Vitamin D plus protein helps strengthen but not bulk up muscle in sarcopenia

In patients with sarcopenia, vitamin D supplementation in combination with protein increases muscle strength but falls short of improving muscle mass or performance, according to the results of a systematic review and meta-analysis.

Initial search across multiple online databases yielded 1,164 studies, eight of which met the eligibility criteria for qualitative and quantitative analysis. The total population comprised 776 patients.

Pooled data showed that supplementation with vitamin D (100–1,600 IU/day) plus protein (10–44 g/day) produced a beneficial effect on muscle strength, as demonstrated by an improvement in handgrip strength (standardized mean difference [SMD], 0.38, 95 percent confidence interval [CI], 0.18–0.47; p=0.04; I², 76.2 percent) and a decrease in the sit-to-stand time (SMD, 0.25, 95 percent CI, 0.06–0.43, p=0.007; I², 0 percent) when compared with placebo.

However, the intervention had a borderline significant effect on muscle mass, which was assessed by skeletal muscle index (SMD, 0.25, 95 percent CI, –0.006 to 0.51; p=0.05; I², 0 percent).

Finally, appendicular skeletal muscle mass or muscle performance, as evaluated by walking speed, remained unchanged on vitamin D plus protein.

Vitamin D exerts direct and indirect effects on skeletal muscle, and lack of this nutrient has been shown to accelerate the muscle atrophy induced by immobilization. Aside from vitamin D, exercise is another important factor associated with sarcopenia. Resistance exercise has been widely accepted to prevent and reverse sarcopenia. [J Cachexia Sarcopenia Muscle 2020;11:678-689]