Wendy Wolfson
RedwoodAge.com
One way to live longer and healthier may be by eating less.
A research team has says a group of rhesus monkeys, given 30 percent less food, lived considerably longer - without the ailments of aging.
The study followed a group of 76 adult male and female rhesus monkeys (between 7 and 14 years old) over a span of 20 years. Back in 1989, they observed what the monkeys normally ate, and then assigned them to either a caloric restriction group or a control group with a normal diet.
The caloric restriction group ate a nutritionally balanced diet, but had their daily allotment of food reduced by 10 percent successively for three months until they got 30 percent less calories than the control group. According to Colman, both groups were fed a highly nutritious complete diet, but the version fed to the calorie restricted animals was enriched by about 30 percent in vitamin and mineral components to account for the 30 percent decrease in food allotment.
A couple of decades later, 37 percent of the control group died of old age-related causes such as cardiovascular disease, diabetes, cancer and brain atrophy. However, only 13 percent of the calorie restricted group died.
According to the researchers' analysis, out of the animals that died of old age and not other causes, the control animals had three times the rate of dying of old age as the calorie restricted group. The study, "Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys, was published in the journal "Science" by Dr. Ricki Colman and colleagues at the Wisconsin National Primate Research Center.
Photo Evidence
The researchers also showed some striking photographs of two monkeys: Canto, 27,
from the calorie-restricted group, and Owen, 29, who ate normally. Twenty-seven
is the typical lifespan of a rhesus monkey in captivity (rhesus monkeys can live
up to 40 years.)
Looking disconcertingly like an aged human, the control animal looks decrepit, and has a sagging rear end, but the calorie-restricted monkey has a straight back and perky tail.
The researchers wondered if just because they looked younger, the
calorie-restricted monkeys were actually biologically younger than their control
colleagues. In tests and necropsies, the calorie-restricted animals had better
body composition, unimpaired glucose levels, less cancer and half the
cardiovascular disease as the control monkeys. They even had better looking
brains when they died. The team is in the process of evaluating their
skeletal status.
"We are in the process of carrying out detailed cognitive function testing
in these animals but do not yet have enough data to report on function."
Colman said. "We also have data on a motor function task that is suggestive
of a benefit but we are still in the process of evaluating this as well."
Scientists have known for a long time that caloric restriction makes yeast, fruit flies, worms and mice live longer. A research study conducted back in 1935 showed that mice with a well-balanced but restricted diet lived longer, and were slower to develop the diseases of old age.
But in the 1990's, this model was revisited as scientists looked for regulators, key genetic switches that turned on and off the aging process. A number of university labs and biotech companies are now investigating nutrient sensitive signaling molecules that could govern aging, and in the course of their research have produced some extremely long-lived and good-looking flies, worms and mice.
Humans, Too?
But are these animal models for human disease good proxies for complex processes
of human aging? Certainly monkeys are a lot closer to humans. " This is the
largest and mostly highly controlled study to show the beneficial effects of CR
on morbidity and mortality in a primate species," said Colman. "Proof
of efficacy in primates now allows us to probe mechanisms of aging that will
have relevance in humans."
Colman et al. conclude that moderately restricting calories in adulthood can delay the onset of age-related diseases in a primate species and promotes longevity.
"Given the obvious parallels between rhesus monkeys and humans, the beneficial effects of calorie restriction may also occur in humans." the researchers concluded. They cited long term studies of humans who cut back their overall calorie intake and show less cardiovascular deterioration, but say the hard part, of course, is observing true caloric restriction over an entire adult human lifespan.
Given human nature, it would be a hard experiment to do. After all, who doesn't lie on their food diary?
