It’s pretty much an American tradition that the FDA only bans a controversial ingredient after companies have mostly stopped using it—that’s how it went with trans fats and with BPA in baby bottles. Now, brominated vegetable oil (BVO) stands ready to join the list. The additive was once used in Mountain Dew, and is still used in some brands of citrus-flavored sodas.
The FDA announced Thursday that it would like to revoke the regulation that declares BVO to be safe in small quantities. Currently, BVO may be used in a concentration of 15 ppm or less, “pending the outcome of additional toxicological studies” the agency is supposed to review periodically. It sounds like those reviews have finally managed to change some minds.
What is BVO, anyway?
Brominated vegetable oil is an emulsifier used in sodas that are flavored with citrus oil. Without an emulsifier, the oil would separate out, potentially forming a film or ring at the top of the drink since it is lighter than water.
BVO is called “brominated” because the element bromine is added to the oil molecules. This makes the oil heavier, so it does not float, and helps the droplets (of mixed BVO and flavoring oils) to stay suspended in the mixture.
If you’ve heard that BVO is also used as a flame retardant, that’s not exactly true; there are brominated compounds used for that purpose, but the BVO in beverages is not the same formulation.
Why is it being banned now?
There have been safety concerns about BVO for decades, but not enough studies had been done to settle the question. In 1970, the FDA decided that they could no longer include it in the “generally recognized as safe” list; in 1977, food manufacturers talked the FDA into allowing it again at much smaller doses. (It had originally been allowed at a concentration of 150 ppm; since 1977 the limit has been 15 ppm.)
Several countries, including Australia, Japan, and members of the European Union, do not allow BVO in foods or beverages at all. Manufacturers have other ingredients they can use in place of BVO, including sucrose acetate isobutyrate (SAIB), glycerol ester of rosin (also called ester gum), and locust bean gum, which are all legal under FDA rules.
In 2014 the FDA decided they still didn’t have enough information to say whether BVO is truly safe enough to stay on the market, and so they commissioned studies in rats to address some of the unresolved questions. Those studies, the FDA now says, “do not support [the] safety of BVO used as a food ingredient.”
What’s wrong with BVO?
For one thing, bromine is chemically similar to iodine, and our bodies use iodine to make thyroid hormones. Researchers have been concerned that our thyroids may be picking up bromine in place of iodine, leading to thyroid problems. The new FDA-commissioned studies found that large doses of BVO do seem to cause thyroid toxicity in rats, confirming the findings of previous studies in rats and pigs.
Another concern is that our bodies may accumulate bromine from BVO over time. The recent FDA studies confirmed this as well. This is a problem, not just because the bromine may be toxic, but also because accumulation makes it hard to do safety studies on BVO. Even if you are giving a person a specific amount of bromine for a study, you don’t know how much is actually in their bodies.
There are still plenty of questions remaining. Does BVO actually cause thyroid toxicity at the doses people encounter in orange soda? We don’t know. It might not. We also don’t know if there are issues with BVO affecting other body parts or processes. But the FDA says that now that it’s seen the evidence on thyroid toxicity and bioaccumulation, it’s not interested in spending any more time on safety studies:
While safety questions remain regarding the potential for developmental and reproductive toxicity resulting from dietary exposure to BVO, we do not believe that addressing these remaining unresolved safety questions is needed to conclude that there is no longer a reasonable certainty of no harm from this use. Therefore, we propose to revoke the interim authorization of BVO as a food additive.
In other words, BVO was allowed because it was assumed to pose “no harm” to consumers. The FDA hasn’t said that it is harmful, just that it is going to stop assuming BVO is harmless. That’s enough to get it pulled from the market.
Which sodas contain BVO?
Pepsi and Coca-Cola both said in 2014 they would no longer use BVO in their drinks, and if you check the labels on Mountain Dew (made by Pepsi) or other big name-brand sodas, you aren’t likely to see it.
But the additive is still used in Sun Drop citrus soda, Giant’s store brand orange soda, and Walmart’s store brand version of Mountain Dew, Great Value Mountain Lightning, to name a few. If a soda contains BVO, it will have “brominated vegetable oil” on the ingredients label (usually toward the end of the list, since it’s present in such small amounts).
When will the rule take effect?
The FDA has proposed a rule that would ban the ingredient, and they are taking public comment on this proposal between now and January 17, 2024. There’s no official timeline yet for when the final version of the rule will be published.
Once the final rule is published, it’s considered to be “effective” 30 days later, and manufacturers will get a one-year deadline to stop selling products that contain BVO. So we’re looking at early 2025 at the earliest if a ban takes effect.