Bromine is an element found throughout the environment in water, soil, and air, existing primarily as the bromide ion. This trace element enters the human diet through natural absorption by organisms and deliberate commercial addition to processed foods. Understanding the sources requires distinguishing between its natural presence in whole foods and synthetic food additives.
Natural Dietary Sources of Bromine
The concentration of naturally occurring bromine in food is highly variable, depending largely on the content of the surrounding soil and water. Marine environments are particularly rich sources, meaning foods derived from the sea typically contain higher levels of bromide. Seawater contains bromide at concentrations of about 65-70 milligrams per liter, which is reflected in sea salt.
Marine fish, shellfish, and seaweeds absorb and accumulate bromide, making them concentrated dietary sources. Beyond marine life, certain plant-based foods also contribute to natural intake, including grains, nuts, and specific vegetables like bell peppers. The bromide content in these terrestrial foods is heavily influenced by soil quality and is often lower than in marine products.
Bromine’s Role in Human Health
Bromine is recognized as an essential trace element for all animals, including humans, despite lacking a specific Recommended Dietary Allowance (RDA). Its biological function was identified through research into the integrity of basement membranes, specialized sheets of the extracellular matrix underlying epithelial tissues.
Bromide acts as a required cofactor for the enzyme peroxidasin, which facilitates the formation of sulfilimine cross-links in collagen IV. These cross-links stabilize the collagen IV scaffold, providing structural support to tissues. Without sufficient bromide, this scaffolding can become compromised, demonstrated by developmental defects in animal models. Bromine is necessary for proper tissue development and maintaining the strength of internal membranes.
Brominated Compounds Added to Food
Bromine enters the diet through two primary commercial additives used in food processing. These compounds are chemically distinct from the naturally found bromide ion and have been the subject of significant public and regulatory debate.
The first is Brominated Vegetable Oil (BVO), a vegetable oil modified with bromine atoms. BVO was historically used as an emulsifier in citrus-flavored beverages, such as some soft drinks, to prevent the flavor oils from separating and floating to the surface. While the U.S. Food and Drug Administration (FDA) previously allowed its restricted use, the agency finalized a rule in 2024 to revoke its authorization for use in food, citing potential adverse health effects. BVO has been banned in the European Union, India, and Japan for years.
The second common additive is potassium bromate, which functions as a dough conditioner or flour enhancer in baked goods. It is a powerful oxidizing agent that strengthens the dough and allows for higher rising and a whiter finished product. When used correctly, the baking process should convert the potassium bromate into non-harmful potassium bromide, but measurable residual amounts can remain. The International Agency for Research on Cancer (IARC) classifies potassium bromate as a possible human carcinogen. It is banned in many countries worldwide, but remains allowed, though discouraged, by the FDA. California became the first U.S. state to enact a ban on its sale starting in 2027.
Understanding Bromine Intake and Safety
The human body’s daily intake of bromine from natural food and water sources is typically low, estimated to be a few milligrams, and is considered safe. The body handles inorganic bromide ions similarly to chloride ions, the main negative ion in the body. Bromide is excreted primarily through the kidneys, which can be a slow process because it competes with chloride for reabsorption in the renal tubules.
Problems arise from chronic, excessive exposure, which can lead to a toxic condition called Bromism. Bromism is characterized by the accumulation of bromide in the body, causing neuropsychiatric and neurological symptoms, including confusion, memory impairment, and psychosis. Historically, this condition was linked to bromide-containing sedatives, but today it is rare. The acceptable daily intake (ADI) for inorganic bromide is set at up to 0.4 milligrams per kilogram of body weight per day.