Chronic caloric restriction strongly increases the lifespan of a small primate, the grey mouse lemur by 50%. This is one of the results of a ten-year experiment conducted by researchers at the CNRS and the French National Museum of Natural History (MNHN), in partnership with other French teams.1 Chronic caloric restriction consists in eating a reduced but balanced diet from the outset of early adulthood. Its beneficial effect on lifespan had been established for many short-lived species (worms, flies, mice), but remained controversial for primates, including humans. Another observation is that the aging process is delayed among animals on a reduced diet.
The scientists exposed a group of mouse lemurs to moderate chronic caloric restriction (30% fewer calories than their peers consuming a normal diet) from the outset of early adulthood. They then considered their survival data as well as possible age-related alterations. The first result, after the experiment had been running for ten years, was that in comparison to the animals in the control group, the lifespan of those subject to caloric restriction increased by almost 50%. More specifically, their median survival is 9.6 years (compared to 6.4 years for the mouse lemurs in the control group). And, for the first time among primates, the scientists observed that the maximum lifespan had increased: almost a third of the calorie-restricted animals were still alive when the last animal in the control group died at the aged of 11.3 years.
The results indicate that chronic caloric restriction is currently the most effective way to extend maximum lifespan and delay the aging process in a non-human primate. The next step for the scientists is to associate chronic caloric restriction with another study parameter, such as physical exercise, in an attempt to further extend the upper limits of lifespan.
Caloric restriction increases lifespan but affects brain integrity in grey mouse lemur primates. Pifferi F, Terrien J, Marchal J, Dal-Pan A, et al. Communications Biology. April 5, 2018.
The health benefits of chronic caloric restriction resulting in lifespan extension are well established in many short-lived species, but the effects in humans and other primates remain controversial. Here we report the most advanced survival data and the associated follow-up to our knowledge of age-related alterations in a cohort of grey mouse lemurs (Microcebus murinus, lemurid primate) exposed to a chronic moderate (30%) caloric restriction. 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.