Cookies on Nutrition and Food Sciences

Like most websites we use cookies. This is to ensure that we give you the best experience possible.

Continuing to use www.cabi.org means you agree to our use of cookies. If you would like to, you can learn more about the cookies we use.

News Article

Titanium dioxide: growing concerns for its safety in food


Evidence is growing that nanoparticles in the additive may be causing harm.

A recent study by scientists at Binghampton University has added to concerns that nanoparticles of the food additive titanium dioxide could be hazardous to human health. It suggests that nanoparticles of titanium dioxide (TiO2) may be affecting the ability of intestinal cells to absorb nutrients as well as causing inflammation. Together with a recent study that suggests nanoparticles of TiO2 may be involved in carcinogenesis, and studies that show the particles can reach internal organs, this study raises some safety concerns. Research is needed to see if these findings are replicated in humans.

Food sources and safety

We consume TiO2 daily in many processed foods. It is commonly used as a whitening and brightening agent. It helps to extend shelf–life, enhances colours and has protective UV qualities, all of which make it desirable to the food industry. It is most commonly found in confectionery, cakes, milk, and chewing gum. Worryingly, children appear to consume most TiO2 (Weir et al. 2012).

TiO2, was first approved by the Food & Drug Administration for use in food in 1966, and is considered safe by many countries. EFSA reviewed its safety as a food additive in 2016.

This study

In this study Professor Mahler at Binghampton University and her team used an in vitro model, to expose epithelial small intestine tissue to physiologically relevant doses of nano sized titanium oxide (30 nm TiO2) for either 4 hours or 5 days. They found a significant decrease in the number and effectiveness of the absorptive microvilli in the cells that had been exposed to TiO2 for 5 days and impairments in transport of iron, fatty acids and, zinc. They concluded that TiO2 nanoparticle ingestion may affect the functioning of the intestines.

“There has been previous work on how nanoparticles affects microvilli, but we are looking at much lower concentrations,” said Professor Mahler, “We also extended previous work to show that these nanoparticles alter intestinal function.”

Size matters

These results are relevant to food grade TiO2. This type of TiO2 is not classed as a nanomaterial but scientists have estimated that 10-40% of it is nanoparticles. Nano-sized particles of TiO2 are of concern because they aresmall enough to cross the body’s protective gastro-intestinal tract barrier and reach internal organs.

The Binghampton University study comes just after one published by Bettini et al, in January 2017 that found disturbing abnormalities in rats taking an oral dose of human-relevant levels (10 mg/kg of BW/day) of food grade TiO2 for 100 days. The titanium dioxide promoted colon inflammation and precancerous lesions.

Bettini et al. say their findings justify further studies of carcinogenic effects of TiO2 and it is reported that the French government has ordered an enquiry into TiO2 safety in foods.

Reference

Titanium dioxide nanoparticle ingestion alters nutrient absorption in an in vitro model of the small intestine. Zhongyuan Guo, Nicole J. Martucci, Fabiola Moreno-Olivas, Elad Tako, Gretchen J. Mahler, NanoImpact Volume 5, January 2017, Pages 70–82. http://dx.doi.org/10.1016/j.impact.2017.01.002

Binghampton University press release

 

Article details

  • Author(s)
  • C. Saunders and I. Hoskins
  • Date
  • 16 March 2017
  • Subject(s)
  • Food safety