Canadians don’t worry about potassium bromate, a possible carcinogen, in their toast because the ingredient has been banned in their country. Europeans don’t need to fret whether titanium dioxide causes DNA damage because food companies there can’t put it in their salad dressings.
Here in the United States, things are a little more complicated.
The Food and Drug Administration (FDA) takes a less aggressive approach to regulating additives, which means that many ingredients banned in other countries remain in our food supply. This is yet another reason to avoid processed—especially ultra-processed—foods.
On his list of the 11 nutritional properties that distinguish processed foods from real foods, Dr. Robert Lustig, author of Metabolical: The Lure and Lies of Processed Food, Nutrition, and Modern Medicine, separates the properties into two categories: “not enough” and “too much.” Additives fall on the side of too much, along with sugar and trans-fats, while processed foods don’t contain enough fiber or micronutrients.
Diets high in processed foods are associated with severe negative metabolic health impacts, including insulin resistance, oxidative stress, and gut microbiome imbalances, increasing the risk of chronic diseases including Type 2 diabetes, cancer, and cardiovascular disease. These outcomes may be connected to the poor nutritional makeup of processed foods, but certain additives may also pose specific health dangers.
Why Are Potentially Damaging Ingredients Allowed in Our Food System?
Some unhealthy food additives—like high-fructose corn syrup and table sugar—are unregulated and ubiquitous worldwide.
Compared to the FDA’s process for reviewing additives, systems in certain places like Europe are more “discerning,” Dr. Lustig says. There are a few reasons for that. While it’s in the FDA’s charter to guarantee the safety of our food supply, that charter mainly deals with screening for things in food that have acute toxicity, he explains in his book Metabolical. In other words, when regulators assess food safety, they’re looking to prevent immediate illness and death caused by eating foods containing things like E.coli or Salmonella. They pay less attention to chronic toxicity, where eating a food may not cause apparent damage in the short term, but cumulative exposure can lead to long-term illness and disease.
While the FDA does its own research to determine the safety of most food additives, many see its system for additives considered “GRAS”—which stands for “Generally Recognized As Safe—as a loophole. The agency allows private companies to convene their own teams of scientists to declare certain additives GRAS and then reviews the notification sent by a company. Once those additives are on the list, they’re not regulated, Dr. Lustig explains. “GRAS has simply become a back door for the food industry to add substances to our food supply without FDA approval,” he says, noting that at least 1,000 items on the GRAS list have never undergone full FDA review.
Other food additives, like the ones on the list below, have gone through FDA review to get onto the more formal approved list. But there’s a catch there, too. “A lot of [additives] were approved a long time ago, and the FDA hasn’t gone back through those chemicals to determine whether they’re still safe or not,” explains Melanie Benesh, who works on toxic chemical regulation at the Environmental Working Group (EWG). So while new studies are published each year that may change our scientific understanding of an additive’s health impacts, those are often not taken into consideration by the FDA.
What Are Some of the Worst Processed Food Ingredients to Avoid?
Most of the substances on the GRAS list or approved by the FDA as additives appear to be genuinely harmless. For others, there is significant evidence of adverse health effects.
Here are seven of the worst offenders to avoid. For most, evidence of potential harm is limited to lab and animal studies, meaning we can’t say for sure that the same impacts will occur in humans. But experts like Dr. Lustig and the scientists at the EWG say the research is strong enough to apply the “precautionary principle,” especially since the food supply contains so many additives and it’s unclear what cumulative exposure might mean over time. That principle is simple: If there is any evidence that suggests it might not be safe, it makes sense to avoid it. And in the case of these additives, other countries’ government scientists have decided that there is at least enough evidence to suggest—if not prove—harm.
The best bet: skip ultra-processed foods altogether. If you do find yourself picking up something processed, check your food labels for these ingredients banned in other countries.
Potassium Bromate and Azodicarbonamide (ADA)
Potassium bromate and azodicarbonamide are used as “dough conditioners,” ingredients added to the flour mixtures used in bread, crackers, and other baked goods that help dough rise, improve texture, or strengthen. According to the Center for Science in the Public Interest (CSPI), during baking, most potassium bromate is converted into a different compound that is safe to eat. Still, small amounts of bromate, the chemical that worries experts, remain in the food. On the flipside, azodicarbonamide isn’t dangerous to start, but during the baking process, another potentially harmful chemical called urethane can be formed.
Health concerns: Potassium bromate is listed as a carcinogen by the state of California, and the International Agency for Research on Cancer (IARC) lists it as “possibly carcinogenic” to humans, a classification that is less conclusive than “probably carcinogenic” or “carcinogenic” but still indicates concern about links to cancer. Some animal studies have shown potassium bromate causes tumors and kidney damage in rats, and lab studies suggest the additive may damage DNA. EWG includes potassium bromate on its list of the 12 worst food additives to avoid.
Less direct evidence of harm exists for azodicarbonamide, but the lack of clarity on its safety is cited by groups like CSPI as a reason to avoid it. The biggest concern is the production of ethyl carbamate (also called urethane), which IARC lists as “probably carcinogenic” during baking. That means its link to cancer is even stronger than potassium bromate’s. But an FDA study done in 1997 found that azodicarbonamide only “slightly” increased levels of ethyl carbamate when added to flour at the levels bakeries typically use, so how much you’re getting exposed to in food is unclear.
