Background: Obesity and diabetes are the most important problems of public health. Evidence from molecular animal research and epidemiologic investigations indicate that calcium intake may have an influence on body composition, weight and insulin resistance. The objective of this study was to determine the effects of calcium supplementation on body composition, weight, insulin resistance and blood pressure in the face of calorie restriction in obese adults.
Methods: A double blind randomized placebo-controlled trial on 40 adults with Body Mass Index > 25kg/m(2) was conducted. Subjects were maintained for 24 weeks on a balanced deficit diet (-500 kcal/d deficit) and randomly assigned into two groups with 1000 mg ca/d as calcium carbonate or placebo.
Results: There were no significant differences in variables at the 12th and 24th week between the two groups. The lean mass showed no significant increase in the calcium group at the 12th week compared to baseline and in placebo group at the 24th week compared to the 12th week. The insulin concentration showed a significant decrease in the calcium group at the 12th week compared to the baseline (p < 0.05). The diastolic blood pressure had a significant decrease at the 24th week compared to the 12th week in both groups (p = 0.013-0.009).
Conclusions: Results from this study suggest that 24 weeks of supplementation with 1000 mg ca/d did not have any effect on weight, body composition, insulin resistance and blood pressure beyond what can be achieved in an energy restricted diet in obese adults.
Keywords: Body Composition; Calcium Supplement; Insulin Resistance; Obesity; Weight Loss.