Do Environmental Toxins Speed Up Aging?

It is not clear why some of us live longer than others. After all, studies of twins suggest that only about 25 percent of the difference in longevity is due to genes. Of course, some die of various diseases at younger or older ages, but seemingly similarly situated people die at different ages. One answer may be the existence of "gerontogens"—factors, including substances in the environment, that can accelerate the aging process. This is the gist of a recent paper published in Trends in Molecular Medicine by researchers at the University of North Carolina's School of Medicine and reported by the National Geographic.

Possible gerontogens include arsenic in groundwater, benzene in industrial emissions, ultraviolet radiation in sunlight, and the cocktail of 4,000 toxic chemicals in tobacco smoke. Activities may also be included, like ingesting excessive calories, or suffering psychological stress.

"The idea that environmental factors can accelerate aging has been around for a while, [but] I agree that the study of gerontogens has lagged behind other areas of aging research," says Judith Campisi of the Buck Institute for Research on Aging.

She adds that scientists have become more interested in these substances in recent years after learning that many types of chemotherapy, and some anti-HIV drugs, can speed the onset of age-related traits like frailty and mental decline.

The discovery of gerontogens does not explain everything about aging, but it offers the promise of increasing our knowledge, which then offers the potential for doing something about it. Of course, the immediate lesson is one that the world should know by now--don't smoke.