Brominated Vegetable Oil (BVO)
Emulsifiers are food additives that allow manufacturers to combine ingredients without separation occurring; brominated vegetable oil, or BVO, is one that’s used in soda. While it was an ingredient in popular soft drinks like Mountain Dew and Fanta for a long time, PepsiCo and Coca-Cola have phased it out over the past few years. But smaller brands, including Sun Drop Citrus Soda and store-brand products such as some Food Lion soft drinks, still contain it.
Health concerns: More research is underway, but recent animal studies suggest that low concentrations of certain emulsifiers may cause intestinal inflammation and metabolic syndrome, conditions linked to diseases such as Type 2 diabetes and Crohn’s disease. Why they might do this is still unclear but may be related to changes to the gut microbiome, according to researchers. It’s also unclear if the effects extend to all emulsifiers.
In the specific case of BVO, health concerns are primarily linked to the fact that it contains bromine, which can irritate skin and mucous membranes and cause neurologic symptoms like headaches and memory loss over time. However, those impacts occur when BVO is consumed in very high amounts; there have been cases of individuals who drank more than two liters of soda containing BVO a day and developed memory loss and nerve problems. Similarly, decades-old studies showed rats may develop heart lesions and reproductive issues after ingesting BVO in high doses.
While evidence of harm at low levels is still inconclusive, experts say it’s better to avoid BVO because it has the potential to accumulate in the body over time. Plus, it’s far from a necessary ingredient in our food supply.
Found in baked goods, dairy products, salad dressings, and chewing gum, titanium dioxide is an artificial color with a white pigment. It’s relatively common in processed foods, including Coolhaus ice cream pints, Little Debbie Zebra Cakes, and Skinnygirl Buttermilk Ranch Dressing.
Health concerns: In 2021, the European Food Safety Authority announced the results of a scientific review that considered thousands of studies. It concluded that while there wasn’t enough evidence to deem titanium dioxide toxic, researchers could no longer consider it safe in food because they “could not exclude genotoxicity concerns after consumption of titanium dioxide particles.” Genotoxicity refers to the ability of a substance to damage DNA within a cell, causing mutations that could lead to cancer. Researchers determined that titanium dioxide particles do have the potential to cause breaks in strands of DNA and damage to chromosomes. Still, there were not enough studies available to deduce how often those changes happen in people or if they’d be significant enough to cause health issues. So, they concluded it would be safer to avoid the ingredient until research progresses and can provide more definitive answers.
One thing that was important to their conclusion is that titanium dioxide in food is partially made up of nanoparticles, and while very little of the ingredient is added to food, the particles can accumulate in the body. A 2019 research review found the nanoparticles accumulate in places like the lungs, liver, and kidneys in animal studies and that they can have a genotoxic effect. It also found titanium dioxide particles can induce inflammation, a condition associated with multiple diseases.
Regulations: The FDA allows companies to add minimal amounts of titanium dioxide to food. While the European Union used to do the same, its ban goes into effect in mid-2022. France already banned it earlier, in 2020.
Yellow 5, Yellow 6, Red 40
As their names suggest, Yellow 5, Yellow 6, and Red 40 are food dyes, and they are used to make sugary junk food like candy, cookies, and cakes look colorful and appealing. They are also used to add color to more surprising foods, like yogurt cups, breakfast cereals, and snack packs of sunflower seeds. While many other artificial and “natural” colors are added to foods, these three are the most problematic among a group of synthetic chemicals called FD&C (Food Drugs and Cosmetic Act) colors. Skittles contain the entire rainbow.
Health concerns: While the body of research linking FD&C colors to conditions like ADHD and hyperactivity in children is still inconclusive, in 2021, scientists in the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment released the results of a 2018–2020 evaluation of the chemicals. They found that while children vary in their sensitivity, overall, “consumption of synthetic food dyes can result in hyperactivity and other neurobehavioral problems,” such as inattentiveness and restlessness. Those symptoms are often components of an ADHD diagnosis. They also determined that the limits on how much of these colors companies can add to food set by the FDA were based on old data and are no longer adequate to protect children.
In addition, a 2012 review of FD&C dyes and toxicity found that these three—Yellow 5, Yellow 6, and Red 40—have been shown to be contaminated with carcinogens in past studies. A 2010 report completed by CSPI found Yellow 5 was positive for genotoxicity—DNA damage associated with cancer risk—in six out of eleven studies reviewed by researchers.
EWG includes the entire group of FD&C colors on its Dirty Dozen list of food additives to avoid.
Regulations: Yellow 5, Yellow 6, and Red 40 are authorized for use in the European Union member states, but companies must include a warning on food labels that reads “may have an adverse effect on activity and attention in children.”
While some potentially concerning additives are allowed in the US food supply, and getting used to reading labels is important, it’s helpful to remember that a diet composed of primarily unprocessed foods is already a great way to avoid the bulk of these additives.