Background: Clinical trials designed to examine the effects of calcium supplementation on abdominal obesity have had ambiguous results.
Aims: This study aimed to evaluate, during energy restriction, the effects of a high-calcium diet (HCD) on measures of abdominal obesity and cardiometabolic risk factors in Brazilian obese subjects of multiethnic origin.
Methods: We conducted a randomised clinical trial. Fifty obese subjects of both sexes, aged 22–55 years, with stable body weight and a low calcium intake were randomised into the following outpatient dietary regimens: (i) a low-calcium diet (LCD; < 500 mg/day) or (ii) a HCD [1200–1300 mg/day, supplemented with non-fat powdered milk (60 g/day)]. Both groups followed an energy-restricted diet (−800 kcal/day) throughout the study (16 weeks).
Results: Thirty-nine participants completed the study. After 16 weeks of energy restriction, a significant reduction was observed in all anthropometric parameters, metabolic variables (except for high-density lipoprotein cholesterol) and blood pressure levels in both the groups. Insulin was significantly reduced only in the HCD group. Subjects on the HCD compared with those on the LCD exhibited a greater reduction in waist circumference (p = 0.002), waist-to-hip ratio (p = 0.0001), diastolic blood pressure (p = 0.04) and mean blood pressure (p = 0.03).
Conclusions: Our study suggests that increased calcium intake may enhance the beneficial effects of energy restriction on abdominal obesity and blood pressure.