Aug. 30—In the late 1980s, scientists set out to test the theory that dietary restriction could extend the life span of long-lived primates, as decades of studies had found it did in mice and other lower organisms. If true, this would strongly imply that the same assumptions could be made about humans.
Two independent teams—one at the U.S. National Institute on Aging in Bethesda, Md., and the other at the Wisconsin National Primate Research Center in Madison, Wis., each placed rhesus monkeys on diets that contained 30 percent fewer calories than normal and have periodically provided updates on the health and longevity of the animals.
As the latest Nature dispatch found, the NIA monkeys fed a calorie-restricted diet didn't live any longer than monkeys on a higher-calorie diet. No matter what they ate, maximum lifespan seems to hover around 40 years of age. Half the monkeys that began the study as youngsters were still alive, but the researchers say, based on survival patterns, they predict the remaining calorie-restrictors and controls will all live to be about the same age.