What Is Titanium Dioxide—And Do You Really Have to Worry About It in Your Food?

Skittles has been making headlines in recent weeks and not because a new flavor has been added to the popular "taste the rainbow" candy.

Mars Wrigley, the company that makes Skittles, is being sued by a California man who claims the candy contains a "known toxin" that poses such a serious health risk that Skittles are "unfit for human consumption." 

In response to the allegations, Justin Comes, vice president of research and development at Mars Wrigley North America, told Health that "safety is of paramount importance to Mars Wrigley. While we do not comment on pending litigation, all Mars Wrigley ingredients are safe and manufactured in compliance with strict quality and safety requirements established by food safety regulators, including the FDA."

So, what does it all mean for us? Should we stop eating Skittles or begin checking foods for the presence of titanium dioxide? Here's a closer look.

What Is Titanium Dioxide?

An inorganic chemical, titanium dioxide is used as a dye to help products achieve a certain appearance, including whitening a product. Some experts and publications have described it as being akin to a "paint primer" that's used before the color is added to food in order to give products a uniform shine. Its presence is common in many items beyond Skittles including coffee creamers, cake mixes, and chewing gum. It's also used for pigment and in cosmetics manufacturing.

"Titanium dioxide particles help light scatter and reflect," Kelly Johnson-Arbor, MD, a medical toxicology physician at the National Capital Poison Center, told Health. "Because of that, we often use it as a whitening agent."

While Skittles don't include white in their line-up, Dr. Johnson-Arbor theorizes that titanium dioxide is used to help contain all the other beautiful colors.

Other food manufacturers use titanium dioxide to absorb water and keep moisture from clumping or degrading, Paul Westerhoff, PhD, an environmental engineer at Arizona State University who researches the biological and cellular effects of titanium dioxide, told Health.

The chemical is also found in common household and industrial products such as paints, coatings, adhesives, paper, plastics and rubber, printing inks, coated fabrics and textiles, as well as ceramics.

It's also used in sunscreens as a UV filtering ingredient, helping to protect a person's skin by blocking absorption the ultraviolet light that can cause sunburn and cancer.

"It's all over the place in our environment," said Dr. Johnson-Arbor.

Does It Cause Cancer?

Concerns that titanium dioxide may cause cancer stem from a 1985 study that exposed rats to high doses of titanium dioxide over a two-year period, causing them to develop lung cancer. However, many experts are skeptical of the study's conclusions. Professor Norbert Kaminski of Michigan State University noted that the doses these rats were exposed to were much higher than humans are actually exposed to. A 2006 study by the International Agency for Research on Cancer also said that the evidence was insufficient to prove that titanium dioxide causes cancer, but listed it as a potential human carcinogen. Although some animal studies have shown that titanium dioxide is associated with cancer, such as a 2017 study that found that rats that ingested titanium dioxide had impaired immune systems, many experts believe that existing research is insufficient to support these health concerns. A 2022 review study noted that the original study was conducted under extreme conditions and its results were not replicated in other animal species. In addition, the few studies that directly studied the effects of titanium dioxide on humans did not show an increased risk of cancer. Overall, the risks of titanium dioxide are low compared to other potential health risks.