Food Additives, Bromine and Thyroid Disorder

Bromine is used as a food additive in flour and some fruit-flavored soft drinks. Unfortunately, bromine can have a negative impact on your thyroid gland. While the amount allowed in foods and beverages is limited by the U.S. Food and Drug Administration, it's still smart to watch for the presence of additives in the foods you purchase.


Bromine is an element that belongs to the same group as chlorine and iodine. In its pure state, bromine is a reddish-orange liquid that gives off an unpleasant odor, but in nature it combines with other substances to form a salt. In liquid or vapor form, bromine is harmful to the skin, irritates the eyes and throat and can be toxic. Bromine is used in pesticides and gasoline; as a fire retardant in fabrics, carpets, upholstery and mattresses; and as an alternative to chlorine in swimming pool treatments. Bromine is also used as a food additive.

Food Additives

Food additives are nonfood substances that improve nutritional value, maintain food quality, prevent spoilage, make food more appealing through color or flavor or make food easier to prepare. Bromine is used as an additive in the forms of potassium bromate and brominated vegetable oil. In citrus-flavored beverages, brominated vegetable oil keeps citrus flavors suspended throughout the fluid. When it's added to flour, potassium bromate strengthens bread dough, helps it rise higher and improves the texture of the finished product. As long as the proper amount of potassium bromate is used, the process of baking turns it into a harmless substance.


Bromine disrupts the thyroid gland and interferes with the production of thyroid hormones. The thyroid gland relies on iodine obtained through the foods you eat to produce thyroid hormones that are essential for normal growth, development and metabolism. Because it’s so similar to iodine, bromine can take the place of iodine, which results in less iodine for the thyroid gland. This interferes with the thyroid’s ability to function and can lead to hypothyroidism. Bromine may also increase the elimination of iodine from the body, which also lowers the amount of iodine available for the thyroid gland.

Health Warnings

In addition to potential effects on the thyroid, potassium bromate is a category 2B carcinogen, according to the International Agency for Research on Cancer 4. Class 2B means that it has caused cancer in laboratory animals, but that there is only limited evidence of its potential to cause cancer in people. It has been banned from use as a food additive in Europe and Canada. The U.S. Food and Drug Administration asked bakers to voluntarily use other additives and set limits on the amounts that can be used in baked goods and soft drinks, but did not ban the additive. The Center for Science in the Public Interest recommends cautionary consumption of brominated vegetable oil and suggests avoiding potassium bromate 5. You can easily avoid these additives by looking for “bromated flour,” “potassium bromate” or “brominated vegetable oil” in the list of ingredients.