Nano-sized chemical in sunscreen, cosmetics could cause cancer, say scientists

Companies in the cosmetics and sunscreen industry may need to rethink the use of nano-sized zinc oxide in their products, warned a group of scientists on Tuesday.

Preliminary research has found that the chemical, when used in its tiniest form, could enter human cells, damage the cell’s DNA and cause cancer, according to researchers from the Nanyang Technological University (NTU) and National University of Singapore (NUS).

They noted, however, that there’s no cause for alarm yet because the study, which was published in the November edition of Biomaterials, a top journal in the field, is still in its early stages.

Known for its effectiveness in protecting the skin against ultraviolet (UV) light, zinc oxide is frequently used in sunscreens and cosmetic creams that boast of strong UV protection. 

As the compound also fights odours and bacteria, it is used in fabrics and food packaging, and is also present in baby powder, calamine lotion, anti-dandruff shampoos and antiseptic ointments.

When used in its regular-sized form, the presence of zinc oxide in sunscreens is harmless to humans. It sits on the skin’s surface and fends off harmful UV rays effectively.

But since the compound, when used in its regular-sized form, causes sunscreen and cosmetics to appear white in colour, companies are opting to use nano-sized zinc oxide particles instead.

The study, led by Materials Science and Engineering assistant professors Joachim Loo and Ng Kee Woei, found that when the nano-sized zinc oxide enters the human cell and damages DNA, some damaged cells end up multiplying freely and develop into cancerous tumours.

All this sounds scary enough, but you don’t necessarily need to dump all your expensive creams and sunscreens yet.

“As of now, there’s no cause for alarm. It doesn’t mean that if you use a certain product that contains zinc oxide, then you can actually get cancer,” Ng was quoted as saying by Channel NewsAsia.

“This is a preliminary study on cell cultures. The next step is to show the same thing happens in animals, before we can actually consider whether the same effects can be shown in humans,” he added.

More studies need to be done to find out just how much zinc oxide needs to be in a product before the product could cause cancer, or what are the other nano-sized particles that could cause cancer.

Loo, Ng and their team also hope now to get more scientists on the nanotoxicology research bandwagon, as they believe these nanomaterials can also be directed to killing cancerous cells.

“This study points to the need for further research in this area, and we hope to work with the relevant authorities on this,” said Loo.