Why Calorie Restriction Might Prolong Life

Study revolves around gene that controls response to dietary restrictions.

By Amanda Gardner
HealthDay Reporter
Wednesday, May 2, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

WEDNESDAY, May 2 (HealthDay News) -- Scientists have long known that eating less translates into longer life, at least in worms and mice.

Now, researchers report that they think they know why this phenomenon of "dietary restriction" increases longevity: It all revolves around a gene known as pha-4, which is involved in the embryonic development of the intestine in the C. elegans roundworm.

"After 72 years of not knowing how calorie restriction works, we finally have genetic evidence to unravel the underlying molecular program required for increased longevity in response to calorie restriction," said study senior author Andrew Dillin, an associate professor in the Molecular and Cell Biology Laboratory at the Salk Institute in La Jolla, Calif.

"This suggests that there could be specific genetic pathways that modulate organisms' response to caloric restriction. If there are, we can now screen to find drugs to modulate," said Heidi A. Tissenbaum, an associate professor in the Program in Gene Function and Expression at the University of Massachusetts Medical School. "Also, very few people have looked at genes in embryogenesis and how they affect adult life span. Not only does this have an effect on what we understand about dietary restriction, but also what we understand about longevity. Genes that play critical roles in embryogenesis might be critically important in the aging process," she added.

Dillin reported the findings, which were expected to be published in the May 2 online issue of Nature, at a news conference Tuesday.

The discovery raises the possibility that drugs targeting this gene could confer the same health benefits as a near-starvation diet, possibly even in humans.

"We don't know that yet, but we think the gene could play a role in humans," Dillin said. "There's a primate study going on, and it looks like primates are going to respond very well to reduced intake and live longer. We have a lot of work to do to see whether or not the things that look like pha-4 in humans and mice are doing the same thing."