Chang Woock Lee

Cholesterol and Skeletal Muscle Health

In the United States, more than 400,000 people die every year directly due to physical inactivity and poor nutrition [1]. This accounts for 1/3 of all preventable deaths and 1/6 of all deaths. Increasingly, skeletal muscle has been identified as playing a central role in the modifiable risk associated with modern chronic disease with physical activity/muscle contraction being the central control point. The common link between more than 20 diseases and conditions affected by physical inactivity [2] is skeletal muscle. Skeletal muscle comprises 40–50% of the body mass, more than 50% of overall metabolism and only skeletal muscle activity can increase whole body metabolism 10-fold or greater, making the impact of caloric, fat and cholesterol intake on disease dependent, or at least interactive, with muscle activity. Skeletal muscle is the site of the largest glucose disposal, becomes insulin resistant with inactivity and skeletal muscle dysfunction, and correction of the dysfunction is the best predictor of diabetes outcomes. Skeletal muscle use and proper function contribute to cardiovascular health partly through accelerated metabolism, weight control, increased vascularization, cholesterol regulation, anti-inflammatory effects and pro-vasodilatory control. Skeletal muscle contraction directly stimulates growth or maintenance to prevent or treat the debilitating loss of muscle (sarcopenia) and bone (osteoporosis) associated with aging. Although it appears not to be widely known, it has been reported that 1/3 of cancer deaths are due to cachexia, disease-associated muscle loss, and not the cancer itself, perhaps due to the many downstream effects of inactivity, skeletal muscle’s role as a systemic amino acid buffer or due to the underlying mechanism (currently unknown) for the strong link between muscle activity and several cancers. Thus, optimal skeletal muscle function would appear to have a substantial impact on modern chronic diseases.