Plenty of stress out there, but will it make you gray?

Published 5:00 am Thursday, March 12, 2009

When we start getting gray hair, we tend to blame stress. But the link is little more than folk wisdom, unsupported by scientific studies. That didn’t stop speculation that the newly noticed salt and pepper above President Barack Obama’s temples were the first physical manifestations of some of the highest job pressures on the planet.

A more likely explanation is that Obama is starting to turn gray for the same reasons other people do. He’s getting older. The age of graying seems to be determined by heredity, The Journal of Investigative Dermatology reported in 2005. But how and why hair ages this way is not well understood.

Last month, a team of European researchers achieved something of a eureka moment. They had been studying a genetic defect called vitiligo, which results in patches of skin that have no pigment. People with vitiligo have low activity of catalase, an enzyme that breaks down hydrogen peroxide.

Given that graying hair results from an absence of pigment, it occurred to the scientists that hydrogen peroxide and catalase might play a critical role in the process. Every hair cell makes a little hydrogen peroxide, but over time the amount builds up. The European team discovered that this buildup ended up blocking the normal synthesis of melanin, the natural pigment in hair.

Our hair, it turns out, bleaches itself from the inside out. And by identifying the chemicals involved, researchers may be closer to understanding if the graying is influenced by stress.

“Now it becomes possible to understand whether stress is involved in the process; before this, we didn’t know what to look for,” said Dr. Gerald Weissmann, editor in chief of The FASEB Journal, which published the study last month.