]). In total, there were 806 participants included from studies published between 2002–2022.…”

“…The overall daily dose of protein varied from 0.6 g to 60 g. Most studies provided protein supplementation daily, except for Imaoka et al [ 50 , 51 ] which provided one 4.4 g dose of soy peptide drink once per week. Six studies included an exercise component of either resistance training (RT), aerobic training or both [ 47 , 50 , 51 , 52 , 54 , 56 ]. Bijeh et al [ 54 ] was the only study to include a soy only arm, and a soy + RT arm, which could be compared separately to a control (no intervention) and RT only arm, respectively.…”

“…Bijeh et al [ 54 ] was the only study to include a soy only arm, and a soy + RT arm, which could be compared separately to a control (no intervention) and RT only arm, respectively. Comparisons included animal protein [ 46 , 47 , 48 , 49 , 52 , 54 , 55 , 56 ], no intervention control [ 53 , 55 ], and exercise only controls [ 50 , 51 , 54 , 56 ]. Bakhtiari et al [ 53 ] provided two soy arms (soy nut or textured soy protein) compared to no intervention control, while Beavers et al [ 49 ] was a dedicated weight loss study with both plant-protein and animal-protein (control) interventions in a planned calorie deficit.…”

“…The narrative summaries of plant protein interventions on outcomes of body composition, strength, and physical function are described in Table 4 . Many studies reported an overall positive effect of the soy interventions over time, with no significant differences between groups reported with comparison interventions of animal protein, exercise only, exercise + animal protein, or no intervention [ 47 , 49 , 50 , 51 , 52 , 53 , 55 , 56 ]. The benefits of plant based protein interventions were strongest for lean muscle mass maintenance and accrual as measured by DEXA or BIA [ 50 , 51 , 53 , 55 , 56 ], with no effect seen in any intervention group for bone mineral density (DEXA) [ 46 , 48 ].…”

Fermented Whey Protein Supplementation Improves Muscular Strength, Muscle Parameters, and Physical Performance in Middle-Aged Korean Adults: An 8-Week Double Blind Randomized Controlled Trial

“…Non-fermented whey protein supplementation was tested on muscle hypertrophy in various resistance training studies, where findings indicated that specific peptides may provide muscle recovery capabilities, while their antioxidant capacities may also contribute towards recovery physiological responses to exercise ( Devries and Phillips, 2015 ; Ha and Zemel, 2003 ; Stark et al, 2012 ). There have been several studies on the improvement of muscle parameters with whey protein supplementation ( Andersen et al, 2005 ), fermented whey proteins (FWP) on protein digestion and absorption, increment of branched chain amino acids levels, and effects of fermentation on calcium absorption and bone density improvement ( Matsuda et al, 2022 ). However, the effects of fermented whey supplementation on muscle strength and physical performance have not been investigated.…”