Restrict Calories, Live Longer?

Dec. 31, 2003 -- Drastically cutting calories on a daily basis may help at least some primitive organisms live longer and fight the effects of aging.

Although the theory hasn't been proven in humans, a new study suggests that severe calorie restriction can activate an anti-aging gene in a much less complex living organism: yeast.

Researchers found that calorie restriction in yeast cells lowered levels of an enzyme that inhibits an anti-aging gene, known as SIR2 (silenced information regulator), and allowed the longevity promoter to flourish.

Previous studies have shown that SIR2 is linked to extending life span in yeast and in the roundworm. Humans carry a similar gene.

Researchers say the findings may help explain why calorie restriction has been shown to delay the onset or prevent many age-related diseases, such as cancer and diabetes, in a variety of organisms.

Slashing Calories to Prolong Life

In the study, published in the Jan. 1, 2004, issue of Genes & Development, researchers looked at how prolonged calorie restriction affects the longevity gene.

Researchers say this gene, SIR2, makes a protein called Sir2, which is normally activated by the coenzyme NAD. But in this study, they found that a coenzyme related to NAD called NADH actually blocks the action of NAD and slows the production of anti-aging protein.

During calorie restriction, researchers found levels of NADH declined in yeast cells and allowed NAD to stimulate production of Sir2 more effectively and extended the life span of the primitive microorganisms.

Researchers say it remains to be seen whether calorie restriction in human cells would have similar effects by activating similar anti-aging genes and proteins.