Effects of calcium supplementation on body weight and adiposity in overweight and obese adults: a randomized trial

Ann Intern Med. 2009 Jun 16;150(12):821-9, W145-6. doi: 10.7326/0003-4819-150-12-200906160-00005.


Background: Some data suggest that increasing calcium intake may help prevent weight gain.

Objective: To test the hypothesis that calcium supplementation can prevent weight gain in persons who are overweight or obese.

Design: Randomized, placebo-controlled trial. Randomization was computer-generated, and allocation was assigned by pharmacy personnel who prepared intervention and placebo capsules. Participants, providers, and those who assessed outcomes were blinded to study group assignment.

Setting: Single research center.

Participants: 340 overweight (body mass index [BMI], 25 to <30 kg/m(2)) and obese (BMI > or =30 kg/m(2)) adults (mean age, 38.8 years [SD, 10.5]).

Intervention: Calcium carbonate (elemental calcium, 1500 mg/d) (n = 170) or placebo (n = 170) with meals for 2 years.

Measurements: Changes in body weight and fat mass (primary outcomes).

Results: Seventy-five percent of participants completed the trial (78% received calcium; 73% received placebo). There were no statistically or clinically significant differences between the calcium and placebo groups in change in body weight (difference, 0.02 kg [95% CI, -1.64 to 1.69 kg]; P = 0.98), BMI (difference, 0.32 kg/m(2) [CI, -0.41 to 1.02 kg/m(2)]; P = 0.39), or body fat mass (difference, 0.39 kg [CI, -1.04 to 1.92 kg]; P = 0.55). Parathyroid hormone concentrations decreased in the calcium group compared with the placebo group (difference, -0.71 pmol/L [CI, -1.28 to -0.13 pmol/L]).

Limitation: The study took place at a research center, and its sample was mostly women.

Conclusion: Dietary supplementation with elemental calcium, 1500 mg/d, for 2 years had no statistically or clinically significant effects on weight in overweight and obese adults. Calcium supplementation is unlikely to have clinically significant efficacy as a preventive measure against weight gain in such patients.

Trial registration: ClinicalTrials.gov NCT00030238.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Adiposity
  • Adolescent
  • Adult
  • Aged
  • Body Mass Index
  • Calcium Carbonate / administration & dosage*
  • Calcium, Dietary / administration & dosage*
  • Dietary Supplements*
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Middle Aged
  • Obesity / diet therapy*
  • Overweight / diet therapy*
  • Patient Compliance
  • Sensitivity and Specificity
  • Surveys and Questionnaires
  • Weight Loss
  • Young Adult


  • Calcium, Dietary
  • Calcium Carbonate

Associated data

  • ClinicalTrials.gov/NCT00030238