HEALTH NEWS

Study Title:

Calcium Intake Supports Weight Management in Postmenopausal Women

Study Abstract

Abstract (provisional) | Background: It is undetermined whether calcium supplementation has an effect on obesity or body composition in postmenopausal women. The purpose of the study is to detect the effect of calcium supplementation on indices of obesity and body composition.

Methods: This is a secondary analysis of data from a population-based, double-blind, placebo-controlled, randomized trial designed to determine the effects of calcium and vitamin D on osteoporotic fractures. The cohort included 1179 postmenopausal women who were randomly assigned into one of three groups: 1) supplemental calcium (1400 mg/d or 1500 mg/d) plus vitamin D placebo (Ca-only group), 2) supplemental calcium (1400mg/d or 1500 mg/d) plus supplemental vitamin D3 (1100 IU/d) (Ca + D group), or, 3) two placebos (placebo group). After applying the exclusion criteria for this analysis, 870 subjects were included in this study. The primary outcomes for the present study were changes in body mass index, trunk fat, trunk lean, and percentage of trunk fat after calcium supplementation.

Results: Changes in trunk fat, trunk lean, and percentage of trunk fat were significantly different between the calcium intervention groups (Ca-only group or Ca + D group) and the placebo group during the trial (P<0.05). The calcium intervention groups gained less trunk fat and maintained more trunk lean when compared to the placebo group. No significant difference was observed for body mass index between groups.

Conclusion: Calcium supplementation over four years has a beneficial effect on body composition in postmenopausal women.

From press release:

Secondary analysis of data from a double-blind, placebo-controlled, randomized trial found that 1,400 or 1,500 milligrams of calcium per day, with or without vitamin D3, was associated with lower trunk fat gain and higher lean trunk mass, according to findings published in Nutrition & Metabolism.

“To the best of our knowledge, this is the first clinical trial in a population-based postmenopausal women cohort, to observe that increasing calcium intake, in the form of non-dairy calcium supplementation, can prevent gain of fat mass and loss of lean mass,” wrote the researchers, led by Lan-Juan Zhao from the Creighton University Medical Center in Omaha.

“The effect of calcium supplementation in this population-based cohort is consistent with the effect of dairy supplementation in fat and lean mass changes in obese subjects with low baseline calcium intake (< 600 mg/d),” they added.

Calcium or dairy?

The study adds to an ever growing body of science linking calcium intake, mainly from dairy products, in weight loss. The topic is a source of controversy with both camps able to quote research that supports their side and undermines the other.

Over 300m adults are obese worldwide, according to latest statistics from the WHO and the International Obesity Task Force. About one-quarter of the US adult population is said to be obese, with rates in Western Europe on the rise, although not yet at similar levels.

Study details

In order to examine if calcium supplements could affect obesity or body composition, Dr Zhao and her co-workers recruited 870 postmenopausal women with an average age of 66, an average BMI of 28.8 kg/m2. The women were randomly assigned to one of three groups: One group received two placebo capsules; the second group received calcium supplements and a placebo; and the final group received the calcium plus 1,100 IU of vitamin D3.

While no significant differences were observed for BMI between the groups, the calcium intervention groups were found to gain less trunk fat with increases of 2.4 and 1.4 percent in the calcium and calcium plus vitamin D groups, respectively, compared with the placebo group, where trunk fat increased by 5.4 per cent.
Moreover, the calcium-supplemented groups maintained their lean trunk mass to a greater extent than the placebo group, with reductions of 0.6 and 1 percent in the calcium and calcium plus vitamin D groups, respectively, compared with 2.1 percent in the placebo group.

The researchers noted that the habitual intake of the women before the trial was not low (average of over 1,000 millgrams per day). An earlier study from Canada indicated that the potential benefits of calcium supplements may be limited to women with low habitual intakes of the mineral (British Journal of Nutrition, 2009, Vol. 101, pp. 659-663).

Regarding the potential mechanism, the Canadian study proposed that calcium may affect appetite. Laval University researcher Angelo Tremblay stated: "Our hypothesis is that the brain can detect the lack of calcium and seeks to compensate by spurring food intake, which obviously works against the goals of any weight loss program. Sufficient calcium intake seems to stifle the desire to eat more."

On the other hand, a meta-analysis published last year in Obesity Reviews (Vol. 10, pp. 475-486) indicated that calcium may aid weight management by increased fat excretion in the feces.

Study Information

J. Zhou, L-J. Zhao, P. Watson, Q. Zhang, J.M. Lappe
The effect of calcium and vitamin D supplementation on obesity in postmenopausal women: secondary analysis for a large-scale, placebo controlled, double-blind, 4-year longitudinal clinical trial
Nutrition & Metabolism
2010 July
Creighton University Medical Center in Omaha.