New research published in the Open Access journal Dietetics by researchers from the US shows that amino acid supplementation in combination with exercise could help improve physical performance, fatigue and mood in older adults.

The pilot clinical trial entailed the analysis of a group of older participants, both male and female over a period of 8 weeks. Here, the participants carried out various exercises and were given an amino acid supplement or placebo and were then assessed after eight weeks.

The research suggests potential new, non-pharmacological interventions to treat fatigue and improve quality of life in older adults.

Exercise and fatigue

Exercise is a critical aspect of keeping well across all ages. Evidence shows that it provides significant physical and mental health benefits and is a modifiable lifestyle factor to reduce the risk of developing many diseases. This includes various cancers and metabolic and cardiovascular diseases.

Sedentary lifestyles can reduce the amount of physical activity an individual does in a day and may result in various health problems. This could include tiredness and fatigue, especially in older adults. Fatigue can manifest as both physical and cognitive symptoms such as feelings of exhaustion, muscle weakness, low mood and anxiety. Exercise, alongside maintaining a healthy diet and getting enough sleep, is important to reduce the risk of fatigue.

Supplementation of branched amino acids (BCAAs) (leucine, isoleucine and valine) is used by individuals to support muscle recovery and reduce fatigue induced by exercise.

The role of amino acids in helping fatigue

Muscle protein synthesis is the process of building muscle after exercise. These processes enable the muscle to adapt to exercise and trigger muscle remodelling and turnover.

Being protein ‘building blocks’, amino acids play a critical role in muscle protein synthesis. Therefore, diet and nutrition are essential to muscle recovery. BCAAs are commercially available amino acids that are quickly absorbed by the body and have been used in research to understand the role of amino acids in muscle recovery after exercise.

However, previous studies have shown conflicting results, with some showing a lack of significant effects from taking BCAA for muscle recovery.

Amino acids may also play a role in inflammation in older adults, who are likely to experience higher levels of inflammation and inflammatory disease. This is termed ‘age-related inflammatory disease’ and includes diseases like cancer, cardiovascular disease and musculoskeletal conditions like arthritis and osteoporosis.

“We’ve been studying for years how inflammation contributes to functional decline with normal aging or during disease,” said Jason O’Connor, PhD, associate professor and author of the study. He continues: “Among the many factors implicated in this process, the metabolism of amino acids appears to play an important role.”

Therefore, the research carried out here aimed to demonstrate how BCAA supplementation combined with exercise could help physical performance, muscle recovery, and fatigue in older adults.

Study design

The study consisted of a randomized, double-blind placebo-controlled trial of twenty participants split into two groups: an exercise + BCAA group and an exercise + placebo group as a control. The participants were from a diverse range of ethnic backgrounds, including non-Hispanic white, Hispanic white and non-Hispanic black individuals. The majority of the participants were classified as obese, with 16% having sarcopenia (skeletal muscle loss).

The assessment of psychological factors was provided by participants self-reporting the status of their mental fatigue and psychological health. This included a measure of depressive symptoms, insomnia severity, perceived quality of life, and fatigue. The assessment of physical performance included a walking and handgrip test, a lower extremity chair test, and a cardiopulmonary test.

BCAA and exercise improves symptoms of fatigue in older adults

The results showed that BCAA and exercise had profound benefits on physical and mental health in older adults. It was demonstrated that exercise + BCAA supplementation exhibited a 45% reduction in fatigue and 29% reduction in depressive symptoms. In contrast, exercise alone showed insignificant effects on physical performance and accompanied a 5% increase in fatigue.

“In our evidence and from the literature, these amino acids do more than just serve as building blocks for protein. They have direct effects. Leucine has an effect on skeletal muscle and interplays with other amino acids transported into the brain that potentially have an effect on mental fatigue.” – Jason O’Connor.

Therefore, the results confirm that BCAA supplementation can boost exercise performance and mood in older adults. It also suggests that amino acid metabolism may have direct links to the mechanisms involved in inflammation, prompting further study.

“There is a general notion that getting older also entails having more inflammation. In follow-up studies, we plan to analyze biological parameters to see if there is a relationship between the functional changes that we saw with physical performance and mental health measures and changes in the immune system.” – Jason O’Connor.

Future research would entail understanding how BCAA is involved in boosting physical performance and mood by elucidating the mechanism of action of amino acids in mediating these factors in older adults.

To read more, access the journal Dietetics, or the full MDPI Journal list, where all articles are free to access and read immediately.