Influences of Vitamin D and Iron Status on Skeletal Muscle Health: A Narrative Review

There is conflicting evidence of the roles vitamin D and iron have in isolation and combined in relation to muscle health. The purpose of this narrative review was to examine the current literature on the roles that vitamin D and iron have on skeletal muscle mass, strength, and function and how these nutrients are associated with skeletal muscle health in specific populations. Secondary purposes include exploring if low vitamin D and iron status are interrelated with skeletal muscle health and chronic inflammation and reviewing the influence of animal-source foods rich in these nutrients on health and performance. PubMed, Scopus, SPORT Discus, EMBAE, MEDLINE, and Google Scholar databases were searched to determine eligible studies. There was a positive effect of vitamin D on muscle mass, particularly in older adults. There was a positive effect of iron on aerobic and anaerobic performance. Studies reported mixed results for both vitamin D and iron on muscle strength and function. While vitamin D and iron deficiency commonly occur in combination, few studies examined effects on skeletal muscle health and inflammation. Isolated nutrients such as iron and vitamin D may have positive outcomes; however, nutrients within food sources may be most effective in improving skeletal muscle health.

Automated summary

There is conflicting evidence regarding the roles of vitamin D and iron in muscle health, with vitamin D having a positive effect on muscle mass and iron having a positive effect on aerobic and anaerobic performance. However, studies have reported mixed results for both vitamin D and iron on muscle strength and function. While deficiency in both vitamin D and iron commonly occur together, there is limited research on their effects on muscle health and inflammation. Nutrients within food sources may be more effective in improving skeletal muscle health compared to isolated nutrients such as iron and vitamin D.