Brominated Vegetable Oil vs Dimethylpolysiloxane: which is worse?

What is Brominated Vegetable Oil?

Brominated vegetable oil (BVO) is a food additive created by bonding bromine atoms to vegetable oil (typically soybean oil), creating a denser-than-water compound. When added to citrus-flavored beverages, BVO acts as an emulsifier and weighting agent, keeping citrus flavor oils evenly distributed throughout the drink rather than floating to the surface.

What is Dimethylpolysiloxane?

Dimethylpolysiloxane (PDMS, polydimethylsiloxane) is a silicone-based polymer used as an antifoaming agent in food and beverages. It prevents the formation of foam during food manufacturing and cooking. It is the same base material used in silicone cookware, medical devices, and contact lenses.

Documented risks

Brominated Vegetable Oil: BVO's health concerns center on bromine accumulation in body fat and tissues. Bromine is a halogen related to iodine, and it competes with iodine in the body, potentially disrupting thyroid function—a critical concern since iodine is essential for thyroid hormone synthesis. The FDA-NIH collaborative research directly triggering the 2024 ban found adverse cardiac and thyroid effects in animal studies. This FDA-NIH work, published around 2022–2023, showed effects at dose levels closer to realistic human exposure than previous studies, removing the basis for BVO's safety determination under the Federal Food, Drug, and Cosmetic Act's 'reasonable certainty of no harm' standard. Historical case reports of human toxicity from excessive BVO consumption document bromoderma (skin lesions), memory loss, nerve damage, tremors, and fatigue in individuals consuming large volumes of BVO-containing beverages daily. Two well-documented US cases from the 1970s and 1980s involved bromism (bromine toxicity) from chronic overconsumption. Bromine bioaccumulates in fatty tissues. Long-term sub-clinical accumulation was a concern even before the FDA ban, particularly for heavy consumers of citrus sodas. The EU, Japan, and other countries banned BVO decades ago, making the US one of the last major markets to revoke approval. The FDA issued a proposed rule in November 2023 and a final rule on July 3, 2024, effective August 2, 2024, with compliance deadline August 2, 2025, after which BVO-containing products may not be manufactured for US sale.

Dimethylpolysiloxane: Dimethylpolysiloxane is generally considered non-toxic. It is not absorbed by the gut and passes through the digestive system unchanged. The FDA permits it at up to 10 ppm in cooking oils. EFSA's evaluation found no evidence of toxicity at permitted food use levels. There are no established cancer or reproductive toxicity concerns with PDMS at food use concentrations. The compound is the same base polymer used in many safe medical applications including contact lenses and breast implants (though the medical grade is different purity). The main environmental concern is PDMS persistence in the environment, as it is not readily biodegradable. Primary consumer concern is psychological rather than toxicological: the fact that it is used in both McDonald's frying oil and Silly Putty (which also contains PDMS) generates public attention, but the chemistries are actually different grades of the same polymer family.