At least in rhesus monkeys. As long-time readers of this blog know, I usually don’t comment on animal studies. But, the likelihood of these data applying in humans is, in my opinion, so high, I wanted you to be aware of the details. And remember as you read these comments, that the monkeys in the group consuming higher calories, were still eating a heathy diet. This is NOT true for most humans!
In a front page story, the New York Times reports that, according to research published in the journal Science, “people could … fend off the usual diseases of old age and considerably extend their life span by following a special diet.”
The approach, “known as caloric restriction,” involves a diet that contains “all the normal healthy ingredients, but” with “30 percent fewer calories than usual.”
Past research has shown that “mice kept on such a diet from birth” may “live up to 40 percent longer than comparison mice fed normally.”
To investigate whether the same would “be true in people,” researchers began “two studies of rhesus monkeys” over “20 years ago.”
The Wall Street Journal reports that findings from one of those studies “appear to validate” the “technique … as a way to live longer,” providing “new impetus to researchers and companies” that “are searching for a drug to mimic the beneficial effects of a meager diet in humans without the feeling of near-starvation.”
The study “began in 1989 with 30 rhesus monkeys and added 46 more in 1994.” Researchers restricted “half the monkeys’ diets, reducing their calories by 30 percent, when the monkeys were fully grown, or about 10 years old.”
The Los Angeles Times reports, “Over the course of the study, the monkeys that ate the regular diet were three times more likely to die of an age-related disease than their counterparts on caloric restriction.”
These results were “welcomed by scientists who study the biological mechanisms of aging and longevity.” Susan Robergs, of the Human Nutrition Research Center on Aging at Tufts University, noted that “it adds to the evidence piling up that caloric restriction … is a healthy way to stay alive and healthy longer.”
But, Dr. David Finkelstein, of the National Institute on Aging, noted that “what we would really like is not so much that people should live longer, but that people should live healthier,” the AP reports.
In fact, “the calorie-cut monkeys” in the study “had less than half the incidence of cancerous tumors or heart disease of the monkeys who ate normally.”
Researchers also found using brain scans that the “dieting monkeys” had “less age-related shrinkage.” Furthermore, the calorie-restricted monkeys appeared “many more years younger.”
The researchers noted, however, that their efforts were aimed at “studying calorie restriction, not malnutrition,” CNN reports. The monkeys “consumed very healthful diets” in both groups, including “15 percent protein and 10 percent fat.” Their diets were also “enriched with vitamins.” Still, “exactly how a calorie-restricted diet helps stave off age-related diseases and extend lifespan is unknown.”
According to Felipe Sierra, director of the biology of aging program at the US National Institute on Aging, “the ultimate value of this” research “will be to unveil the physiological mechanisms behind a slowdown in the aging process, and then to come up with ways to mimic those processes with drugs,” HealthDay reported.
Sierra added that “the idea that dietary restriction extends lifespan in all species is not true.” In fact, “many strains of rats and mice do not respond,” and “in some strains, it’s actually deleterious.”
The researchers also found that “the diet may … have a mental benefit,” MedPage Today reported. The study showed that “animals on calorie restriction had significantly slower rates of age-associated brain atrophy in some regions than controls.”
In addition, “animals on the low-calorie diet had significantly better preservation of volume” of “regions involved in motor and executive functions.”
The researchers said that “studies to test whether those differences have an effect on mental function are still under way.”
So, the bottom line from these data: Eat a healthy diet and try to keep your daily caloric intake below 2000 calories.
The bottom line from other data: Increase your physical activity and be sure you get plenty of restful sleep.