Center for Research on Ingredient Safety

What is titanium dioxide? What does titanium dioxide do?

Titanium dioxide is a white, powdery substance that is widely used as a pigment, brightening agent, and protectant in various food, cosmetics, pharmaceuticals, and other industrial uses.

It is a naturally occurring oxide of the metal titanium. Titanium dioxide forms when titanium is exposed to oxygen, creating many differing titanium oxides found in minerals, dusts, sands, and soils.

Titanium dioxide added to foods and other ingestible products is commonly known as E 171, indicating its high food-grade purity.

Titanium dioxide amplifies and brightens white opacity because of its exceptional light-scattering properties. In food and drugs, these properties help to define colors clearly and can prevent products from UV degradation.

In cosmetics, titanium dioxide's properties enhance coloration and can help protect skin from damaging UVA and UVB rays.

How are we exposed to titanium dioxide?

There are three main ways we are exposed to titanium dioxide: 

• Digestive system: We're primarily exposed to E 171 through the foods we ingest and the medications we take. 

• Integumentary system (e.g., skin): We apply titanium dioxide to our skin through sunscreens, makeup, lip balms, nail polish, and other cosmetic products.

• Respiratory system: In industrial settings, people can be exposed to titanium dioxide through inhalation. Inhalation exposure to titanium dioxide is exceedingly rare for most people.
   

Why do many researchers and regulatory agencies agree titanium dioxide is safe?

In 1979, researchers conducted an in-depth, foundational study in animals that looked at lifelong exposure to titanium dioxide, up to very high doses (approximately 5% of their diet). The study followed the animals through their entire life cycle of two years to observe any adverse health impacts. 

Researchers did not find any adverse health effects due to titanium dioxide consumption via food, including the occurrence of cancer. 

Studies like the above-mentioned foundational study are still considered the best-in-class because they look at chronic exposure over a lifetime which more completely characterizes the potential health impacts, as you can observe potential toxicities throughout all stages of life. 

Additionally, many studies published in the scientific literature administered titanium dioxide to research animals in irrelevant ways, like through drinking water rather than in their diet (1,2).

Are nanosized titanium dioxide particulates harmful?

Some regulatory organizations have raised concerns about the size of titanium dioxide particles found in food products. They worry because some particles can be smaller than 100 nanometers in diameter, which is considered "nano" size. However, it's important to note that most of these particles in food are larger, typically in the micron diameter range (1,000 nanometers).

Particles smaller than 100 nanometers tend to clump together or agglomerate when present in water or digestive fluids. As a result, their ability to pass through biological barriers becomes extremely limited. Similarly, particles larger than 100 nanometers struggle to move across these barriers because they are too big.

How do Western regulatory agencies view titanium dioxide?

Every country has its own processes to ensure food safety; in this post, we're looking at the Western regulatory agencies, although we anticipate additional safety reports from the rest of the developed countries soon.  

• U.S. Food and Drug Administration: Maintains Safety 

• Food Standards Australia and New Zealand: Maintains safety

• Health Canada: Maintains Safety 

• Food Standards Agency U.K.: Maintains safety (interim opinion), conducting a risk assessment

• European Food Safety Authority (participant countries): Banned

Why has the European Union's Food Safety Authority banned titanium dioxide in food? Is it harmful to our health?  

Overwhelmingly, research relevant to human exposure shows us that E171 is safe when ingested normally through foods and medications (1,2).

While some data suggest that E 171 could cause harm, those research processes did not design their studies to model how people are exposed to E 171. Research that adds E 171 to drinking water, utilizes direct injections, or gives research animals E 171 through a feeding apparatus does not replicate typical human exposure, which occurs through food and medicine consumption.

Read more in-depth about the titanium dioxide risk at go.msu.edu/8Dp5. 

Didn't the European Union change its regulatory stance on titanium dioxide recently?

On November 23, 2022, the General Court of the European Union reversed the conclusion that inhaled titanium dioxide was carcinogenic and released a statement (1,2):

"First, the Commission made a manifest error in its assessment of the reliability and acceptability of the study on which the classification was based and, second; it infringed the criterion according to which that classification can relate only to a substance that has the intrinsic property to cause cancer."

 As part of our mission at CRIS, we base our safety assessments on the currently available scientific evidence and consider many variables (e.g., study quality, journal of publication, etc.), even if it goes against previous conclusions. Evidence-informed decisions making is critical to ensure that the laws and regulations put into place are for the benefit of the population.

  The E.U. General Court maintains that the scientific evidence presented wasn't the complete picture of the ingredient, "in the present case, the requirement to base the classification of a carcinogenic substance on reliable and acceptable studies was not satisfied."

What does this court ruling mean for E.U. regulation?

While this ruling from the E.U. General Court doesn't immediately change the regulations surrounding titanium dioxide, nor does it change the ban that went into place in 2022, it does put the ingredient back in the spotlight.

In the coming months, we will see how the ruling impacts the regulations around titanium dioxide, and we'll see if the European Food Safety Authority (EFSA) will take another look at the body of scientific evidence used to justify the current ban on E 171 in foods and pharmaceuticals.

The good news.

Overwhelmingly, regulatory agencies agree that food-grade titanium dioxide is safe to consume in quantities as currently allowed. That said, we will see what the future holds for food-grade titanium dioxide.

If you have any questions about foods and ingredients, please reach out to us on Twitter, send us an email, or submit your idea to us at go.msu.edu/cris-idea