Chromium used in dietary supplements may cause cancer: Australian researchers

A popular nutrient used in dietary supplements for weight loss and diabetes treatment may be carcinogenic and potentially cause cancer, Australian researchers said on Monday.

Trace metal chromium (III) is used in nutritional supplements by those with metabolic disorders such as insulin resistance and type-2 diabetes. It's carcinogenic cousin hexavalent chromium (VI) was made famous by the book and movie Erin Brockovich which linked elevated illnesses, including cancer, to the mineral being in the drinking water supply in the Californian town of Hinkley.

Researchers from the University of New South Wales (UNSW) and the University of Sydney treated animal fat cells with chromium (III) in a laboratory setting and found the chromium was partially carcinogenic after creating a map of every chemical element within the cell using Chicago's Argonne National Laboratory's Advanced Photon Source's high energy X-Ray beam.

"We were able to show that oxidation of chromium inside the cell does occur, as it loses electrons and transforms into a carcinogenic form," UNSW researcher Dr Lindsay Wu said.

"This is the first time oxidation was observed in a biological sample with the same results expected in human cells."

Additional experiments have been conducted that helped clarify the carcinogenic nature of the chromium (V) and chromium (VI) found in the cells.

The findings, published in the chemistry journal Angewandte Chemie, raise concerns on the risks of taking chromium dietary supplements over the long term or in high doses.

"With questionable evidence over the effectiveness of chromium as a dietary supplement, these findings should make people think twice about taking supplements containing large doses of chromium," University of Sydney Professor Peter Lay said.

"However, additional research is needed to ascertain whether chromium supplements significantly alter cancer risk."

The U.S. National Academy of Sciences estimates up to 200 micrograms of chromium is a safe and adequate daily dietary for intake.

Australian guidelines, which are currently under review, recommend 25-35 micrograms of chromium daily as an adequate intake for adults.

Popular Australian multi-vitamins range between 50 and 200 micrograms of chromium in compound form. Enditem