Studies on Skeletal Muscle Health and Functional Food Components

(JSNFS Award for Excellence in Research (2024))

Abstract

Any decrease in the quantity or quality of skeletal muscle leads to a decrease in physical activity. Physical inactivity not only increases the risk of developing metabolic diseases such as obesity and type 2 diabetes, but also leads to a bedridden state in the elderly. Skeletal muscle health is regulated by food components that are ingested daily. Therefore, we have been conducting research to clarify the molecular mechanisms by which food components exert beneficial effects on skeletal muscle health. Here, we summarize the results obtained for three food components: (1) The isoflavone daidzein increased skeletal muscle mass by suppressing the expression of the deubiquitinase USP19 via estrogen receptor β in female mice, but not male mice; (2) Provitamin A, i.e., β-carotene and β-cryptoxanthin, suppressed soleus muscle atrophy in bedridden and aged model mice, respectively. Furthermore, transglutaminase 2, which was identified as a vitamin A-responsive gene, was involved in the β-carotene-induced increase in soleus muscle mass as a secreted protein; and (3) The fatty acid amide oleamide suppressed atrophy of the tibialis anterior muscle in mice housed in small cages to enforce sedentary behavior.