A recent study is calling into question the risks posed to humans from the consumption of food grade titanium dioxide. Whilst the research was unable to pinpoint specific risks, it did call for further research into the effects of TiO2 on human organs, as well as questioning if particle size can make a difference.

The study, which was published in the journal ‘Nanotoxicology’, was conducted by the Dutch National Institute for Public Health and the Environment (RIVM), and included an investigation which came in two parts, which the RIVM describes as follows:

“First, RIVM estimated the amount of titanium dioxide nanoparticles that the Dutch consumer daily ingests via food, food supplements and toothpaste. This was calculated by using measured concentrations in food products and toothpaste, which were linked to information on the intake of food products. The products contributing most to the intake of TiO2 are toothpaste (in young children only), candy, coffee creamer, fine bakery wares and sauces.

Second, RIVM performed a risk assessment by estimating the concentration of titanium dioxide nanoparticles in human liver, and subsequent comparison to the concentration in the liver of test animals for which adverse effects were found. The accumulation of particles in time was taken into account in these calculations.”

With these actions completed the research team were able to state the following, “Based on this investigation and considering the differences between man and animals and sensitive people, it appears that liver effects cannot be excluded. To gain better insight into the likelihood of effects after long-term exposure (such as via food), further research is recommended.”

Much of the concern is based around the unknown effects of TiO2 when it is consumed in different particle sizes. As the RIVM report explains, “No limit has been set for the amount of titanium dioxide that man can daily ingest. It is nowadays known that very small particles, such as nanoparticles, can behave differently from larger particles of the same chemical composition. The small particles have a relative large surface area and can therefore be reactive and may cause harmful effects. In addition, they may end up at different sites in the human body.”

Meanwhile, Dr Emma Davies reporting for ChemicalWatch recently quoted a report conducted by the Scientific Panel of the European Food Safety Authority (ANS), when she stated that, “Although food grade titanium dioxide is not considered a nanomaterial, it may contain about 3% nanoparticles, reports the ANS. It says studies show that most titanium dioxide passes through the body unchanged but that ‘a small amount’ (up to 0.1%) can be absorbed in the gut and distributed to organs.”

She continues by observing how, “The ANS was unable to set an acceptable daily intake (ADI) because of a lack of information. Additional testing on food grade titanium dioxide, such as an extended 90-day rodent study or a multi-generation or extended one-generation reproductive toxicity study (Eogrts), ‘would help to clarify possible reproductive effects and provide more comprehensive data for deriving an ADI’.

Analysis of the EFSA report  into the effects of TiO2 on human health, finds that, “The Panel noted that possible adverse effects in the reproductive system were identified in some studies conducted with material which was either non-food-grade or inadequately characterised nanomaterial (i.e. not E 171). There were no such indications in the available, albeit limited, database on reproductive endpoints for the food additive (E 171).”

So it seems that while some studies have found a link between TiO2 and a negative effect on human health (mostly in the liver or reproductive organs) for now it has been deemed safe for human consumption.

That said, the versatile food additive chemical is not yet free and clear, as both reports make clear that there is little information available for analysis, and that further research is needed ‘to fill data gaps’.

However, perhaps what is most interesting from the report is the question mark remains on the importance of particle size of chemicals. As the RVIM report says, “It has become clear that nanoparticles can behave differently as compared to larger particles or soluble substances.”

And if this is the case, how certain can we be of the safety of so many other chemical food additives?

Photo credit: RVIM