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How the world got lost on
the road to an anti-aging pill
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August 30, 2012: by Bill Sardi
Members of the Calorie Restriction Society are likely throwing an ice cream party tonight knowing their limited calorie diet may not double their lifespan as it has in laboratory animals. But wait. Hold up on those banana splits till the science gets sorted out.
The quest to live longer is not embraced by many. Most desire quality over quantity of life. But for those who would like to achieve superlongevity via calorie restriction, a recent study has, at least temporarily, dashed their hopes.
The problem with the nonsense science you will be reading in the next few days is that biologists may be using the wrong markers of disease and aging and are too quick to give up on calorie restriction before sorting out its own science.
The news released today from the National Institute on Aging (NIA) is that monkeys fed a limited amount of calories and a limited volume of food overall did not live longer than monkeys fed a normal calorie diet. You can get a visual image of these thinner but not-longer-lived animals by clicking here.
The data is not entirely conclusive, it is based upon projected deaths (said to be within 0.1% probability), but it runs contrary to what was reported in 2009 among calorie-restricted monkeys who were fed ad libitum (eat as much as they like). This other group of monkeys, housed in a laboratory at the University of Wisconsin, lived 30% longer on a calorie-restricted diet.
Both studies were launched in the 1980s and researchers have just now been able to compare survival data. There was no difference in the causes of death between these two diet groups. But analyzing the data gets a bit tricky because some of the Wisconsin animals were subjected to experiments that led to non-aging-related causes of death. When those deaths were eliminated, calorie restriction did show a statistically significant positive effect upon survival in the animals at the Wisconsin lab. So hold the ice cream.
But which group more closely resembles the modern human situation, the animals that were given a limited amount of food and calories, or the animals that were allowed to eat all they wanted from less calorie-rich food? Certainly overfed Americans who consume a fat and sugar-rich diet and raid the refrigerator at will would more resemble the animals at the Wisconsin lab where calorie restriction did produce greater survival.
In the Wisconsin animals, 13% of the dieting group died from age-related causes compared with 37% of the group that ate a normal-calorie diet. An analytic report published in Nature magazine said “One reason for that difference could be that the Wisconsin monkeys were fed a less healthy diet, which made the calorie-restricted monkeys seem healthier by comparison simply because they ate less of it.”
The monkey diet at the Wisconsin primate center provided 28.5 sucrose compared to 3.9% at the National Institute on Aging animals. Also the NIA diet was supplemented with fish oil and antioxidants, the Wisconsin diet was not.
A Reuters news report said a comparative analysis of the two studies “suggests the longevity diet didn’t really extend lifespan in the Wisconsin monkeys: It only seemed to because the control monkeys ate themselves into an early grave.”
Here is where it gets confusing. If we throw out the deaths that were caused by experimentation rather than aging, the Wisconsin animals with the less healthy limited-calorie diet lived longer whereas the animals given less sugar and more antioxidants didn’t. Oh, the animals in both groups were healthier, but that didn’t translate to longevity. Make that three scoops of ice cream and forget the antioxidant topping.
One of the assumptions in both of these studies is that a calorie is a calorie, regardless of its source. One of the co-authors of the NIA study said: “When we began these studies, the dogma was that a calorie is a calorie. I think it’s clear that the types of calories the monkeys ate made a profound difference.” Advocates of low-carbohydrate diets have been saying this for years.
Is there any correlation between the findings in these monkey studies and human trials? Well, surprisingly, there is. A 10-year study of elderly men in Sweden reveals a calorie-restricted-type diet pattern slightly increased mortality whereas a Mediterranean-type diet slightly decreased overall mortality. The difference between the two groups was strikingly significant. Add some olive oil topping to the ice cream.
Cholesterol levels were lower in the limited calorie animals. But another problem in analyzing these studies is that biologists have been using the wrong markers of disease for a long time now. The assumption is that higher circulating cholesterol levels equate with mortality, particularly from coronary artery disease. But analysis of the ten largest studies using cholesterol-lowering drugs does not reveal a decline in death rates from heart disease. When will modern medicine abandon it cholesterol mantra?
Another striking factoid emanating from these studies is that 40% of the Wisconsin animals fed a normal diet with high sucrose developed diabetes whereas diabetes was completely absent from the calorie restricted animals given the same amount of sugar but fewer calories overall.
And, oops, there is another glitch in the NIA study. The control (normal diet) animals in the NIA group ate a partially restricted diet as they were given an apportioned amount of food. So, in a sense, they were mildly calorie restricted and therefore any difference in survival between them and their calorie-restricted cage-mates may have been negated. It has been reported that a 10% calorie-restricted diet in laboratory rats increased lifespan compared to ad libitum-fed animals, even more than a 25% or 40% calorie restricted diet! Uh, forget the ice cream. How about celery sticks? – © 2012 Bill Sardi, ResveratrolNews.com Not for posting on other websites.