The randomized clinical trial, conducted by researchers from the University of Texas Health Science Center, San Antonio, and published in Dietetics, focused on an understudied population: community-dwelling older adults with self-reported fatigue and reduced physical function.
Collected data indicated that, compared to placebo, the supplemented participants showed greater improvements in strength, mobility and endurance, along with reductions in fatigue and depressive symptoms.
One of the most notable findings was the improvement in chair stands in the supplemented group, which was nearly three times greater than that observed in the placebo group, suggesting enhanced muscular endurance and strength in participants receiving BCAAs.
“These functional gains are clinically meaningful, as reduced gait speed and poor 400 m walk performance are established predictors of falls, hospitalization, loss of independence and mortality in older adults,” the researchers noted.
Although the results are preliminary, with larger studies required to validate the findings, the study offers valuable insight into a prevalent and debilitating condition in older adults, with rates of fatigue ranging from 25% in primary care to as high as 98% in long-term care settings.
“Few studies have specifically targeted community-dwelling older adults with moderate fatigue or focused on mental fatigue outcomes, despite their relevance to quality of life and functional independence,” the researchers wrote.
“The inclusion of participants with elevated BMI and suboptimal functional status further enhances the clinical relevance, as these characteristics are prevalent among older adults at risk for physical decline.”
BCAAS in older adults
Branched-chain amino acids (BCAAs)—leucine, isoleucine, and valine—are essential amino acids that play a key role in muscle protein synthesis.
A standardized 2:1:1 leucine:isoleucine:valine ratio (as used in the current study) is commonly used in research and commercial products.
BCAAs are rapidly absorbed and may be better tolerated by older adults compared to whole protein or multi-nutrient supplements, allowing for targeted delivery of anabolic amino acids such as leucine.
Several studies have explored BCAA supplementation for its potential to enhance exercise performance, reduce muscle soreness and accelerate post-exercise recovery.
However, systematic reviews and meta-analyses have highlighted mixed findings, attributing inconsistencies to differences in study design, participant characteristics, dosing regimens and control for dietary protein intake.
The current study noted little is known about the combined effects of BCAA supplementation and exercise in older adults experiencing fatigue.
“This gap is especially important given the heightened vulnerability of older adults to both physical and mental fatigue, and their underrepresentation in clinical trials,” the researchers wrote.
Study details
The objective of this pilot, randomized, double-blind, placebo-controlled trial was to examine the impact of BCAA supplementation combined with exercise on physical and mental fatigue, physical performance and self-reported quality of life in fatigued older adults.
Both acute (single-dose) and longer-term (8-week) effects were assessed to provide preliminary evidence on feasibility, safety and potential efficacy.
Twenty participants (63% female; BMI: 35 ± 2 kg/m2; age: 70.5 ± 1.2 years) were randomized to 8 weeks of either exercise plus supplementation with BCAAs (100 mg/kg body weight/d) or exercise plus a placebo.
The program included moderate aerobic and resistance training three times weekly. Physical function was assessed using handgrip strength, chair stands, gait speed, VO2 max and a 400 m walk.
Psychological health was evaluated using the CES-D, Fatigue Assessment Scale (FAS), Insomnia Severity Index (ISI) and global pain, fatigue and quality of life using a visual analog scale (VAS).
Compared to placebo, the supplemented participants showed greater improvements in strength, mobility and endurance, along with reductions in fatigue (−45% vs. +92%) and depressive symptoms (−29% vs. +5%).
Time effects were also observed for ISI (−30%), FAS (−21%), and VAS quality of life (16%) following exercise + BCAA supplementation.
These preliminary results suggest that BCAAs combined with exercise may be an effective way to improve physical performance and reduce fatigue and depressive symptoms in older adults. Limitations included the small sample size and the pilot nature of the study which restricted the generalizability of the results.
The authors noted the potential for false positives increases with multiple comparisons, especially in a study of this scale.
Further, an imbalance in the sex distribution between the two groups may be a limitation, as differences in male and female physiology could influence the metabolic response to supplementation and confound the results.
The researchers noted that future studies should incorporate comprehensive dietary assessments to better control for and evaluate the potential influence of background diet on intervention outcomes.
Source: Dietetics. “Branched-Chain Amino Acids Combined with Exercise Improves Physical Function and Quality of Life in Older Adults: Results from a Pilot Randomized Controlled Trial”. doi: 10.3390/dietetics4030032 (registering dot). Authors: Ronna Robbins, et al.
