Effect of oral magnesium supplementation on physical performance in healthy elderly women involved in a weekly exercise program: a randomized controlled trial

Magnesium deficiency is associated with poor physical performance, but no trials are available on how magnesium supplementation affects elderly people's physical performance. The aim of our study was to investigate whether 12 wk of oral magnesium supplementation can improve physical performance in healthy elderly women. In a parallel-group, randomized controlled trial, 139 healthy women (mean ± SD age: 71.5 ± 5.2 y) attending a mild fitness program were randomly allocated to a treatment group (300 mg Mg/d; n = 62) or a control group (no placebo or intervention; n = 77) by using a computer-generated randomization sequence, and researchers were blinded to their grouping. After assessment at baseline and again after 12 wk, the primary outcome was a change in the Short Physical Performance Battery (SPPB); secondary outcomes were changes in peak torque isometric and isokinetic strength of the lower limbs and handgrip strength. A total of 124 participants allocated to the treatment (n = 53) or control (n = 71) group were considered in the final analysis. At baseline, the SPPB scores did not differ between the 2 groups. After 12 wk, the treated group had a significantly better total SPPB score (Δ = 0.41 ± 0.24 points; P = 0.03), chair stand times (Δ = -1.31 ± 0.33 s; P < 0.0001), and 4-m walking speeds (Δ = 0.14 ± 0.03 m/s; P = 0.006) than did the control group. These findings were more evident in participants with a magnesium dietary intake lower than the Recommended Dietary Allowance. No significant differences emerged for the secondary outcomes investigated, and no serious adverse effects were reported. Daily magnesium oxide supplementation for 12 wk seems to improve physical performance in healthy elderly women. These findings suggest a role for magnesium supplementation in preventing or delaying the age-related decline in physical performance. This trial was registered at clinicaltrials.gov as NCT01971424.