Lately, many readers have been asking me my thoughts on the recent report by Nanyang Technological University (NTU) on the nano-particle sized Zinc Oxide that may cause cancer.
I first heard the news about a sunscreen and cosmetic ingredient that may cause cancer from the Chinese radio station while on my way home from work early last week. The Chinese station didn’t mention the name of the ingredient. Upon reaching home, I was actually shocked and disappointed to realize that it is the popular and potent sunscreen ingredient Zinc Oxide. And it is the nano-particle sized Zinc Oxide with very small particles that can absorb into the skin cells and may cause cancer as it has claimed.
Zinc oxide, one of the 17 FDA approved active sunscreen ingredients, is an excellent broad spectrum UV reflector that protects the harmful UVA and UVB rays. Other than Titanium Dioxide, Zinc oxide is considered the safest and most effective physical sunscreen ingredient available.
When used as an ingredient in sunscreen, Zinc Oxide, a mineral powder, is claimed to sit on the skin’s surface scattering and absorbing ultraviolet rays without being absorbed into the skin. It is non-irritating and non-allergenic, therefore it is claimed to be very suitable for sensitive skin.
As compared to the normal Zinc Oxide powder that gives an opaque white cast, the nano-particles Zinc Oxide appears transparent when applied to the skin. Because of its small particles, the nano size Zinc Oxide does not scatter light and therefore does not appear white. It is found to have superior UV blocking properties compared to its normal size particles. Therefore it is commonly used in sunscreen creams and lotions to protect against sunburn and other damage to the skin caused by ultraviolet light.
Many controversial researches have shown that these nano-sized particles Zinc Oxide may cause potential health risks. They are claimed to enter healthy human cells like the blood or the lungs and damage DNA. However, there are also reports show that particles of Zinc Oxide greater than 30nm, when applied to the skin, do not get absorbed into the body, do not enter the bloodstream, and are not a threat to human health.