But there's preliminary evidence that chromium picolinate causes severe damage to chromosomes in hamsters' ovary cells. A new study builds on earlier findings that hamster cells grown in a laboratory -- when exposed to chromium picolinate -- develop mutations in the cells' DNA.
But one chromium manufacturer says it has conducted extensive human tests. "Chromium picolinate has been shown completely safe," says James Komorowski, MS, director of research and development at Nutrition 21 in Purchase, N.Y. Nutrition 21 is the leading developer and marketer of chromium-based nutritional supplements.
The substance, which has been on the market for 10 years, has also been tested and found safe by the USDA, he tells WebMD.
The FDA considers chromium picolinate a nutritional supplement and therefore does not regulate it.
The hamster cell study, published in the journal Mutation Research, builds on studies dating to 1995, according to lead author Diane Stearns, assistant professor of biochemistry at Northern Arizona University.
"Our first study showed chromosome damage, and our second study has taken it one step further by showing that this damage leads to mutations," she says in a news release. "Mutations in certain genes may lead to cancer."
The current findings are "more indicative" of this cancer-causing potential, Stearns says. "We are currently determining the actual type of DNA damage that causes the mutations in order to better understand the relevance of our results to humans who are taking these supplements."
In her study, Stearns exposed live hamster ovary cells to high dosages chromium picolinate and found a high incidence of mutated cells.
Animal tissue studies like Stearns' "cannot be used to conclude that something causes cancer, " says Komorowski.
"There are studies that can be used to determine if a substance is toxic or not, and Nutrition 21 has done those studies, and chromium picolinate has been shown completely safe," he tells WebMD.
Stearns admits that the doses used in her study were higher than one would get from a few pills. "However the doses were within international guidelines for genotoxicity testing," she says. "Also, it is known that chromium can accumulate in the body; therefore, we caution against taking excessive doses of chromium picolinate for long periods of time."
The doses are indeed "over 50,000 times higher than the level of chromium a human would have in their blood," counters Komorowski. "Those doses are so high, she had to use acetone to get the chromium picolinate to go into solution, so you're using a toxic agent and mixing it with a huge dose of chromium picolinate and exposing it directly to ovary cells."
Stearns found that 58 of 1 million cells had DNA damage, Komorowski points out. "You can't take that and say humans should be concerned."
Nutrition 21 has conducted "numerous clinical studies involving over 3,000 subjects -- in studies between three months and one year in duration -- and there have been absolutely no side effects," Komorowski tells WebMD.
The USDA toxicity studies also used extremely high doses chromium "but found absolutely no damage and concluded that chromium picolinate was safe," he says. A safety paper published by the USDA comments on animal cell studies like Stearns,' citing "that one cannot extrapolate from a hamster tissue culture what could happen in humans," says Komorowski. "They say her studies are 'extremely questionable.'"