Potential roles of vitamin E in age-related changes in skeletal muscle health

E. Chung, H. Mo, S. Wang, Y. Zu, M. Elfakhani, S.R. Rios, M.C. Chyu, R.S. Yang, C.L. Shen

Nutr Res. 2018;49:23-36

Skeletal muscle disorders including sarcopenia are prevalent during the complex biological process of aging. Loss of muscle mass and strength commonly seen in sarcopenia is induced by impaired neuromuscular innervation, transition of skeletal muscle fiber type, and reduced muscle regenerative capacity, all attributable to chronic inflammation, oxidative stress, and mitochondrial dysfunction.

Current literature suggests that vitamin E molecules (α-, β-, γ-, δ-tocopherols and the corresponding tocotrienols) with their antioxidant and anti-inflammatory capabilities may mitigate age-associated skeletal dysfunction and enhance muscle regeneration, thus attenuating sarcopenia. Preclinical and human experimental studies show that vitamin E benefits myoblast proliferation, differentiation, survival, membrane repair, mitochondrial efficiency, muscle mass, muscle contractile properties, and exercise capacity.

Limited number of human cross-sectional observational studies reveal positive associations between serum tocopherol level and muscle strength. Several factors, including difficulties in validating vitamin E intake and deficiency, variations in muscle-protective activity and metabolism of diverse forms of vitamin E, and lack of understanding of the mechanisms of action, preclude randomized clinical trials of vitamin E in people with sarcopenia.

Future research should consider long term clinical trials of with adequate sample size, advanced imaging technology and omics approaches to investigate underlying mechanisms and assess clinically meaningful parameterssuchasmusclestrength,physicalperformance,andmusclemassinsarcopenia prevention and/or treatment.

Comment: A typical human diet is likely to provide sufficient tocopherols, but not tocotrienols. Due to the scarcity of tocotrienols in typical diet, the doses of tocotrienols used in the clinical studies may likely be achieved only with supplements. For an adult, vitamin E (α-tocopherol) RDA is 15 mg or 22.4 IU. Consistent with the finding from the National Health and Nutrition Examination Survey (NHANES), that most people in U.S. consume less than the RDA level of vitamin E, several studies showed the high prevalence of vitamin E deficiency in the free-living American elderly population potentially contributing to skeletal myopathy and frailty due to loss of muscle strength