Life Lines

Although slimmer, calorie restricted rhesus monkeys (left) do not live longer than their age-matched counterparts (right). (Housing shown was for photo purposes only; Image: National Institutes of Aging; Austad SN, Nature 2012).
Despite promising results in mice and rats that calorie restriction prolongs lifespan, results from the US National Institute on Aging (NIA) in Bethesda, MD were just published in Nature last week and concluded that calorie restriction for primates had no effect on longevity.
 
In the study, young and old rhesus monkeys were fed either control diets or 30% reduced-calorie diets. For older males, calorie restriction had some health benefits in the form of lower cholesterol and triglycerides with moderately lower blood glucose than control animals. In contrast, young males started on the special diet showed no differences in blood glucose and only small improvements in triglycerides. Preliminary findings from the study also suggest that calorie restriction may just delay (but not prevent) the onset of age-related diseases like cancer and cardiovascular disease.

In a similar study of young rhesus monkeys (7-14 years old) at the Wisconsin National Primate Research Center, researchers found a trend towards longer lifespans for calorie restricted animals after they had discounted what they felt were not age-related deaths. This has led some experts in the field to suspect that the deaths in the restricted group may have been related to the treatment (roughly half of the total deaths were eliminated from their calculations) especially since there were a higher number of deaths that were termed non-age related in the calorie restricted group than the controls. 

Another difference between the studies was diet composition with more sucrose included in the Wisconsin trial, which may be related to the higher incidence of diabetes in the control animals in that study as compared to the NIA study. An article by aging expert Dr. Austad suspected that the differences may be attributed to the type of calorie (fat, sugars, proteins) ingested as opposed to the quantity.

So much for finding the fountain of youth in dieting. This primate is going to enjoy some ice cream with fudge now…and sprinkles.

Source:

Austad SN. Ageing: Mixed results for dieting monkeys. Nature, August 29, 2012.

Maxmen A. Calorie restriction falters in the long run: Genetics and healthy diets matter more for longevity. Nature, August 29, 2012.

Mattison JA, Roth GS, Beasley TM, Tilmont EM, Handy AM, Herbert RL, Longo DL, Allison DB, Young JE, Bryant M, Barnard D, Ward WF, Qi W, Ingram DK, de Cabo R. Impact of caloric restriction on health and survival in rhesus monkeys from the NIA study. Nature. August 29, 2012. doi:10.1038/nature11432

Comments

  1. #1 Russell
    September 5, 2012

    Damn, I guess I’ll have some chocolate.

  2. #2 Enver
    September 6, 2012

    I hypothesize totally unscientifically but logically, diets are new age puppies of high incomers and will going to take down their owners…

  3. #3 Scott D
    http://www.reddoorsolutions.com
    September 7, 2012

    I found this quite interesting that more research does not go to diabetes in animals after this study.

    SD – Florida

  4. #4 Moses R
    Austin, TX
    October 8, 2012

    It seems that we are just quick as dismissing possible factors as we are about assuming causes from correlations. I don’t think that the analysis of a very few studies gives us the total picture. As Don Ingram says at the end of the article, “[He] looks forward to studies of how diet composition, rather than caloric intake, affects aging. “Is the human lifespan fixed?” he asks. “I still don’t believe that for a minute.”

  5. #5 John Peloquin
    November 10, 2012

    Actually, given how much I like to eat, I’m glad caloric restriction doesn’t appear to help with primates. I would like to see what the effects of intermittent fasting might be though.

  6. #6 L Nick
    December 1, 2012

    here is the story of Nasrendin and his donkey. Nasrendin decided one day, most likely prompted by stories in the bazaar about the longevity of Karagioz’s wife who was thin as a toothpick and easily 100, to train his donkey in the art of not eating much now that Nasrendin’s income had diminished. The first day everything went well. The donkey accepted the half that Nasrendin had to offer. The second day still all was well in the third ration, and so on untill the day Nasrendin walked into the stable only to find his poor donkey going by the name of Lazaros dead as doorknob. “Geez” cried Nasrendin “just at the moment that he was getting used to no food”. And no matter how long or loud Nasrendin cried for Lazaros to come out the donkey would not respond.