Dietary restriction increases lifespan

Dietary restriction or limited food intake without malnutrition has beneficial effects on longevity in species, including humans, a new study has found.

The study published in the journal PLoS Genetics reveals understanding on how dietary restriction leads to increase in lifespan and impacts autophagy in the intestine.

Autophagy which plays a role in lifespan extension involves breaking down of the cell's parts -- its protein-making, power-generating and transport systems into small molecules.

"In this study, we used the small roundworm C. elegans as a model to show that autophagy in the intestine is critical for lifespan extension," said Malene Hansen, Associate Professor at Sanford Burnham Prebys Medical Discovery Institute.

The researchers found that the gut of dietary-restricted worms has a higher rate of autophagy, which appears to improve fitness in multiple ways like preserving intestinal integrity and maintaining the animal's ability to move around.

"We found that blocking autophagy in their intestines significantly shortened their lifespans, showing that autophagy in this organ is key for longevity," said Sara Gelino, Researcher at Sanford Burnham Prebys Medical Discovery Institute.

While normal worms' gut barriers become leaky as they get older, those of eat-2 type of worms remain intact. Preventing autophagy indicated that a non-leaky intestine is an important factor for long life, suggested the study.

The research team also observed that turning off autophagy in the intestine made the slow-eating, long-lived worms move around less.

The decrease in physical activity indicates that autophagy in one organ can have a major impact on other organs, in this case probably muscle or motor neurons, suggested the study.