By Margarita Nahapetyan
It was believed that individuals who eat more dairy products have lower weight and are losing weight much easier. However, according to the new study from the National Institutes of Health, which appears to be the best research to date on the matter, has found that dietary supplementation with calcium have no effect on total weight, body mass index (BMI), or body fat mass in overweight and obese people.
Two years of calcium supplementation led to no clinically or statistically significant change in body weight or body fat, said Dr. Jack A. Yanovski, M.D., Ph.D., of the National Institutes of Health. "Even though there may be other important reasons, such as fracture prevention, to recommend dietary calcium supplementation, the conclusion is that the extant data suggest that it is unlikely to have clinically significant efficacy as a preventive measure against weight gain in patients who are already overweight or obese," he added.
Some sources have suggested that increasing calcium intake may help fight weight gain. Some others have speculated that calcium can be used in combination with fatty acids in the intestine in order to form insoluble soaps that are not being absorbed, or that low dietary calcium results in an increased adiposite triglyceride deposition.
However, the evidence has been inconsistent. So the investigators set out to carry out a randomized controlled trial with an involvement of 340 overweight and obese adult patients with an average age of 38.8 years. All the participants were randomly assigned into 2 groups, with some receiving either 1,500 mg of calcium carbonate on a daily basis, and the ones in a control group received just a placebo. Patients were given the capsules at mealtime. Of all the study subjects, 39 per cent were overweight and 61 per cent were obese. There were 245 women and 95 men. The study was conducted from April 2002 to January 2004.
Seventy-five per cent of participants completed the trial. The results revealed that two years later there were no statistically or clinically significant differences between the participants in the calcium and placebo groups in change in body weight, body mass index (BMI) or body fat mass. No significant differences were also observed in abdominal circumference, hip circumference, or triceps skinfold thickness. The patients did not show any differences in general health, mood, stress, physical activity, or hunger according to a questionnaire. However, the experts found that parathyroid hormone concentrations significantly dropped in the calcium group participants, when compared to their counterparts in the placebo group -- a signal that patients were sticking to their calcium regimens.
The investigators noted that many studies that have been conducted in the previous years on the matter of calcium supplementation, have also included weight-loss programs, and have had mixed results. "We believe all the data are consistent in suggesting limited efficacy for preventing weight gain among overweight or obese patients," they said.
The new experiment had a few limitations, such as not including a high-dairy calcium diet. Some experts have suggested that dairy products, and not just calcium intake, may have result in greater effects on body weight. Also, the vast majority of the study participants were women, and thus, the results may not be generalizable to men.
In the conclusion, Dr. Yanovski and his colleagues said that it is unlikely that calcium supplementation will have clinically significant effect when it comes to using it as a preventive measure against weight gain in overweight individuals.
The findings are reported in the June 16 issue of the Annals of Internal Medicine journal.