Vitamin D Does not Improve Muscle Strength

In view of all the hype surrounding vitamin D, I think it is my duty to report on "negative" or inconclusive results of the ongoing research of the effects what some call a vitamin, others a hormone. Stockton et al. (Stockton. 2010) have now published a systematic review of the effect of vitamin D on muscle strength. After evaluating data from 52 studies, involving 5,072 participants, their conclusion is quite unambiguous:

Based on studies included in this systematic review, vitamin D supplementation does not have a significant effect on muscle strength in adults with baseline 25(OH)D >25 nmol/L. However, a limited number of studies demonstrate an increase in proximal muscle strength in adults with vitamin D deficiency.

Bottom line: Go see a doctor, have your vitamin D levels checked and if you are deficient (if you are living in the Nothern Hemisphere, chances are that your levels are too low especially in the winter month), supplement with an adequate amount of vitamin D.