Study Suggests Boning up on Copper While Dieting

People who are overweight or obese are vulnerable to losing unhealthful amounts of calcium from their bones when they go on weight-loss diets. But a study by Agricultural Research Service (ARS) scientists suggests that consuming about three times the recommended amount of dietary copper may help women retain calcium in their bones when dieting.

The study was led by ARS physiologist Henry C. Lukaski and was reported in abstract form at a meeting sponsored by the American Society for Clinical Nutrition. Lukaski is assistant director of the Grand Forks Human Nutrition Research Center in Grand Forks, N.D.

Of the women who completed the study, in addition to the copper present in the foods they ate, just under half received daily supplements of 3 milligrams (mg) of copper. The others received supplements of only 1.2 mg. All participants--who ranged in age from 25 to 35 years old--were then put on a weight-loss diet for 4 months.

During the study, the researchers tracked the participants’ loss of calcium with isotopes. The study showed that the women who were given 3 mg of additional copper were more likely to retain calcium in their bones.

The current Recommended Dietary Allowance (RDA) for copper is 0.9 mg for women older than 19 years. ARS findings provide science-based data to experts who establish and update the RDAs.

This study suggests the current RDA for copper may not be adequate during weight loss.

Good sources of copper include green vegetables, mushrooms, seafood, liver, nuts, seeds, wheat bran, some cereals and whole grains.

Read more about the research in Agricultural Research magazine’s March 2006 issue, which focuses on ARS obesity research.

ARS is the U.S. Department of Agriculture's chief scientific research agency.