Morsani College of Medicine

Dermatology & Cutaneous Surgery

The Vigilant Hypochondriac: The reason for gray hair may offer insight into cancer prevention

By Tom Valeo, Special to the Times
In Print: Wednesday, October 28, 2009

Years ago teenagers would comb hydrogen peroxide into their hair to give themselves a sun-bleached look. Little did they know they were applying the very same substance that, years later, would give most of them at least some gray hair. The only difference would be that the peroxide would be produced by their hair follicles, not the bottle.

Scientists have finally figured out that the natural buildup of hydrogen peroxide in hair follicles causes hair to lose its color. (“Gray” hair actually consists of white hairs mixed with the remaining colored hairs.)

This buildup occurs naturally in everyone, but normally the body releases an enzyme called catalase, which breaks the caustic peroxide down into harmless water and oxygen. As people age, however, this process slows down, allowing the peroxide to accumulate and damage the melanin cells containing the pigment that gives our hair and skin its color.

On top of that, the aging body also produces lower levels of the repair enzymes that help cells recover from peroxide damage, according to scientists in England and Germany who recently discovered how hair loses its color. This process inhibits another enzyme called tyrosinase, which promotes the production of melanin.

Hydrogen peroxide, produced by cells throughout the body, promotes the creation of free radicals, which contribute to the aging process by damaging cells. That’s why scientists have long suspected that peroxide had something to do with causing hair to lose its color — something finally explained by the recent research published by the Federation of American Societies for Experimental Biology.

“This paper sounds very rational,” said Dr. Mary Lien, assistant professor in the Department of Dermatology and Cutaneous Surgery at the University of South Florida in Tampa. “The findings support the theory that the melanocyte cell death in the aging hair follicle is caused by free radical damage — a process very similar to skin aging.”

Knowing what causes hair to turn white may have benefits beyond the cosmetic. Since melanin is produced by melanocytes, the cells that turn deadly in the type of cancer known as malignant melanoma, figuring out how the body shuts them down might contribute to the prevention and treatment of the disease. And if this process involves DNA damage, it might open new avenues to fighting cancer throughout the body.

But what about gray hair itself? Now that scientists know what causes it, can they “cure” it?

“This new insight could open new strategies for intervention and reversal of the hair graying process,” the scientists state in their paper.

Lien concurs.

“There have been hints for many years regarding that,” she said. “It would be analogous to a face mask containing antioxidative creams, or similar to UV protective sprays for the scalp, or conditioners. But how this pans out remains to be seen.”