A Slice of Crazy: EWG Thinks Frozen Pizza May Cause Cancer

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If you're worried about Monkeypox, school shootings, car accidents, or any other possible threat to your health, stop this instant. The Environmental Working Group (EWG) has identified a greater risk for you to fret about—frozen pizza.

If you're like me, you've eaten a fair amount of frozen pizza throughout your life and experienced few or no side effects. That's because this classic American cuisine carries no serious health risks. Provided you don't eat inordinate amounts of it, pizza is a perfectly fine meal choice. But it won't surprise regular ACSH readers to learn that our friends at EWG don't share my affinity for pizza rolls. “A slice of health problems: Frozen pizza chemicals linked to cancer, DNA and immune harms,” the activist group announced to its supporters in a July 29 blog post:

Although almost everyone has had this popular food item in their freezer at one point, some brands might be serving up chemical ingredients that have the potential to cause health harms ... [A]lways read the frozen pizza box to avoid potentially harmful ingredients and additives.

It's generally a good idea to know what you're eating. Consuming a balanced diet and managing your caloric intake are reasonable nutritional recommendations. But should you read the labels because the foods they adorn are loaded with carcinogenic chemicals? You know the answer. Let's take a closer at one of the chemicals EWG is crying crocodile tears over and how the Food and Drug Administration (FDA) regulates it.

Titanium dioxide, a color additive that may cause damage to DNA, can be found in frozen pizzas …

This chemical (which also goes by "TiO2") is widely used in consumer products and foods. It's added to mozzarella cheese, for example, to enhance its white color. Cutting certain brands of frozen pizza out of your diet won't make a dent in your exposure. But don't start frantically googling ingredient lists. The FDA has determined that titanium dioxide can be used safely in everything from toothpaste to baked goods.

The European Food Safety Authority (EFSA) agrees that titanium dioxide poses minimal risk. That regulatory agency evaluated the available data in 2019, finding that rats fed 2,250 mg of titanium dioxide per kg of body weight per day – a huge dose – experienced no adverse effects. My colleague Dr. Chuck Dinerstein added that a package of Skittles weighs 61.5 grams. Pointing to this 2015 paper, he noted that candy in the US contains an average of 33 mg of artificial food coloring. You'd have to eat 68 bags of skittles daily to reach the EFSA's 2,250 mg figure—and your stomach would explode long before TiO2 gave you cancer. 

Among other observations, EFSA also reported that “the absorption of orally administered titanium dioxide is extremely low" and “the vast majority of an oral dose of titanium dioxide is eliminated unchanged in the faeces.” In other words, it goes in, doesn't cause cancer, then it goes out.

Gaps in the data?

It's possible that these animal models don't adequately capture titanium dioxide's effects on the human body “due to knowledge gaps as to local gastrointestinal effects of TiO2 particles,” as one 2018 analysis pointed out. The authors therefore argued that existing toxicological data "cannot completely exclude human health risks from the long-term ingestion of TiO2 particles" and called for more studies to be done.

We'll never "completely exclude" any health risk. It's just not possible to show that a chemical will never have a negative effect. Still, fair enough; I understand the qualification the reviewers have put forward. Perhaps better studies should be done, but I hasten to add that this cuts both ways. If animal models can't vindicate the use of TiO2 as a food additive, then animals that develop tumors after prolonged exposure to very high doses can't be used to scare consumers.

Human studies offer reassurance

The good news is that we have some decent data on human exposure. Consider the results of this 2004 review from the International Agency for Research on Cancer (IARC), which once tried to tell everyone that drinking coffee may cause cancer. If any group of scientists would find evidence of titanium dioxide's carcinogenicity, it's IARC. The WHO sub-agency is so paranoid that even EWG accepts its determinations. That's an interesting factoid because IARC reviewed the cancer risk of 15,017 workers employed by 11 factories producing TiO2 in Europe. Guess what they found:

[M]ortality from lung cancer did not increase with duration of employment or estimated cumulative exposure to TiO2 dust … The results of the study do not suggest a carcinogenic effect of TiO2 dust on the human lung.

Men in the study had slightly higher rates of lung-cancer-associated mortality. But they were also more likely to smoke, which the authors identified as the probable cause of their higher mortality rates. IARC published a monograph in 2010 which classified titanium dioxide as possibly carcinogenic to humans based on animal studies, though it added that "There is inadequate evidence in humans for the carcinogenicity of titanium dioxide."

But, wait, there's more. According to a 2019 review, eight studies have evaluated the health effects TiO2 exposure in industrial workers. “Results suggested possible pulmonary and cardiovascular effects,” the authors acknowledged. “Nevertheless, no causal link between TiO2 inhalation exposure and the observed effects could be established in these studies.”

Parenthetically, these individuals had dramatically higher exposure to TiO2 than the average American pizza eater. Dietary intake of titanium dioxide in the US is quite low, an estimated 1–2 mg/kg body weight per day for children under 10 years old and 0.2–0.7 mg/kg/day for the rest of the population. If these factory employees didn't suffer any serious adverse effects from their occupational exposure, then none of us have either— considering our far lower exposures.


Let's wrap up with a look at the FDA's regulation of food additives. According to EWG:

These chemical additives, and many others, get into the food we eat through legal loopholes that allow food and chemical companies, not the Food and Drug Administration, to decide they’re safe for human consumption.

This claim sounds less ominous with the data we just discussed in mind. However, it's still worth pointing out that you can debunk EWG's claims often by just reading the FDA's website. The agency only allows the use of titanium dioxide in food if “The quantity ... does not exceed 1 percent by weight of the food.” Far from beholden to its corporate overlords, here's what FDA actually says about its regulatory authority over food additives:

Food and color additives are strictly studied, regulated and monitored. Federal regulations require evidence that each substance is safe at its intended level of use before it may be added to foods. Furthermore, all additives are subject to ongoing safety review as scientific understanding and methods of testing continue to improve. Consumers should feel safe about the foods they eat.

And with that, I'm off to lunch. Frozen pizza seems like an appropriate choice.