Limited evidence. Direction: No effect.
C Limited
Rubric condition met: Meta-analyses disagree (small positive SMD 0.17 in 30 RCTs versus no benefit and possible harm in 54 placebo-controlled RCTs; null overall in 8 RCTs in athletes): C with direction none
A 2014 meta-analysis of 30 RCTs (mean age 61.1) found a small positive effect on global muscle strength (SMD 0.17), larger in people with low 25-hydroxyvitamin D and those aged 65 or older, and no effect on muscle mass or power. A 2021 meta-analysis of 54 placebo-controlled RCTs (8,747 people) found no benefit, slightly slower timed up-and-go and lower knee flexion strength with vitamin D, and no difference in low-vitamin D subgroups. In athletes, 8 RCTs found no overall effect. A 2011 meta-analysis found no effect in adults with 25(OH)D above 25 nmol/L, and a large effect on hip strength in two studies of deficient participants. Evidence is mixed, so the proposal is C with direction none.
| Study | Year | Design | Participants | Result |
|---|---|---|---|---|
| Stockton 2011 | 2011 | meta-analysis | 5072 | result not recorded |
| Beaudart 2014 | 2014 | meta-analysis | 5615 | result not recorded |
| Zhang 2019 | 2019 | meta-analysis | 284 | result not recorded |
| Bislev 2021 | 2021 | meta-analysis | 8747 | result not recorded |
Zhang L, Quan M, Cao ZB. Effect of vitamin D supplementation on upper and lower limb muscle strength and muscle power in athletes: A meta-analysis PLoS One, 2019. PMID 31039170
Stockton KA, Mengersen K, Paratz JD. Effect of vitamin D supplementation on muscle strength: a systematic review and meta-analysis Osteoporos Int, 2011. PMID 20924748
Bislev LS, Grove-Laugesen D, Rejnmark L. Vitamin D and Muscle Health: A Systematic Review and Meta-analysis of Randomized Placebo-Controlled Trials J Bone Miner Res, 2021. PMID 34405916
Beaudart C, Buckinx F, Rabenda V. The effects of vitamin D on skeletal muscle strength, muscle mass, and muscle power: a systematic review and meta-analysis of randomized controlled trials J Clin Endocrinol Metab, 2014. PMID 25033068
Search (): vitamin d[ti] AND (muscle strength[tiab] OR strength[ti]) AND (meta-analysis[pt] OR systematic review[pt])
