The skin game

Nutrition Action Healthletter, July-August, 2003 by David Schardt

"People don't use sunscreen all the time, so substances with sun-protecting properties--presumably lycopene in tomato paste--could provide some degree of protection," she explains. "But the study showed that a person would have to eat lycopene-rich foods for several months before they saw a benefit."

What's more, the trial was too small and short-term to say whether lycopene can protect the skin against long-term skin damage.

"No one has scientifically demonstrated a significant protection or reversal of wrinkling or photo-aging from foods or supplements that contain antioxidants," says Jeffrey Blumberg, Chief of the Antioxidants Research Laboratory at the Human Nutrition Research Center on Aging.

Gimme Some Skin

If you can't eat or take enough antioxidants to protect your skin, how about rubbing them on?

"Applying them directly is one way to solve the problem of getting additional antioxidants into the skin," says Duke University's Sheldon Pinnell. But for that to work, several obstacles have to be overcome.

"Antioxidants are inherently unstable compounds and many of them are deeply colored," Pinnell points out. "That makes them difficult to formulate in an acceptable, stable product for cosmetic use." (Pinnell consults for a Texas "cosmeceuticals" company that markets a vitamin C cream he helped develop.)

What's more, the concentrations of antioxidants need to be substantial, and they have to protect against sunburn, photo-aging, and skin cancer.

"With a combination of topical vitamin C and vitamin E, you can get about a four-fold protection against UV-induced reddening and DNA damage in the skin of pigs," says Pinnell. (Pig skin is virtually identical to human skin.) That's comparable to a weak sunscreen.

"The same protection may occur in humans," he adds. "But, so far, there is very little research to show that."

The bottom line: Research on cosmeceuticals is in its infancy. "I haven't seen any data that establishes the efficacy of topically applied antioxidant preparations, either to reduce oxidative stress or to prevent aging," says Boston University's Barbara Gilchrest.

"Frankly, I don't think anybody really knows to what degree antioxidants get into the skin in an effective form, to what degree the skin's ability to handle oxidative stress is already maxed out, or even which antioxidants would be helpful if delivered in an effective form."

(1) Journal of Nutrition 131: 1449, 2001.

RELATED ARTICLE: Here comes the sun.

"I am completely convinced that sunscreens are helpful in preventing skin cancers and aging of the skin caused by too much sun exposure," says Barbara Gilchrest, chair of the department of dermatology at the Boston University School of Medicine.

"Photons [light particles] are the problem. They're ultimately what causes cancer and damages the skin. And sunscreens absorb or reflect photons. So just on a purely logical basis, they have to help."

Proving that in humans would be difficult, she adds, because skin cancer and photo-aging take decades to develop. "But it's been shown in animal studies that the long-term use of sunscreen definitely reduces cancer and photo-aging."