Titanium dioxide

Studies in people

• Open question

  Body tissue buildup²

  Titanium dioxide particles were found in liver, spleen, kidney and gut tissue of 15 deceased people.

Animal and lab studies only

• Concern

  Gut inflammation and cancer¹²

  In animal studies, daily intake of titanium dioxide was linked to a higher risk of gut inflammation and cancer.

• Open question

  Gut health effects¹³

  In lab studies, it is unclear whether titanium dioxide can damage DNA in the gut.

• Open question

  Gut immune cells¹⁴

  In animal studies, titanium dioxide builds up in small-intestine immune cells but did not trigger inflammation on its own.

• Open question

  DNA damage from food additives¹⁵

  In lab studies, titanium dioxide did not directly damage DNA; positive results came only with cell stress.

• Concern

  Gut inflammation and cell damage¹⁶

  In lab studies, pretreated titanium dioxide harmed Caco-2 cells, but this did not happen with butyrate present.

• Concern

  DNA damage in gut cells¹⁷

  In lab studies, titanium dioxide harmed DNA in gut cells, but albumin or blood serum lowered that harm.

Study type not stated

• Open question

  Gut and immune effects⁵

  Scientists do not yet know whether eating titanium dioxide, a whitener in food, causes gut or immune problems over time.

• Open question

  Unknown cell effects⁶

  Scientists do not yet fully know how titanium dioxide particles affect cells.

• Concern

  Uncertain study findings⁷

  Scientists looked at titanium dioxide in food and said the studies raised concerns but were too uncertain to settle the question.

• Open question

  Cancer risk in people⁸

  Recent studies question whether titanium dioxide's surface changes affect its reactivity, and its cancer risk in people is still disputed.

• Concern

  Particle buildup in brain¹⁰

  Titanium dioxide tiny particles can pass into the brain and may build up in tissue over time.

• Concern

  DNA damage risk¹¹

  Some regulators say titanium dioxide in food may damage DNA, while others say there is not enough evidence.

Found in some samples or products

These come from where it was grown, how it was processed or cooked, or what it was made into. They are not about the ingredient itself, so the signal does not count them.

• Milk contamination⁴

  Titanium dioxide particles turned up in human, animal and baby formula milk samples, so newborns may be exposed daily.

How it’s made and used

• How much the body absorbs³

  How much titanium dioxide people ate did not match how much came out in their stool.

• How much is in food⁹

  Titanium dioxide was found in sweets, gum and chocolates, but labels do not say how much is used.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.

Expert panels that weigh all the research. Shown for context: the signal at the top does not count them. IARC rates whether something can cause cancer at all, not how likely it is at the amounts in food.

• UN and WHO food additive experts (JECFA), 2023

  No daily limit needed (“ADI not specified”, JECFA’s term for very low toxicity).

• WHO cancer agency (IARC), 2006

  Possibly causes cancer in people (Group 2B).