Randomized Study of the Effects of Vitamin D and Magnesium Co-Supplementation on Muscle Strength and Function, Body Composition, and Inflammation in Vitamin D-Deficient Middle-Aged Women

This study aimed to investigate the effects of vitamin D and magnesium co-supplementation on muscle strength and function, body composition, and inflammation in vitamin D-deficient middle-aged women. In this study, 83 healthy middle-aged women (40-55 years) with vitamin D deficiency were randomly assigned into two groups: (1) intervention: receiving a 50,000-IU vitamin D soft gel (weekly) plus a 250-mg magnesium tablet (daily); (2) control: receiving a vitamin D placebo (weekly) plus a magnesium placebo (daily), for 8 weeks. Before and after the intervention, anthropometric indices, muscle strength, muscle function, and some inflammatory markers were measured. After 8 weeks of supplementation, significant difference was observed in handgrip strength and time for Time Get Up and Go (TGUG) test between the intervention and placebo groups (P< 0.05). Regarding percentage of fat mass (FM%) and fat free mass (FFM%), and knee extension strength, there was no significant difference between the two groups at the end of intervention (P> .05). Serum 25(OH)-D levels increased significantly (P< 0.001) and its change was significantly different between the two groups, at the end of the intervention (P< 0.001). Serum level of hs-CRP decreased significantly in the intervention group compared to baseline (P< 0.001), and the change in hs-CRP was significant between the two groups at the end of the intervention (P< 0.01). Furthermore, serum level of TNF-alpha declined significantly in the intervention group compared to baseline (P< 0.001) but, no significant differences were seen between the two groups in regard of serum levels of TNF-alpha and IL-6 after the intervention (P> 0.05). Our findings show that vitamin D and magnesium co-supplementation, for 8 weeks, in healthy middle-aged women with vitamin D deficiency have beneficial impacts on muscle strength, muscle function, and probably inflammation.