1. Introduction
loss of skeletal muscle mass, sarcopenia, decreased appetite, Frailty, weight loss
LOSS OF SKELETAL MUSCLE MASS, CLINICAL SYNDROME, SARCOPENIA, UNDERNUTRITION
An adequate nutritional intake is recommended for the prevention of physical frailty and sarcopenia. In particular, medium-chain fatty acids (MCFAs) are reportedly important for muscle strength in nursing home residents. However, the effects of MCFAs on healthy adults at risk for frailty remain unknown. Hence, a randomized, placebo-controlled study was conducted to investigate the effects of 12 weeks of medium-chain triglycerides (MCTs) intake and walking on muscle mass and function in healthy, sedentary, middle-aged and older adults with a low body mass index. Three MCT intake groups with different amounts of octanoic and decanoic acid intake were compared with a control group. After 12 weeks, knee extension strength increased in all groups, with the increases in all MCT intake groups being significantly higher than those in the control group (Frailty, which can occur when elderly persons experience a decline in physical and mental health, is associated with a higher risk of hospitalization and mortality [Fried et al. defined frailty as a clinical syndrome in which three or more of the following criteria are present: unintentional weight loss (10 lbs in past year), self-reported exhaustion, weakness (grip strength), slow walking speed, and low physical activity. Xue et al. further associated physical frailty with decreased intake (decreased appetite) and sarcopenia, identifying chronic undernutrition (inadequate intake of protein and energy) as a cause of weight loss, and sarcopenia as a cause of exhaustion, low physical activity, slow walking speed, and weakness (e.g., reduced grip strength) [Several reports have observed an association between nutritional status and frailty, with cross-sectional studies showing an association between low energy intake and frailty and an increased risk of frailty with low energy intake [Medium-chain fatty acids (MCFAs) are straight-chain saturated fatty acids with carbon numbers between 6 and 12 in length. Medium-chain triglycerides (MCTs), which are composed of MCFAs, are oils that are preferentially converted into energy in the body after ingestion, unlike long-chain fatty acids (LCFAs) that are found in regular oils [In this study, we tested whether continuous MCT intake is effective in maintaining and preventing loss of skeletal muscle mass and strength in healthy community-dwelling middle-aged and older adults. Along with continuous MCT intake, subjects engaged in moderate-intensity walking, and the impact of different MCT amounts and MCFAs compositions was examined. A combination of walking (an aerobic exercise that is easier to perform than resistance training) and MCT intake can maintain or suppress the reduction in skeletal muscle mass and strength in middle-aged and older adults at risk of frailty. Moreover, foods containing MCFAs as well as an active lifestyle may help middle-aged and older adults maintain their health.