Prevention of Loss of Muscle Mass and Function in Older Adults during COVID-19 Lockdown: Potential Role of Dietary Essential Amino Acids

As the COVID-19 pandemic became a global emergency, social distancing, quarantine, and limitations in outdoor activities have resulted in an environment of enforced physical inactivity (EPI). A prolonged period of EPI in older individuals accelerates the deterioration of skeletal muscle health, including loss of muscle mass and function, commonly referred to as sarcopenia. Sarcopenia is associated with an increased likelihood of the progression of diabetes, obesity, and/or depression. Well-known approaches to mitigate the symptoms of sarcopenia include participation in resistance exercise training and/or intake of balanced essential amino acids (EAAs) and high-quality (i.e., containing high EEAs) protein. As the pandemic situation discourages physical exercise, nutritional approaches, especially dietary EAA intake, could be a good alternative for counteracting against EPI-promoted loss of muscle mass and function. Therefore, in the present review, we cover (1) the impact of EPI-induced muscle loss and function on health, (2) the therapeutic potential of dietary EAAs for muscle health (e.g., muscle mass and function) in the EPI condition in comparison with protein sources, and finally (3) practical guidelines of dietary EAA intake for optimal anabolic response in EPI.