Scientists have discovered
why humans get gray hair as they age. Essentially, gray hair is caused when the body creates too much hydrogen peroxide. Our bodies naturally make hydrogen peroxide, but when there is too much it interferes with melanin, the pigment that colors hair.
The body also produces the enzyme catalase, which breaks down hydrogen peroxide into water and oxygen. Or at least it does for a while. As we age, catalase production tails off, leaving nothing to transform the hydrogen peroxide into chemicals the body can release.
So, as hydrogen peroxide builds up, we go gray, concluded researchers at the University of Bradford in the United Kingdom, who last week published the results of a study in the Federation of American Societies for Experimental Biology's online journal.
"This new insight could open new strategies for intervention and reversal of the hair graying process," wrote the study's lead author John Wood, who died last month.
The studies were based on analysis of cell cultures of human hair follicles.
In addition to lacking catalase, the follicles of gray-haired people also had far fewer hair-repair enzymes, which in turn drove down production of melanin, the scientists found.
Genetics are also involved in how fast people go gray. Scientists say that Asians go gray later than Caucasians. And if you're asking "why in the world do we produce hydrogen peroxide in our bodies?" the answer is that the chemical kills bacteria. The authors of the study believe there will be a product on the market to stop or reverse gray hair in the near future.
Scientists have 
