Writing July 10 in the journal Science, a team of researchers at the University of Wisconsin-Madison, the Wisconsin National Primate Research Center and the William S. Middleton Memorial Veterans Hospital reports that a nutritious but reduced-calorie diet blunts aging and significantly delays the onset of such age-related disorders as cancer, diabetes, cardiovascular disease and brain atrophy.
"We have been able to show that caloric restriction can slow the aging process in a primate species," says Richard Weindruch, a professor of medicine in the UW-Madison School of Medicine and Public Health who leads the National Institute on Aging-funded study. "We observed that caloric restriction reduced the risk of developing an age-related disease by a factor of three and increased survival."
During the 20-year course of the study, half of the animals permitted to eat freely have survived, while 80 percent of the monkeys given the same diet, but with 30 percent fewer calories, are still alive. . . .
In terms of overall animal health, Weindruch notes, the restricted diet leads to longer lifespan and improved quality of life in old age. "There is a major effect of caloric restriction in increasing survival if you look at deaths due to the diseases of aging," he says.
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," says Weindruch.
In addition, the brain health of animals on a restricted diet is also better, according to Sterling Johnson, a neuroscientist in the UW-Madison School of Medicine and Public Health. "It seems to preserve the volume of the brain in some regions. It's not a global effect, but the findings are helping us understand if this dietary treatment is having any effect on the loss of neurons" in aging.
In particular, the regions of the brain responsible for motor control and executive functions such as working memory and problem solving seem to be better preserved in animals that consume fewer calories.
I will point out that this is no surprise to anyone who has studied medieval history and noticed that almost all of the really old men were monks.