An adequate vitamin D supply may improve muscle strength

According to a new review from the UK, vitamin D supplementation can increase upper and lower limb strength.

The review and meta-analysis combined the results of six randomized controlled trials with a total of
310 healthy adults 18-40 years old, which investigated a potential effect of vitamin D supplementation on upper and lower limb muscle strength (1). The analysis showed that increased intakes of vitamin D (4000 IU per day to 60,000 IU per week) for 4 weeks to 6 months significantly increased muscle strength of the participants compared to placebo.

The researchers commented that further research should focus on the effect of vitamin D on muscle power, endurance and maximal strength. Vitamin D receptors have been identified in muscle cells which supports the concept of a direct effect of the vitamin on muscle tissue. An earlier review concluded that vitamin D supplementation does not seem to have a significant effect on muscle strength in adults with baseline blood concentrations higher than 25 nmol/L (2). However, an increase in upper and lower limb strength seems to be achieved in adults with vitamin D deficiency.

1. Tomlinson P. B. et al. 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. Published online August 2014.
2. Stockton K. A. et al. Effect of vitamin D supplementation on muscle strength: a systematic review and meta-analysis. Osteoporosis International. 2011; 22(3):859-871.