Calorie Restriction Extends Life Span Significantly in Short-Lived Primates
The practice of calorie restriction slows aging to a degree that scales with species life span. Short lived species exhibit a sizable gain in maximum life span, while long-lived species do not. In this paper, researchers report on a study of calorie restriction in grey mouse lemurs, one of our more distant and short-lived primate cousins. The effects are about as dramatic as those observed in mice, and the study is interesting on that point: lab mice normally reach 50% mortality due to aging after 2-3 years while the lemurs used here reach that point at 6-7 years, so one might have expected the lemurs to exhibit much smaller gains in life span as a result of calorie restriction. Nonetheless, by the end of the study, the longest surviving non-calorie-restricted lemurs had been dead for a year, while more than a third of the calorie restricted animals were still alive. Calorie restriction extended the 50% mortality age from 6-7 years to 9-10 years in this species, quite similar to the relative size of results in mice.
Caloric restriction, i.e., reducing calorie availability by ~20-50%, is one of the rare known strategies that can extend lifespan. In short-lived species such as rodents, caloric restriction can increase maximal lifespan up to 50% while improving general health and decreasing aging-associated diseases. Beneficial effects of caloric restriction on age-related diseases have also been reported for long-lived species, including rhesus monkeys.
Here we examine the effects of caloric restriction on the health and lifespan of the grey mouse lemur Microcebus murinus, a small lemurid primate with a median survival in captivity of 5.7 years for males and maximum lifespan of 12 years. Mouse lemurs are widely used models for human ageing. They display age-related alterations of their sensorial system, motor functions, biological rhythms, and immune and endocrine systems. In this species, aging leads to increased prevalence of diseases such as neoplasia or sarcopenia and glucoregulatory function alterations that also increase with aging in humans. Finally, their cerebral aging profile is similar to that of humans.
Because of their reduced lifespan (as compared to rhesus macaque), cohorts of calorie-restricted lemurs can be easily created to evaluate mechanisms leading to caloric restriction-related changes. Here we provide the first complete set of caloric restriction-related survival data for a non-human primate in association with a longitudinal follow-up of age-associated alterations in cognition and brain volumes.
In 2006, 34 captive adult male mouse lemurs (age 3.2 ± 0.1 years) were randomly assigned to either a control diet or a chronic 30% caloric restriction diet. Compared to control animals, caloric restriction extended lifespan by 50% (from 6.4 to 9.6 years, median survival), reduced aging-associated diseases and preserved loss of brain white matter in several brain regions. However, caloric restriction accelerated loss of grey matter throughout much of the cerebrum. Cognitive and behavioural performances were, however, not modulated by caloric restriction. Thus chronic moderate caloric restriction can extend lifespan and enhance health of a primate, but it affects brain grey matter integrity without affecting cognitive performances.
34 isn't huge but still the strongest study pointing to calorie restriction maybe working in humans IMO.
I really cannot understand why researchers spend so much time and money on CR? We know for 20 years -- this is a dead end. This will not allow people to live 200 or 300 years. Why don't work on damage which in principle can produse meaningful repair? Why don't these researchers work on lipofuscine, for example? I don't know anyone who work on lipofuscine therapy!
First of all, dismissing the vast majority of evidence about CR should disqualify you as an intelligent human. Second, all studies done on human dietary factors are always going to be suspect because so many humans either do not follow their prescribed diet to a T, not do they always honestly or accurately account their dietary behaviors.
Being able to control all aspects of a rat's life in a lab is a far cry from being able to record a similarly controlled environment for a human. Even if a group of humans agree to a short period of time to such a controlled environment it is only temporary. The remainder of those humans lives will be free wheeling eating.
True CR is years away in human measurement.
I think I personally could be an interesting testimonial on the question of CR. I have been eating consequently about 30+% less since i was around 30 years. Up to 60 years my weight was always on the low normal end (BMI about 2o to 21), but due to certain changes of life circumstances, I then changed my eating habits, to contain significantly more (good) fats and somewhat more meat, but the food quality is much more ecological than before.
Today I am 73, but since years my BMI is 24-25, but I feel and objectively(also clearly seen in my handwriting--I am among other things also graphologist) have more energy and agility (helped by living with much movement on a small ranch) than ever before in my life and look younger than my age and am generally more active also intellectually and in music. Why I weigh more than years ago could eventually be related to later eating habits than before, but still, I consequently eat 30-35% fewer calories than normal for my age and activity level.
"First of all, dismissing the vast majority of evidence about CR should disqualify you as an intelligent human."
James:
Presumably, you were responding to Ariel's comment. If you carefully read Ariel's comment, there was no dismissal of any evidence. Ariel was making the point that calorie restriction will likely not make significant gains in life extension in humans. That seems to be true based upon the evidence. For example in the UW study, there was less than 10% in life extension from calorie restriction in male monkeys.
I don't think you should be questioning other people's intelligence.