Purpose of review: The present narrative review analyzes emerging research implicating vitamin D status and supplementation with skeletal muscle homeostasis and functions in two distinct segments of the adult population: young athletes and older adults.
Recent findings: Vitamin D deficiency compromises multiple indices of muscle function in young athletes and older adults. A variety of vitamin D3 (cholecalciferol) supplementation regimens may transition young athletes and older adults from deficient or inadequate to adequate vitamin D status. Vitamin D supplementation, used to treat a vitamin D deficiency, but not necessarily an inadequacy, promotes muscle anabolism in older adults. For both young athletes and older adults, vitamin D supplementation, which transitions them from inadequate to adequate vitamin D status, may not beneficially affect measures of muscle strength and power, or physical performance. Also, when vitamin D status is adequate, vitamin D supplementation to further increase serum 25(OH)D concentrations does not seem to confer additional benefits to muscle strength and power and physical performance.
Summary: The impacts of vitamin D status and supplementation on skeletal muscle homeostasis and functions seem comparable in young athletes who strive to maximize physical performance and older adults who seek to attenuate muscle mass and physical performance declines.