A combination of calcium plus vitamin D during weight loss in overweight and obese women could improve blood cholesterol levels, says new research from Canada.
Researchers from the University of Laval recruited 63 women with an average BMI of kg per sq. m. and assigned them to either a daily calcium (600mg) plus vitamin D (200IU) supplement or placebo for 15 weeks.
Calcium, from supplements or dairy, has been linked to weight loss amongst various population groups, but the area remains controversial and results inconsistent. Indeed, two studies from Purdue University reported conflicting claims, with one reporting that young women could burn more calories if they ate three or four dairy servings per day, while the other reported that increased dairy consumption had no effect on weight gain or loss.
A study last year, published in the Journal of the American Dietetic Association (Vol. 106, pp. 1066-1073), brought the focus of the debate back to calcium with the researchers concluding that calcium, in the form of supplements, could be beneficial for weight control, but only in women.
How the research was done
The new study, published in the current issue of the American Journal of Clinical Nutrition, lead author Geneviève Major from the Department of Social and Preventive Medicine at the university’s Faculty of Medicine reports that the combination of the vitamin and calcium may improve cholesterol levels during weight loss.
The randomised, double-blind controlled trial recruited 63 women with daily calcium intakes of less than 800mg per day, which is the EU recommended daily intake (RDI). They were assigned to either the calcium plus vitamin D group or placebo, with both groups adhering to a weight loss plan whereby their energy intake was restricted by 700kcal per day.
After 15 weeks of supplementation, the researchers report that the calcium supplements significantly improved the total:HDL cholesterol ratio, reported to be the most specific lipid risk factor for CVD. Improvements in the ration of LDL (so-called ‘bad’ cholesterol) to HDL (so-called ‘good’ cholesterol) also improved. The improvements in blood lipid levels were independent of fat mass and waist circumference, they said.
“A tendency for more beneficial changes in HDL cholesterol, triacylglycerol, and total cholesterol was also observed in the calcium + [vitamin] D group,” said the researchers.
A number of mechanisms at work
Professor Angelo was not available for comment prior to publication, but told Reuters Health that a number of mechanisms may be behind the apparent effects, including the role of calcium to interfere with fat absorption in the gut, boosting the body’s ability to burn fat, or potentially having a satiety role.
“Consumption of calcium + D during a weight-loss intervention enhanced the beneficial effect of body weight loss on the lipid and lipoprotein profile in overweight or obese women with usual low daily calcium intake,” concluded the researchers.
The combination of vitamin D and calcium has long been recommended to reduce the risk of bone fracture for older people, particularly those at risk of or suffering from osteoporosis. - (Decision News Media, January 2006)
New break for bone products?
Calcium helps women to lose weight