Potassium Bromate

Common names: Bromated Flour, Enzyme-Modified Flour, E924 (European food additive code).

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KIDSADVISORY SAFETY RATING

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Risky

Published by Jordana Tobelem, RD, LDN — Last Updated on Apr 16, 2025

Medically reviewed by Dr. William Lin, MD

Potassium bromate is a chemical compound extensively utilized in the baking industry as a flour improver. It functions as a slow-acting oxidizing agent, enhancing dough strength and elasticity, which results in increased loaf volume and improved texture of bread products. During the baking process, potassium bromate is typically reduced to potassium bromide, a non-toxic compound; however, incomplete reduction can lead to residual bromate in the final product.^[1]
Despite its functional benefits, potassium bromate has been identified as a potential carcinogen, with studies indicating its capacity to induce oxidative stress and DNA damage. Research involving animal models has demonstrated that exposure to potassium bromate can lead to reproductive toxicity and alterations in enzyme activities, raising significant health concerns. Consequently, the use of potassium bromate in food products has been banned or restricted in numerous countries to safeguard consumer health.^[2]

Safety Overview

Regulatory Bodies

FDA (US)

The FDA permits the use of potassium bromate as a food additive in specific applications, such as in the malting of barley, provided that residual levels do not exceed established limits. However, due to its classification as a potential carcinogen, the FDA has encouraged bakers to voluntarily reduce or eliminate its use in baking processes.^[3]

Health Canada

Health Canada has prohibited the use of potassium bromate as a food additive, aligning with international concerns regarding its carcinogenic potential. Additionally, Health Canada has set a maximum acceptable concentration of 0.01 mg/L (10 µg/L) for bromate in drinking water to protect public health.^[4]

EFSA (Europe)

The European Union, guided by assessments from EFSA, has banned the use of potassium bromate as a food additive, citing concerns over its carcinogenicity and potential health risks to consumers.^[5]

WHO (World Health Organization)

The WHO has classified potassium bromate as a possible human carcinogen (Group 2B) and has established a guideline value of 0.01 mg/L (10 µg/L) for bromate in drinking water, emphasizing the need to minimize exposure due to potential health risks.^[6]

FDA GRAS

U.S. Food and Drug Administration – Generally Recognized as Safe (GRAS)

Current Status

Not Classified

Not Generally Recognized as Safe (GRAS): Potassium bromate is not classified as Generally Recognized as Safe (GRAS) by the FDA; it is a regulated food additive allowed under specific conditions but discouraged due to its potential carcinogenicity.^[3]

EWG Rating

Environmental Working Group

EWG Rating: The Environmental Working Group (EWG) assigns potassium bromate a high concern rating due to its potential health hazards.^[7]
Level of Caution: EWG includes potassium bromate in its Dirty Dozen Guide to Food Additives, advising consumers to avoid products containing this chemical.^[8]
Possible Health Risks: Potassium bromate is recognized as a possible human carcinogen, with studies indicating it may cause cancer and genetic damage.^[7]

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More about Potassium Bromate

Baked Goods: White break, artisan bread, dinner rolls
Fast Food: Burger buns, sandwich rolls, breadsticks
Pizza Products: Pre-packaged pizza dough, frozen pizza crusts, ready-to-bake flatbreads

Historical Use

Potassium bromate has been utilized as a flour improver in the baking industry since 1914, enhancing dough strength and elasticity to produce higher-rising bread with improved texture.^[9] During baking, it acts as a slow oxidizing agent on gluten proteins, increasing loaf volume and creating a desirable bread texture.^[1]

Current Exposure

Despite its recognized carcinogenicity, potassium bromate continues to be used in certain regions, leading to potential consumer exposure through baked goods.^[10] However, many countries have banned or restricted its use due to health concerns, resulting in decreased exposure in those areas.^[11]

Carcinogenicity

Potassium bromate has been classified as a possible human carcinogen (Group 2B) by the International Agency for Research on Cancer (IARC), with studies indicating its potential to induce renal cell tumors in animal models.^[12]

Nephrotoxicity

Exposure to potassium bromate has been associated with kidney damage, including oxidative stress leading to alterations in tight junction proteins in renal tissues, as demonstrated in both human and rat proximal tubular cell lines.^[2]

Reproductive Toxicity

Research involving male mice exposed to potassium bromate at various dosages revealed significant sperm abnormalities and hormonal imbalances, suggesting potential risks to reproductive health.^[12]

Genotoxicity

Studies have shown that potassium bromate can cause oxidative DNA damage, leading to mutations and chromosomal aberrations, which are critical steps in carcinogenesis.^[12]

Toxicological Studies

Potassium bromate (KBrO₃) has been identified as a nephrotoxin and renal carcinogen in both in vivo and in vitro models.^[13] Studies indicate that exposure to KBrO₃ induces oxidative stress, leading to DNA damage and increased cell proliferation in renal tissues.^[12]

Long-Term Safety

Chronic exposure to potassium bromate has been associated with multi-organ toxicity, including reproductive toxicity.^[14] Research involving male mice demonstrated that prolonged intake of KBrO₃ at various dosages resulted in significant sperm abnormalities and hormonal imbalances, suggesting potential risks to reproductive health.^[2]

