Sarcopenia – the atrophy of skeletal muscle – is becoming a larger problem with the elderly population, leading to functional decline, and is associated with increased falls and immobility, acute and chronic illnesses, fatigue, and mortality. It often is a measurement of the health and well-being of the older population. Muscle mass and strength naturally begin to decline around the 4th decade of life unless sustained by exercise, and nearly 50 percent of one’s muscle mass can be lost by the 8th decade of life. Both size and number of type 2 fast-twitch muscle cells decline and they are replaced with rising amounts of fibrous and adipose tissue.
Skeletal muscle makes up over half the entire body’s mass and is metabolically active tissue, meaning a great loss of this tissue can have profound consequences on metabolic health, including insulin resistance. Sarcopenia is found in 12 to 60 percent of chronic illnesses and 15 to 90 percent of endocrine disorders. The association is not exclusively causative, but a strong interplay between muscle mass and health cannot be ignored and suggests that an improvement in muscle mass can lead to better health.
Muscle fibers alone aren’t the only cause of sarcopenia. More recent research is pointing to altered mitochondrial biogenesis and function as an additional consideration in the health outcomes associated with sarcopenia, which partially explains the wide variety of clinical outcomes associated with loss of muscle mass.
A recent study, published in 2017 in the Journals of Gerontology, suggests that resveratrol may be useful in enhancing both cellular and functional changes common in sarcopenia to improve health outcomes. Previous in vitro studies showed that resveratrol could possibly increase muscle protein synthesis while subsequently decreasing muscle degradation and therefore, slow the process of muscle atrophy. Similarly, in vivo rat studies showed that resveratrol halted the loss of muscle fibers. Therefore, a study of 30 healthy, older adults aged 65 to 80 years were randomly given either 500mg per day of resveratrol or a placebo for 12 weeks, while also completing both aerobic and resistance exercise. The study results confirmed that the resveratrol treatment improved mitochondrial density, delayed muscle fatigue, and increased muscle strength. The placebo group showed that exercise alone could not induce the same degree of metabolic changes that are important in sarcopenia-induced health consequences.
Resveratrol, a bioactive polyphenol richly sourced in red wine and Japanese knotweed (Polygonum cuspidatum), is known to improve mitochondrial function under in vitro and in vivo conditions and promote mitochondrial biogenesis. This powerful polyphenol not only increases the aerobic capacity (which can aid in exercise and therefore, indirectly, improve exercise-induced muscle mass and strength) but it also induces genes required for oxidative phosphorylation and mitochondrial biogenesis. The impact of resveratrol on mitochondrial function is one of the primary means by which it has earned its reputation as an anti-aging nutraceutical. Mitochondrial function naturally declines with age, leading to increased oxidative stress and signs of aging. But as research indicates, aging is more than skin deep. The effects of reduced mitochondria function even reach deep within the skeletal muscles, reducing the metabolic activity within, which inevitably leads to reduced function and sarcopenia.
Age-related changes in the angiotensin system are also responsible for muscle loss in the elderly. When functioning adequately, this system will help support muscle healing during exercise and prevent muscle atrophy. Angiotensin receptors are found within the mitochondria, but their numbers also decline with age. Therefore, as resveratrol targets mitochondria, supporting the production and function of these organelles, it indirectly improves the efficiency of the angiotensin system, which can further support the maintenance and function of skeletal muscle in the elderly.
Sarcopenia is far more than that the loss of muscle fibers; it also arises from inadequate mitochondria function and a waning angiotensin system. While exercise is certainly a preliminary requirement for preventing sarcopenia, resveratrol can enhance the growth of muscle fibers by addressing the metabolic changes that contribute to sarcopenia and prevent the rapid development of the various health challenges associated with it.