Dietary supplementation of Vitamin D may enhance muscle strength, among young healthy adults.
Vitamin D is most widely recognized to exert bone and immune effects. PB Tomlinson, from the University of London (United Kingdom), and colleagues completed a meta analysis of published studies of vitamin D and muscle strength in healthy adults (ages 18 to 40 years), covering a total of 310 subjects. Selected trials lasted from 4 weeks to 6 months and dosages differed from 4000IU per day to 60,000IU per week. Upper and lower limb muscle strength both showed a standardized mean difference of 0.32, for which h the investigators “[suggest] vitamin D supplementation significantly increased muscle strength.”
Tomlinson PB, Joseph C, Angioi M. “Effects of vitamin D supplementation on upper and lower body muscle strength levels in healthy individuals. A systematic review with meta-analysis.” J Sci Med Sport. 2015 Sep;18(5):575-80.