Calorie restriction increases lifespan in worms, researchers have found.
The study, conducted by Duke University researchers, found that calorie restriction increases longevity and slows ageing in C. elegans.
Researchers said that calorie restriction led to arrested development in C. elegans. But, when food was freely available, the worm began to grow naturally and lived twice as long as worms on other diets.
"It is possible that low-nutrient diets set off the same pathways in us to put our cells in a quiescent state," said David R. Sherwood, an associate professor of biology at the Duke University. "The trick is to find a way to pharmacologically manipulate this process so that we can get the anti-aging benefits without the pain of diet restriction."
A recent study had shown that monkeys on a caloric-restricted diet age slowly and live longer than their well-fed peers. Other researchers have found that low calorie diets increase longevity by protecting the body against diseases.
For the study researchers focused on the last two stages of C. elegans larval development called as L3 and L4. During these stages, the worm develops a speck of three cells to a mass of 22 cells. Researchers found that when worms were deprived of food, the developmental stages stopped and the worm vulva had either three cells or 22 cells. According to the team, all the tissues in the worm's body had suspended development until it got enough food.
"Development isn't a continuous nonstop process," said Schindler, lead author of the study. "Organisms have to monitor their environment and decide whether or not it is amenable to their development. If it isn't, they stop, if it is, they go. Those checkpoints seem to exist to allow the animal to make that decision. And the decision has implications, because the resources either go to development or to survival."
According to the researchers, the worm can go without food for as long as two weeks. Once it gets enough nutrition, it comes out of the arrested development stage and lives twice as long as other well-fed worms.
Sherwood and colleagues said that the study could help scientists understand not just longevity, but also cancer. Some cancers stop growing after reaching a certain size and then start growing years later. Researchers say that the pathways controlling lifespan in worms could be analogous to the pathways that control human cancer growth.
The study is published in the journal PLOS Genetics.
Note that the study was conducted on humans. Whether or not strict dieting helps humans live longer isn't clear.