Caloric restriction improves health and survival of rhesus monkeys
Nature Communications 8, Article number: 14063 (2017)
Published online:
17 January 2017
http://www.nature.com/articles/ncomms14063 Abstract
Caloric restriction (CR) without malnutrition extends lifespan and delays the onset of age-related disorders in most species but its impact in nonhuman primates has been controversial. In the late 1980s two parallel studies were initiated to determine the effect of CR in rhesus monkeys. The University of Wisconsin study reported a significant positive impact of CR on survival, but the National Institute on Aging study detected no significant survival effect. Here we present a direct comparison of longitudinal data from both studies including survival, bodyweight, food intake, fasting glucose levels and age-related morbidity. We describe differences in study design that could contribute to differences in outcomes, and we report species specificity in the impact of CR in terms of optimal onset and diet. Taken together these data confirm that health benefits of CR are conserved in monkeys and suggest that CR mechanisms are likely translatable to human health.
Calorie restriction lets monkeys live long and prosper
https://medicalxpress.com/news/2017-01- ... osper.html January 17, 2017
Settling a persistent scientific controversy, a long-awaited report shows that restricting calories does indeed help rhesus monkeys live longer, healthier lives.
A remarkable collaboration between two competing research teams—one from the University of Wisconsin-Madison and one from the National Institute on Aging—is the first time the groups worked together to resolve one of the most controversial stories in aging research.
The findings by the collaboration—including Senior Scientist Ricki Colman of the Wisconsin National Primate Research Center and UW-Madison Associate Professor of Medicine Rozalyn Anderson; and NIA Staff Scientist and Nonhuman Primate Core Facility Head Julie Mattison and Senior Investigator and Chief of the Translational Gerontology Branch Rafael de Cabo—were published today (Jan. 17, 2017) in the journal Nature Communications.
In 2009, the UW-Madison study team reported significant benefits in survival and reductions in cancer, cardiovascular disease, and insulin resistance for monkeys that ate less than their peers. In 2012, however, the NIA study team reported no significant improvement in survival, but did find a trend toward improved health.
"These conflicting outcomes had cast a shadow of doubt on the translatability of the caloric-restriction paradigm as a means to understand aging and what creates age-related disease vulnerability," says Anderson, one of the report's corresponding authors. Working together, the competing laboratories analyzed data gathered over many years and including data from almost 200 monkeys from both studies. Now, scientists think they know why the studies showed different results.
First, the animals in the two studies had their diets restricted at different ages. Comparative analysis reveals that eating less is beneficial in adult and older primates but is not beneficial for younger animals. This is a major departure from prior studies in rodents, where starting at an earlier age is better in achieving the benefits of a low-calorie diet.
Second, in the old-onset group of monkeys at NIA, the control monkeys ate less than the Wisconsin control group. This lower food intake was associated with improved survival compared to the Wisconsin controls. The previously reported lack of difference in survival between control and restricted groups for older-onset monkeys within NIA emerges as beneficial differences when compared to the UW-Madison data. In this way, it seems that small differences in food intake in primates could meaningfully affect aging and health.
Third, diet composition was substantially different between studies. The NIA monkeys ate naturally sourced foods and the UW-Madison monkeys, part of the colony at the Wisconsin National Primate Research Center, ate processed food with higher sugar content. The UW-Madison control animals were fatter than the control monkeys at NIA, indicating that at nonrestricted levels of food intake, what is eaten can make a big difference for fat mass and body composition.
Finally, the team identified key sex differences in the relationship between diet, adiposity (fat), and insulin sensitivity, where females seem to be less vulnerable to adverse effects of adiposity than males. This new insight appears to be particularly important in primates and likely is translatable to humans.
The upshot of the report is that caloric restriction does indeed seem to be a means to affect aging. However, for primates, age, diet and sex must all be factored in to realize the full benefits of lower caloric intake.
DAILY NEWS 17 January 2017
Calorie restriction diet extends life of monkeys by years
Eat less, live more?
By Clare Wilson
Put down the cake. Going on a permanent diet could make you live longer, if findings from monkeys hold true for people.
A long-running trial in macaques has found that calorie restriction makes them live about three years longer than normal, which would translate to about nine years in people.
Such a strict diet might not be for everyone, but understanding the mechanisms behind any benefits of calorie restriction may one day lead to anti-ageing medicines, says Julie Mattison at the National Institute on Aging (NIA) in Baltimore, Maryland. “The goal is to improve human health,” she says.
Many studies have shown that calorie restriction extends lifespan for lab organisms, from yeast through to worms, flies and mice. This has prompted a few thousand people to choose to restrict their calories to between 1500 to 1800 kcal a day (women and men are usually advised to consume 2000 and 2500 kcal, respectively). Their hope is it will give them longer and healthier lives, and there’s some evidence that such people have better blood cholesterol and glucose levels.
Age record breakers
But it’s unclear if the approach can really lengthen the lives of long-lived animals like us. Two trials of calorie restriction in macaques, which live around 26 years in captivity, have until now produced conflicting results.
The trials were set up in the late 1980s, and not all the monkeys have died yet. But an interim report from one group, based at the University of Wisconsin, previously found that the monkeys on a restricted diet were indeed living longer than the control group. However, the second study, run by the NIA, found there was no difference in the survival rates of their animals, which cast doubt on the entire premise.
Now the teams have compared their most recent results and their analysis backs the earlier trial that had positive findings. The NIA study, on the other hand, had several problems, including issues with the control group eating fewer calories than expected, and some of the animals beginning their restricted diet as juveniles – which reduces lifespan.
Even so, in the NIA trial, four of the monkeys that began the diet as adults lived to be over 40, breaking all known records for macaques – an observation which may cheer those who practise calorie restriction. However, picking out single results like this from a larger study isn’t good evidence, says Mattison.
Side effects
In the Wisconsin trial, animals did live significantly longer than controls – calorie-restricted males lived about two years longer, while calorie-restricted females lived about six years longer. There were also lower rates of heart disease and cancer in these monkeys. These are the major causes of death in people, lending support to the idea that the results apply to humans, says Luigi Fontana of the University of Brescia in Italy.
However, Brian Delaney, who is president of the Calorie Restriction Society, an organisation that supports the practice in people, says some who follow this diet are disappointed by the relatively modest benefits in monkeys compared with mice, which have lived up to 50 per cent longer than normal.
“Is it worth it?” asks Delaney. “My choice is to do it. But I’m so used to the diet that it really isn’t very difficult for me anymore.”
Delaney has been practising calorie restriction for 24 years. Until someone is used to it, the diet involves planning every meal with precision, and side effects can include feeling cold and reduced libido.