Soda additive linked to thyroid toxicity may finally get banned by FDA

The Food and Drug Administration may finally ban a food additive used in citrusy drinks that the agency determined over 50 years ago could not be considered generally safe. The agency proposed a ban on the additive Thursday.

The additive is brominated vegetable oil (BVO), which is a flavoring emulsifier and stabilizer that has been used to keep citrus flavoring from separating and floating to the top of soft drinks since the 1920s. It was previously used in big brand-name beverages such as Mountain Dew and Gatorade but has been removed amid toxicity concerns in recent years. Since at least 2014, PepsiCo and Coca-Cola have been phasing out BVO from their drinks, though it can still be found in some store-brand sodas and regional drinks, including the citrus soda Sun Drop.

BVO is already banned in Europe, Japan, Australia, and New Zealand. In October of this year, California banned BVO, along with other problematic food additives, including red dye No. 3. (While reporting California's ban on red dye No. 3, Ars also reported that the FDA planned to ban BVO.)

The FDA's proposed ban on BVO is a long time coming. Toxicity concerns have dogged BVO for over 50 years. The brominated oil accumulates in fat, the liver, heart, and brain over time, and there are long-standing concerns of thyroid toxicity, developmental neurotoxicity, and reproductive toxicity.

In January 1970, the FDA revoked BVO's status as GRAS, or "Generally Recognized As Safe." At that time, manufacturers were using BVO at a level of up to 150 parts per million (ppm) in beverages. In response, the additive industry petitioned the FDA to keep allowing the use of BVO, but at a lower limit of 15 ppm. The FDA was still not convinced it was safe and called for additional long-term safety studies. But, it didn't outright reject the request—instead, the agency allowed the use of BVO at the lower limit while the safety studies were being conducted, citing "an adequate margin of safety" at the reduced level.

Not so fast or nimble

At first, the authorization to use BVO at 15 ppm was only on an interim basis—a three-year term as the agency awaited more data. But, in 1974, still waiting for more data, the interim basis became an "indefinite period," which is ongoing.

In a 2014 review of BVO, the FDA recognized the "unresolved safety questions" and designed rodent studies to address them, which were eventually run by the National Center for Toxicological Research (NCTR). While neurotoxicity and reproductive toxicity were among the lingering questions, the NCTR studies only looked at bioaccumulation and thyroid toxicity, noting that if these showed toxicity, it would be enough to revoke the authorization of BVO. The studies did show toxicity.

The rat experiments, published in 2022, used levels of BVO that mimicked dietary exposure of humans at the 15 ppm limit. In feeding trials, researchers found abnormalities in the rats' thyroids, alterations in their hormone signaling, and accumulation of brominated fatty acids in the heart, liver, and fat of all animals fed BVO.

"[W]e can no longer conclude that there is a reasonable certainty of no harm from the use of BVO as a stabilizer for flavoring oils in fruit-flavored beverages," the FDA said in its proposal to revoke authorization.

In a separate statement, James Jones, the FDA's Deputy Commissioner for Human Foods, noted that these types of safety reviews take time, but seemed to acknowledge the agency's extremely slow process. He pointed to a proposed internal restructuring at the FDA that will "include the creation of the Office of Food Chemical Safety, Dietary Supplements and Innovation where we intend to develop a faster and more nimble process for evaluating chemicals in the food supply."

Jones also noted that the FDA is currently reviewing red dye No. 3, and a decision on potentially banning that additive—as was already done in California —is "forthcoming."