What you may have heard
Potassium bromate is used in baking and is linked to cancer.
What science tells us
Potassium bromate is a flour improver used in baking to strengthen dough, increase bread volume, and produce a fine crumb structure. It is commonly found in white flour, bread, and rolls. Potassium bromate has been shown to cause cancer in animals. While most of the bromate breaks down into the less harmful bromide during baking, any remaining bromate poses a small cancer risk to consumers.
Potassium bromate has been banned in many countries worldwide, but it is still permitted in the US and Japan. In October 2023, California Governor Gavin Newsom signed a bill into law banning the use of potassium bromate, along with three other common food additives (brominated vegetable oil, propylparaben, and Red Dye No. 3). The California Food Safety Act takes effect in 2027, making it illegal to sell, distribute, and manufacture these additives in the state.
Epidemiological Evidence
Epidemiological studies have linked potassium bromate to an increased risk of cancer in animals, but direct evidence in humans is limited.
Laboratory Evidence/Supporting Evidence
A 1983 study published in the Journal of the National Cancer Institute involved giving rats different concentrations of potassium bromate in their drinking water. The group exposed to the highest concentration experienced the shortest survival times and had significantly higher incidences of kidney tumors and mesotheliomas of the peritoneum (a type of cancer affecting the lining of the abdominal cavity) in males compared to the control group. The study concluded that potassium bromate was carcinogenic to rats when administered orally (Kurokawa et al., 1983).
IARC Carcinogen Classification:
Classified as Group 2B carcinogen (possibly carcinogenic to humans).
How to reduce your risk
Avoid baked goods that list potassium bromate as an ingredient. Choose products labeled as bromate-free. Opt for bread and baked goods made without this additive.
Bottom line
Potassium bromate is a known carcinogen in animals, and avoiding it can reduce cancer risk. Selecting bromate-free baked goods is a simple step to protect your health and reduce exposure to harmful additives.
One way to know what is in your food is to cook and bake it at home. Try some cancer-mindful recipes from the American Instiute for Cancer Research.