Preventive Effects of Medium-Chain Fatty Acid Intake on Muscle Atrophy.

: Medium-chain fatty acids (MCFAs), abundant in coconut oil, have attracted considerable attention in recent years owing to their potential impact on muscle atrophy. However, the mechanisms underlying their effects remain inadequately understood. This study aimed to examine the impact of coconut-oil-derived MCFAs on skeletal muscle in a mouse model administered a high-fat diet. C57BL/6J mice were assigned to a normal diet, lard diet, or coconut oil diet and maintained for a duration of 12 weeks. A glucose tolerance test was conducted, and biochemical parameters, muscle histological analysis, and gene expression in muscle tissue were assessed. MCFA concentrations in serum and muscle were quantified utilizing gas chromatography-mass spectrometry. An in vitro experiment was conducted by treating mouse C2C12 myotube cells with lauric acid and palmitic acid, followed by a gene expression evaluation. Mice fed a coconut-oil-based diet exhibited reduced body weight gain and lower blood glucose and total cholesterol levels compared to those fed a lard-based diet. The coconut-oil-fed group showed increased concentrations of MCFAs in both serum and muscle tissue, along with an improvement in relative grip strength. The expression levels of proteins and genes associated with muscle atrophy were reduced in muscle tissue. These findings were corroborated in vitro using C2C12 myotube cells. Coconut oil may preserve muscle strength by increasing MCFA concentrations in serum and muscle tissue, while suppressing the expression of muscle-atrophy-related proteins and genes. These findings suggest that coconut oil may be beneficial in preventing muscle atrophy induced by long-chain fatty acids.