[Effect of magnesium supplementation on calorie intake and weight loss of overweight or obese insomniac elderly subjects: a double-blind randomized clinical trial]

ABSTRACT

There is evidence suggesting an association between insomnia and obesity and probable beneficial effects of magnesium supplementation on insomnia. The objective of this study was to determine the effects of dietary magnesium supplementation on the energy intake and weight reduction of insomniac overweight or obese elderly subjects. A double-blind randomized clinical trial was conducted on 46 overweight or obese subjects randomly allocated into the magnesium or the placebo group, receiving, daily for 8 weeks, either 500 mg magnesium or a placebo, respectively. Using appropriate questionnaires, data were collected on insomnia [insomnia severity index = ISI], physical activity, and sleep-log at baseline and at the end of the intervention period. In addition, information was obtained on anthropometric confounding factors and daily intakes of magnesium, calcium, potassium, caffeine, energy form carbohydrates, fat and protein, and total daily energy intake using the 24-hr dietary recall questionnaire for 3 days. The N4 and SPSS software version 16 were used for data analysis, the level of significance being a p-value < 0.05. No significant differences were observed in the assessed variables between the two groups at baseline. As compared to the placebo group, in the experimental group diatery magnesium supplementation brought about statistically significant increases in sleep duration and sleep efficiency, as well as significant decreases in the total energy intake and energy from carbohydrate and fat. The total length of time in bed, morning awakening time, energy from protein, serum magnesium concentration, or body weight were not different between the experimental and the placebo groups. In this study diatery magnesium supplementation resulted in improvements in sleep indices and a decrease in energy intake in elderly subjects. However, it had no beneficial effect on their body weight