Tiny but scary ingredients

Many of today's consumer products are made using nanotechnology, including food packaging, pots and pans, and personal-care products such as sunscreens. I interviewed my nanoengineering-expert colleague, Michael Hansen, Ph.D., about nano ingredients used in cosmetics, a worrisome trend.

What is nanotechnology? Nanoengineered ingredients are slightly larger than the size of atoms and molecules, or about a hundredthousandth the width of a human hair. When particles become that tiny, they behave differently. Titanium dioxide, used in sunscreens, for example, goes from white to almost clear. 

Are nano ingredients safety-tested? Not adequately. If a compound has been determined to be safe, then different-sized versions are considered safe. Although that rule is true in general, it breaks down on the nano level.

Which ingredients used in personal-care products are nanoengineered? Most of the titanium dioxide and zinc oxide used in sunscreens are nanoengineered. Nanosilver might be added to cosmetics, bandages, or toothpaste, and fullerenes might be put in anti-aging skin creams. 

Should we be worried? Yes. Their tiny size means that they might be able to breach the blood-brain or the placental-fetal barrier and cause damage. Recent studies found that when swallowed, nano-titanium dioxide can cause a type of DNA damage that could lead to cancer. If it gets into the bloodstream of a pregnant mouse, it can cause reproductive and brain problems in the offspring. 

What if you want to avoid nano? There are no labeling requirements, so you can never know for sure whether something uses nano materials. But you can scan ingredient lists and avoid those with titanium dioxide, zinc oxide, fullerenes (or c60), and liposomes—designed to deliver ingredients deeper into the skin.

— Urvashi Rangan, Ph.D., director of the Consumer Reports website GreenerChoices.org.

This article first appeared in the September 2010 issue of ShopSmart magazine, on newsstands now.