Most calcium sources naturally contain lead. That may explain why two studies of calcium supplements last year found many brands to be laced with lead. The findings fueled concern about the potential for subtle lead poisoning, especially in children or in women taking calcium to prevent osteoporosis.
Australian scientists now argue that risks of such poisoning may not be as grave as suspected. They find that the body absorbs less lead when the metal is taken with calcium.
As a geochemist, Brian L. Gulson of Macquarie University in Sydney knew that calcium competes with lead for binding to molecules in cells. So, he and his coworkers pilot tested how much of a supplement's lead people actually absorb. They gave roughly 1 gram of calcium daily to 15 men and women for 6 months. Seven received tablets of calcium carbonate; the rest got a supplement made of three other forms of calcium.
The lead in the calcium carbonate tablets, which were made from U.S. calcium