rance is clamping down on a common food additive that has been shown to be carcinogenic in animal studies. The ban of titanium dioxide, announced by the French government last month, follows a review that could not rule out human cancer risks.

The ban is just the latest chapter in a long-running debate on the safety of widespread food additives known as nanoparticles, which are largely unregulated in the US. This suite of ingredients, engineered to almost atomic scale, may have unintended effects on cells and organs, particularly the digestive tract. There are also indications that nanoparticles may get into the bloodstream and accumulate elsewhere in the body. They have been linked to inflammation, liver and kidney damage and even heart and brain damage.

Technological developments over the past two decades have meant that we can now engineer tiny particles much more easily – and their unusual properties make them useful in the food industry. They are currently used to change the texture, appearance and flavor of various foods. For example, silicon dioxide is added to salts, spices and icing sugar to improve their flow. Salt and green tea are ground to nano-sized particles to boost their flavor or to improve their antioxidant properties.

Titanium dioxide, or TiO₂, appears in sweets, baked goods and milk powders, often as a whitening agent. But the tiny metal additive has also been shown to accumulate in liver, spleen, kidney and lung tissues in rats when ingested and to damage the liver and heart muscle.

Due to safety concerns, some scientists who have studied nanoparticles say they would have reservations about eating food that contains the technology.

Image Credit:  Wikipedia – Titanium(IV) oxide