Background & Objective: Advances in public health and control of infectious diseases have led to increased number of elderly people in the world including Iran. Thus serious concerns exist in terms of age-related diseases . Consequently, Iran’s ministry of health has chosen “ageing and health” as the theme for 2012 along with WHO. Psychological disorders�are among the most prevalent diseases in elderly people. Recent studies suggest a two-way relationship between some psychological disorders and insomnia. Also there is evidence implying magnesium role in improvement of aforementioned disorders. The objective of this study was to determine the effects of dietary magnesium supplementation on mental health in insomniac elderly subjects.

  Methods: A double-blind randomized clinical trial was conducted on 46 insomniac elderly subjects randomly allocated into the magnesium or the placebo group, receiving daily for 8 weeks either 500 mg magnesium or a placebo, respectively. SCL-90-R and ISI questionnaires were conducted at baseline and at the end of the intervention period. Serum magnesium and cortisol levels were also determined in the patients. In addition, information was obtained on anthropometric confounding factors and daily intake of magnesium, calcium, potassium and caffeine using 24-hr dietary recall questionnaire for 3 days. The N4 and SPSS19 were used for data analysis.

  Results: No significant differences were observed in assessed variables between the two groups at baseline. As compared to the placebo group, in the experimental group, dietary magnesium supplementation brought about statistically significant decreases in GSI, PST, PSDI, ISI scores as well as somatization , anxiety, psychoticism , and depression symptoms and serum cortisol concentration. While the obsessive-compulsive , interpersonal sensitivity, hostility , phobic anxiety, paranoid ideation scores and serum magnesium concentration were not different between the experimental and the placebo groups.

  Conclusion: In this study dietary magnesium supplementation resulted in improvements in insomnia severity index and some indices of mental health.