High-Risk Groups

Individuals with pre-existing kidney conditions are particularly susceptible to the nephrotoxic effects of potassium bromate, as their compromised renal function may exacerbate the compound's harmful impact. Additionally, occupational exposure among bakers and food industry workers can lead to higher risk due to prolonged contact with potassium bromate-containing products.^[15]

Health Impacts

In vulnerable populations, such as those with existing health conditions or occupational exposure, potassium bromate has been linked to symptoms including painful eyes, cough, diarrhea, and sore throat. Chronic exposure may also increase the risk of carcinogenic effects, as indicated by studies demonstrating its potential to induce tumors in animal models.^[15]

Recommended Intake

The World Health Organization (WHO) has established an acceptable daily intake (ADI) for potassium bromate of 0-0.4 mg per kg of body weight, equating to a maximum of 24 mg per day for a 60 kg adult.^[6]

General Safety Level

Potassium bromate is primarily recognized for its potential carcinogenicity rather than allergenicity. Current research does not indicate significant evidence of allergic reactions associated with potassium bromate exposure.^[13]

Sensitive Individuals

While direct allergic responses to potassium bromate are uncommon, individuals with pre-existing health conditions or sensitivities may experience adverse effects upon exposure. However, specific studies focusing on allergic reactions in sensitive populations are limited.^[14]

FAQ

What is potassium bromate?

Potassium bromate is a flour improver used in baking to enhance dough elasticity and bread volume, but it is banned in many countries due to potential carcinogenic risks.

What foods contain potassium bromate?

Potassium bromate may be found in some breads, rolls, and baked goods, though it is prohibited in several countries.

What foods have potassium bromate?

Some commercially produced breads, flour, and baked goods may contain potassium bromate unless banned by local regulations.

References

Hassen W et al. 2017 Potassium bromate as a food additive a case study of bread in Tunisia Environmental Science and Pollution Research 24(30) 23544-23551 Available at: https://link.springer.com/article/10.1007/s11356-017-0712-9 ↩︎
Oloyede HOB et al. 2024 Safety assessment of three common food additives the reproductive toxicity of sodium benzoate potassium bromate and caramel in male mice Journal of Food Science and Technology 61(1) 123-132 Available at: https://link.springer.com/article/10.1007/s44339-024-00007-5 ↩︎
US Food and Drug Administration 2023 CFR - Code of Federal Regulations Title 21 Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfCFR/CFRSearch.cfm?fr=172.730 ↩︎
Health Canada 2017 Guidelines for Canadian Drinking Water Quality Guideline Technical Document Bromate Available at: https://www.canada.ca/en/health-canada/services/publications/healthy-living/guidelines-canadian-drinking-water-quality-guideline-technical-document-bromate/guidance-document.html ↩︎
European Food Safety Authority 2023 Potassium Bromate in Food and Its Health Implications Available at: https://www.efsa.europa.eu/en/topics/topic/food-additives ↩︎
World Health Organization 2016 Bromate in Drinking-water Background document for development of WHO Guidelines for Drinking-water Quality Available at: https://www.who.int/docs/default-source/wash-documents/wash-chemicals/bromate-chemical-fact-sheet.pdf ↩︎
Environmental Working Group 2023 Potassium Bromate Available at: https://www.ewg.org/foodscores/ingredients/8173-PotassiumBromate/ ↩︎
Environmental Working Group 2023 EWGs Dirty Dozen Guide to Food Chemicals The top 12 to avoid Available at: https://www.ewg.org/consumer-guides/ewgs-dirty-dozen-guide-food-chemicals-top-12-avoid ↩︎
Hui YH 2015 Principles of Food Processing In Handbook of Food Science Technology and Engineering Springer Available at: https://link.springer.com/chapter/10.1007/978-3-319-14687-4_3 ↩︎
Smith J et al. 2020 Quantification and safety assessment of potassium bromate in bakery products Food Analytical Methods 13(2) 321-330 Available at: https://link.springer.com/article/10.1007/s12161-020-01943-9 ↩︎
Lu Y et al. 2018 Carcinogens in food additives A review In Food Safety in Developing Countries Springer Available at: https://link.springer.com/chapter/10.1007/978-981-13-3259-3_7 ↩︎
Lock EA et al. 2012 Oxidative stress induced by potassium bromate exposure results in alterations of tight junction proteins in rat kidneys Archives of Toxicology 86(2) 143-152 Available at: https://link.springer.com/article/10.1007/s00204-012-0897-0 ↩︎
Center for Research on Ingredient Safety 2021 Trending Potassium Bromate Available at: https://www.canr.msu.edu/news/potassium-bromate ↩︎
US Right to Know 2023 Potassium bromate a food additive with serious health risks Available at: https://usrtk.org/chemicals/potassium-bromate/ ↩︎
Ncheuveu NT Fon TP Navti LK 2022 Health Risk Assessment and Symptoms of Potassium Bromate Toxicity Amongst Bakers in Bamenda North West Region of Cameroon Heliyon Available at: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4005103 ↩︎

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