BEIJING, June 5 (Xinhuanet) -- For 70 years scientists have known that fruit flies, mice, dogs and other animals on near-starvation diets tended to live up to 40 percent longer than those with better diets, and a recent study now reveals why.

    Reseachers at the Salk Institute for Biological Studies in La Jolla, California, have identified a gene in roundworms that directly connects calorie restriction to longer lifespan.

    Research leader Andrew Dillin said a gene called pha-4 plays a role in gut development in embryonic worms but in adults is associated with calorie-restricted longevity. Dillin said it is unclear whether similar genes may play a similar role in humans.

    "We don't know yet whether or not dietary restriction will increase longevity in humans," Dillin said. "There are several people that are actively doing this voluntarily.

    "But there is a primate study that's going on that's around 35 years into it," he added, "and it looks like the primates are going to respond very well to reduced food intake and actually live longer."

    Dillin said it usually takes a 50 to 70 percent reduction in normal food intake to yield longer lifespan in animals.

    People have three genes very much like the worm's pha-4. They are related to glucagon, a pancreatic hormone that increases blood sugar concentration and maintains the body's energy balance, particularly during fasting.

    Identifying the worm gene might open the door to drugs that imitate the effects of calorie restriction and could allow people to live longer without following such a severely restrictive diet, the researchers reported the journal Nature.

    (Agencies)