Why is a sunscreen ingredient in my frozen pizza? (2024)

The ingredient helps block the sun’s rays when we slather it on our skin at the beach. Food makers use it to brighten up colors—think whiter mozzarella on your frozen pizza or more vibrant hues in your Skittles. Some research, mainly in animals, has suggested that eating it might be linked to immune system problems, inflammation and DNA damage that could lead to cancer.

The European Union has banned titanium dioxide in food since 2022. Earlier this year, legislators in California introduced a bill to bar foods with titanium dioxide from being served in public schools. Some public-health advocacy groups have petitioned the U.S. Food and Drug Administration to not allow it to be used in foods.

What’s tricky: It isn’t always easy to tell whether titanium dioxide is in your food. Manufacturers don’t have to list it by name on packages—it might be identified on a label only as “artificial color." But some do disclose it. And some food makers are reformulating products to remove titanium dioxide as questions about it grow.

The science isn’t conclusive. Some studies haven’t shown negative health effects, and some countries, including Canada, Australia and New Zealand, have recently reviewed the research and said that titanium dioxide in food is safe.

The Consumer Brands Association, a trade group that includes many food makers, says titanium dioxide is used safely in certain foods as a coloring, noting that the industry adheres to the FDA’s safety standards. Mars, which makes Skittles, says all of the ingredients it uses are safe.

Why titanium dioxide is in your food

In general, manufacturers add titanium dioxide to make products look more appealing. “A very small concentration makes something look very white and bright," said David Julian McClements, a professor in the food-science department at the University of Massachusetts Amherst. Adding it with other colors can make those colors pop, he said.

Titanium dioxide is most prevalent in candy, coffee creamers and frosted or powdered baked goods, said Kelsey Mangano, associate professor and nutrition program director at the University of Massachusetts Lowell. The substance is also in many chewing gums and mints.

It is a common ingredient in sunscreen because it is effective at blocking ultraviolet rays. It is used in medications for a similar reason: to help protect the active ingredients inside the pill from being broken down or altered by light.

You don’t need to worry about it in sunscreen because there isn’t evidence that titanium dioxide penetrates the skin, said Nicolaj S. Bischoff, a Ph.D. student at Maastricht University Medical Center in the Netherlands who has researched the possible health effects of titanium dioxide. And since the substance performs an important function in medications, the risk/benefit calculus is different than with food, he noted.

What the science says

New higher-resolution microscopes and other methods of detecting and analyzing particles are allowing researchers to better understand titanium dioxide.

Scientists now know that most titanium dioxide ingredients used in food contain varying amounts of tiny nanoparticles. The problem with nanoparticles is that, because of their small size, there is the potential for them to penetrate the mucous layer in your gastrointestinal tract, get into your cells and accumulate in your organs, said McClements.

Some studies in animals found that consumption of titanium-dioxide nanoparticles led to damage to the liver, immune and reproductive systems, as well as DNA. Other research has found that titanium dioxide changes the gut microbiome and inhibits the growth of beneficial bacteria.

New research in people has found a link between titanium dioxide consumption and inflammation in the gut. In a small study with 35 healthy adults, those who had the highest levels of titanium dioxide in their stool had higher levels of certain gut-inflammation measures than those with the lowest titanium-dioxide levels. They also had indications of more gut permeability, or how “leaky or separated the cells are," said Mangano, lead scientist of the study, which was published in February in the journal NanoImpact.

The concern is that chronic increased gut inflammation and permeability could increase the risk of colon cancer, nutrient deficiencies and the low-grade inflammation that underlies many chronic diseases, Mangano said. After conducting this research, Mangano said she stopped chewing gum, which often contains titanium dioxide.

Children likely face greater potential risks from titanium dioxide, said McClements. They tend to eat more foods that contain it, like candy and other sweets, and they are smaller.

The science isn’t clear-cut. Some studies in animals haven’t shown toxic effects. Scientists also disagree about which studies are relevant to how people consume it. Before the EU banned it in food, food-safety experts identified that titanium dioxide had the potential to cause damage to DNA. But they were uncertain about how exactly it happens and at what dose the damage starts to occur. So they could no longer consider titanium dioxide safe when used in food.

The occasional cupcake or creamer with titanium dioxide likely isn’t a problem, said Bischoff. The potential risks are longer term and likely from chronic exposure, he said.

What you can do

Many products that have titanium dioxide include it on the ingredient list. And there are many versions of foods that don’t contain it—including foods that aren’t packaged or ultra-processed, such as fresh fruit and vegetables.

Be aware, though, that the FDA doesn’t require food manufacturers to list the name titanium dioxide among a product’s ingredients. Companies can cite the more general “artificial color" or “artificial coloring" instead. You can contact the manufacturer to seek more detail if “artificial color" is listed on the label, an FDA spokesperson suggests.

Or you could save yourself the trouble and avoid foods with artificial colors.

Some food companies are removing titanium dioxide from certain products. Whole Foods recently reformulated its 365 brand macaroni and cheese: Its new product no longer contains titanium dioxide. Beyond Meat did the same with its plant-based chicken nuggets.

Write to Andrea Petersen at andrea.petersen@wsj.com