Vitamin D Supplementation and Muscle Strength: A Meta-Analysis
Stockton KA, Mengersen K, Paratz JD, Kandiah D, Bennell KL
Published in Osteoporosis International
Abstract
Meta-analysis showing vitamin D supplementation significantly improves muscle strength, particularly in individuals with deficiency.
Methodology
Systematic review and meta-analysis of randomised controlled trials of vitamin D supplementation reporting muscle strength outcomes (grip strength, proximal lower limb strength), with subgroup analysis by baseline 25(OH)D.
Key Findings
In participants with baseline serum 25(OH)D above 25 nmol/L, vitamin D supplementation produced no significant improvement in grip strength or proximal lower limb strength. In the subgroup with baseline 25(OH)D below 25 nmol/L, supplementation significantly increased hip muscle strength (standardised mean difference 3.52).
Conclusions
Vitamin D improves muscle strength only in people who are genuinely deficient. Supplementing people with adequate vitamin D status does not measurably increase strength.
Limitations
Marked heterogeneity in dose, form (D2 vs D3), duration and strength testing protocols; the deficient subgroup was small, so the large effect estimate is imprecise; several trials had unclear allocation concealment.
Supplements Studied
In participants with baseline serum 25(OH)D above 25 nmol/L, vitamin D supplementation produced no significant improvement in grip strength or proximal lower limb strength. In the subgroup with baseline 25(OH)D below 25 nmol/L, supplementation significantly increased hip muscle strength (standardised mean difference 3.52).
Outcomes Measured
Meta-analysis shows vitamin D supplementation significantly improves muscle strength, particularly in individuals with baseline deficiency. Effects are most pronounced in older adults.
Study Details
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This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.