Calcium supplements seen to have no effect on body fat
body weight and body mass, claim researchers from Denmark.
Their study on teenage girls continues the debate about whether dairy foods can promote weight loss, and what the mechanism behind such an effect could be.
A previous study from Purdue University claimed that young women could burn more calories if they ate three or four dairy servings per day. However another report, also from Purdue, reported that increased dairy consumption had no effect on weight gain or loss.
The new study suggests that the benefits of dairy are not solely due to calcium content, thought earlier to be responsible for the weight loss seen in some trials.
"It is possible that the effect of calcium on the body is only exerted if it is ingested as part of a meal, or the effect may be due to other ingredients in dairy products, and calcium may simply be a marker for a higher dairy intake," wrote lead author Janne Lorenzen from the Royal Veterinary and Agricultural University, Fredriksberg.
The double-blind, placebo-controlled intervention study followed 110 young girls. The volunteers were randomly assigned to receive 500 mg of calcium per day or a placebo.
The results, published in the January issue of the American Journal of Clinical Nutrition (Vol. 83, No. 1, pp. 18-23), showed that high dietary intake of calcium was linked to lower percentage of body fat.
But calcium supplementation had no effect on body weight, body fat or height, after one year of intervention.
The researchers could not propose a mechanism, but the results appear to disprove the direct involvement of calcium to decrease levels of parathyroid hormone in the body, which in turn was suggested to increase the body's ability to burn fat.
Dairy industries in Europe and the US have been promoting milk-based products for consumers who want to slim for some time but the new findings underline that further work needs to be done to support their claims.
The EU recommended daily intake (RDI) of calcium is 800 mg, with an upper safe limit of 2500 mg.