The Effect of Magnesium Supplementation on Primary Insomnia in the Elderly

Nearly 50% of the elderly have insomnia، with difficulty in going to sleep، oversleeping، or feeling unrefreshed on waking up. With aging، several changes can occur that place one at risk of insomnia. The objective of the present study was to determine the efficacy of magnesium supplementation -the natural NMDA antagonist and GABA agonist- to improve insomnia in the elderly. A double blind randomized clinical trial was conducted on 46 elderly subjects، randomly allocated into the magnesium and the placebo group and received 500 mg magnesium and placebos daily for 8 weeks، respectively. Questionnaires of insomnia severity index، physical activity، and sleep-log were completed at baseline and after the intervention period. Anthropometric and dietary confounding factors were obtained using 24h recall for 3 days. Blood samples were taken at baseline and after the intervention period for analysis of serum magnesium، renin، melatonin، and cortisol. Statistical analyses were performed using SPSS (V. 19) and N4 software; P-value<0. 05 was considered as statistically significant. No significant differences were observed in assessed variables between the two groups at the baseline. According to the present research magnesium supplementation significantly increased sleep time (P=0. 002)، sleep efficiency (P=0. 03)، concentration of serum renin (P<0. 001) and melatonin (P=0. 007); besides، it significantly decreased ISI score (P=0. 006)، sleep onset latency (P=0. 02)، and serum cortisol concentration increase (P=0. 008) in the magnesium group. Although total sleep time (P=0. 37)، waking up length of time (P=0. 08)، and serum magnesium concentration P=0. 06) did not reveal any significant difference. Supplementation of magnesium appears to improve different measures effective in insomnia in the elderly.