Double-blind, placebo-controlled pilot trial of L-Leucine-enriched amino-acid mixtures on body composition and physical performance in men and women aged 65–75 years

Abstract

Background/Objectives:Adequate protein intake is essential to retaining muscle and maintaining physical function, especially in the elderly, and L-Leucine has received attention as an essential amino acid (EAA) that enhances protein retention. The study's aim was to compare the efficacy of EAA mixtures on lean tissue mass (LTM) and functional performance (FP) in a healthy elderly population.Subjects/Methods:Thirty-six subjects (65–75 years) volunteered to receive capsules with EAAs (Groups A and B containing 20% and 40% L-Leucine, respectively) or placebo (lactose containing 0% L-Leucine, Group C) for 12 weeks. The daily amount ranged from 11 to 21 g (0.21 g/ kg/day) and was taken in two equal dosages alongside food, morning and evening. Main outcomes measured before and after intervention were LTM and FP (30-s arm-curl test; 30-s chair-stand test (30-CST); 6-min walk test (6-WT); and handgrip strength). Secondary outcomes included dietary intakes and physical activity.Results:Twenty-five subjects (11 male and 14 female) completed the study (Group A, n=8; Group B, n=8; Group C, n=9). Gains associated with medium effect sizes were noted in LTM (Group B, 1.1 ±1.1%, P=0.003) and FP (Group A in 30-CST (11.0±11.5%, P=0.02) and 6-WT (8.8±10.0%, P=0.02); Group B in 6-WT (5.8±6.6%, P=0.03) and a trend in 30-CST (13.2±16.0, P=0.06)). Significant differences between groups were not observed in secondary outcomes.Conclusions:Twice-daily supplementation of EAAs containing 20% or 40% L-Leucine improved aspects of functional status and at the higher level improved LTM. Further work to establish change in a larger sample and palatable supplemental format is now required.

The impact of dietary protein or amino acid supplementation on muscle mass and strength in elderly people: Individual participant data and meta-analysis of RCT's

“…We included a variable named 'study' to take into account differences between trials. One trial was coded 1a and 1b representing 20% leucine group vs. placebo group and 40% leucine group vs placebo group, respectively [21]. The pooled analyses were performed using SPSS Statistics (version 22) with statistical significance defined as p < 0.05.…”

Αcute effects of essential amino acid gel-based and whey protein supplements on appetite and energy intake in older women

“…It is generally agreed that protein-based oral nutritional supplements can be an effective means for improving functional capacity and body composition in older people (Dillon et al 2009;Ferrando et al 2010;Zhu et al 2011;Tieland et al 2012b;Bauer et al 2015;Cramer et al 2016;Ispoglou et al 2016). Nevertheless, there is limited evidence of their beneficial impact on muscle mass and strength of predominantly healthy older people (Tieland et al 2017).…”

“…Adapted from Ispoglou et al (2016) and Hulmi et al (2010). The GEL and WP were matched for total EAA content (~7.5 g each).…”

“…The key nutritional information per 100 g was: energy 967 kJ, fat 0.0 g, carbohydrate 44.7 g, protein 15 g, salt 0.2 g. The GEL and WP were matched by total EAA content with both supplements providing 7.5 g of EAA (Hulmi et al 2010;Ispoglou et al 2016), and therefore not energy-matched. In order to consume 7.5 g of EAA during the WP experimental trial, participants had to ingest 15.2 g of whey protein which was obtained through consumption of 21.2 g of the WP powder.…”

“…The corresponding macronutrient composition for each 50 ml GEL was 22 g, 7.5 g, and 0 g of carbohydrate, protein (all EAA), and fat respectively. The ratio of EAA in the GEL was the same as the 40% L-leucine formulation previously described by Ispoglou et al (2016). Please see Table 2 for essential amino acid profiling in the GEL and WP supplements.…”