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Caloric Restriction Extends Lifespan in Primates

A 20-year study in adult rhesus monkeys has shown that caloric restriction (CR) in these primates can extend healthy lifespan. At the end of the study, 37 percent of the control group had died of age-related causes, while only 13 percent of the CR group had. This finding means that the control monkeys experienced a death rate from age-related conditions such as diabetes, cancer, cardiovascular disease, and brain atrophy almost three times that of the CR group. Previous studies with yeast, worms, flies, and rodents have suggested that this kind of caloric restriction–a reduction of about 30 percent, and very different from malnutrition–can lead to such health benefits in some mammals, but given the many parallels between rhesus monkeys and humans, this study suggests that these benefits might occur in humans as well. "We have been able to show that caloric restriction can slow the aging process in a primate species," said Dr. Richard Weindruch, senior author of the study. "We observed that caloric restriction reduced the risk of developing an age-related disease by a factor of three and increased survival." The incidence of cancerous tumors and cardiovascular disease in animals on a restricted diet was less than half that seen in animals permitted to eat freely. Remarkably, while diabetes or impaired glucose regulation is common in monkeys that can eat all they want, it has yet to be observed in any animal on a restricted diet. "So far, we've seen the complete prevention of diabetes," said Dr. Weindruch. Furthermore, he noted, "The atrophy or loss of brain mass known to occur with aging is significantly attenuated in several regions of the brain. That's a completely new observation." The results of this study were published in the July 10 issue of Science. The image is copyright the University of Wisconsin-Madison by Jeffrey Miller. [Press release]