Study Raises Early Red Flag on Potassium Bromate Exposure

Potassium bromate, an ingredient used in the U.S. baking industry to improve dough rise and handling properties, causes distinct changes in yeast DNA that are similar to the mutations found in samples of human esophageal, stomach and colorectal cancer, according to researchers from the U.S. National Institute of Environmental Health Sciences (NIEHS).

The study, published April 20 in the journal Nucleic Acids Research, does not show definitive evidence that potassium bromate causes cancer in humans, but it does raise further concern about human exposure to the already-embattled ingredient, as reported in the NIEHS June issue of Environmental Factor. Use of potassium bromate has been banned in many countries in Europe and Asia, nevertheless.

Paul Doetsch, Ph.D., deputy scientific director and senior investigator in the NIEHS Division of Intramural Research, led the study and said it “raises a red flag” around use of potassium bromate. He described a distinct pattern of change in the metabolites measured, and the way they changed (higher or lower levels) were considered to be a signature of changes brought on by exposure to potassium bromate. Moreover, these signatures were not found with other redox stress agents, according to the research team.

The study also discovered that thiol-containing antioxidants, which are normally used as a supplemental treatment for cancer patients, actually amplified the toxicity of the potassium bromate exposure. The study suggests that treatment of cancer patients with thiol-containing antioxidants might need to be re-examined in these instances.