Postmenopausal women who take calcium and vitamin D supplements may gain less weight than those who do not, although the overall effect is small, according to a report in the May 14 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. The benefit is greater in those who had not previously been getting the daily recommended amount of calcium.
"Because weight loss or prevention of weight gain is likely to have significant health benefits for middle-aged women, early to middle menopause may be a critical period of life in which to slow the trajectory of weight gain," the authors note as background information in the article. Some evidence suggests that calcium and vitamin D may play a role in effective weight management. These nutrients may stimulate the breakdown of fat cells and suppress the development of new ones.
Bette Caan, Dr.P.H., of Kaiser Permanente Northern California, Oakland, and colleagues studied 36,282 postmenopausal women age 50 to 79 who were enrolled in the Women's Health Initiative clinical trial. The women were randomly assigned to receive a dose of 1,000 milligrams of calcium plus 400 international units of vitamin D (18,176 women) or placebo (18,106 women) daily. They were weighed each year for approximately seven years.
At the beginning of the study, 39.63 percent of the women met current recommended daily intake of 1,200 milligrams of calcium, 53.94 percent reported taking any calcium supplements and 28.95 percent reported taking supplements of 500 milligrams of calcium or more. At the end of the study, women who took the supplements weighed an average of 0.28 pounds less than those who did not.
Among women who were getting less than the recommended amount of calcium daily before the study, those who took the supplements weighed an average of 0.42 pounds less than those who did not. After three years, when compared to women taking placebo, these women had a lower risk of gaining weight in both small amounts (2.2 to 6.6 pounds) and moderate amounts (more than 6.6 pounds) and had a higher likelihood of maintaining a stable weight (within 2.2 pounds of starting weight) or losing weight (more than 2.2 pounds).
"Prevention of weight gain is an important public health goal, and caloric restriction and daily physical activity should still be considered the basic tenets of weight management," the authors conclude. "Further research should be undertaken to address the effect of calcium supplementation combined with caloric restriction and physical activity on weight gain prevention."
(Arch Intern Med. 2007;167:893-902. Available pre-embargo to the media at www.jamamedia.org.)
Editor's Note: This study was supported by the National Heart, Lung, and Blood Institute, Department of Health and Human Services. Many clinical centers received assistance from the General Clinical Research Center program of the National Center for Research Resources. The active study drug and placebo were supplied by GlaxoSmithKline Consumer Healthcare. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.