Washington ? A substance found in red wine protected mice from the ill effects of obesity, raising the tantalizing prospect the compound could do the same for humans and may also help people live longer, healthier lives, researchers reported Wednesday.

The substance, called resveratrol, enabled mice that were fed a high-calorie, high-fat diet to live normal, active lives despite becoming obese – the first time any compound has been shown to do that. Tests found the agent activated a host of genes that protect against the effects of aging, essentially neutralizing the adverse effects of a bad diet on the animals’ health and lifespan.

Although much more work is needed to explore the benefits and safety of the substance, which is sold over the counter as a nutritional supplement, the findings could lead to the long-sought goal of extending the healthy human lifespan, experts said. Preliminary tests in people are already under way.

“We’ve been looking for something like this for the last 100,000 years, and maybe it’s right around the corner – a molecule that could be taken in a single pill to delay the diseases of aging and keep you healthier as you grow old,” said David A. Sinclair, a Harvard University molecular biologist who led the study. “The potential impact would be huge.”

The findings triggered excitement among scientists studying aging, who hailed the findings as groundbreaking.

“This represents a likely major landmark,” said Stephen Helfand, who studies the molecular genetics of aging at Brown University. “This really pushes the field forward. It’s quite exciting.”

The research, being published in today’s issue of the journal Nature, helps explain a host of observations that have long intrigued researchers, including why French people, who drink a lot of red wine, tend to get fewer heart attacks.

In the hope of finding a drug that could harness the natural life-extending capabilities activated by caloric restriction, Sinclair and his colleagues identified a number of promising compounds, including resveratrol, which is found in red wine, grape skins and other plants. The compound, which increases the activity of enzymes known as sirtuins, prolonged the lifespan of every organism scientists have tested it on, including yeast, worms, fish and fruit flies.

The researchers cautioned that the findings should not encourage people to eat badly, thinking resveratrol could make gluttony completely safe.

They also noted that a person would have to drink at least 100 bottles of red wine a day or take mega doses of the commercially available supplements to get the levels given to the mice, which may not be safe in humans.