caloric restriction doesnt increase longevity in monkeys

[The.Fourth.Deviation.]

Just read a study that contradicts one by the national institute of aging, and found that CR diets don't improve longevity in monkeys, even though other studies show it helps mice and other animals live longer. Any improvements in monkeys were basically due to diet. You can Google the study if you are interested in the topic. I just thought I'd mention it since I remember some here trying CR

[otto9otto]

On Wednesday, August 29, 2012 5:38:08 PM UTC-7, The.Fourth.Deviation. wrote:

Just read a study that contradicts one by the national institute of aging, and found that CR diets don't improve longevity in monkeys, even though other studies show it helps mice and other animals live longer. Any improvements in monkeys were basically due to diet.  You can Google the study if you are interested in the topic. I just thought I'd mention it since I remember some here trying CR

A few thoughts: This sample size of monkeys was small (doing such studies with monkey is, after all, ethically questionable) and so the death of one from anesthesia skewed the results to cast calorie restriction in a bad light. (I have not looked deeply into the numbers, but I suspect this is the case.)

The researchers simply fed the standard monkey chow, which is designed to supply nutritional needs when consumed ad libitum, in significantly smaller portions. NOT GOOD! The chow was not optimized to supply adequate nutrition in smaller portions. People who are calorie restriction enthusiasts are careful to eat nutrient-dense foods and many make use of supplements. The term is Calorie Restriction with Optimal Nutrition, or CRON. There is even software that many use to make sure they are not making a nutritional mistake.

More thoughts from Paul McGlothin published at c...@lists.calorierestriction.org:

"Even if the CR'd monkeys ate perfect CR diets, though, I would be surprised if they would live any longer and would expect their lives would be significantly shorter than animals allowed to live in normal environments. Both monkey studies were of incarcerated animals? intelligent mammals made to live in small cages for a lifetime. I think this is downright cruel.

Have you ever heard of a prisoner who became a centenarian? The stress of incarceration is great. Personally, if I were faced with living in such an environment for my entire life, I would want to die early."

My own further thoughts: calorie restriction significantly slows cognitive decline (the main reason I am an enthusiast). I believe it is plausible that the more cognitively acute monkeys were MORE stressed by being imprisoned than the duller ad libitum counterparts.

I am NOT removing calorie restriction from the longevity section of my health file.  (http://bit.ly/M4nytr) 

[Gwern Branwen]

On Thu, Aug 30, 2012 at 7:21 PM, otto9otto <otto...@gmail.com> wrote:
> More thoughts from Paul McGlothin published at
> c...@lists.calorierestriction.org:
>
> "Even if the CR'd monkeys ate perfect CR diets, though, I would be surprised
> if they would live any longer and would expect their lives would be
> significantly shorter than animals allowed to live in normal environments.
> Both monkey studies were of incarcerated animals? intelligent mammals made
> to live in small cages for a lifetime. I think this is downright cruel.
>
> Have you ever heard of a prisoner who became a centenarian? The stress of
> incarceration is great. Personally, if I were faced with living in such an
> environment for my entire life, I would want to die early."

I don't particularly mean to pick on Paul here, because he's far from
alone in these rearguard attempts - but IMO, this is a great example
of motivated cognition on the part of CRers.

You didn't see any criticism like this of the 2009 study! No one said
in 2009, "how could these CR monkeys possibly be living longer than
the controls? I'm so surprised! I expected all their lives to be

significantly shorter than animals allowed to live in normal

environments. This monkey study was of incarcerated animals? I think
this is downright cruel." Of course not, because the results came out
the way they "should" (even if they had to screw with the mortality
numbers to do so).

Note what a fully general argument* Paul has given us. One could -
with equal justice - use this to say that every single CR and IF study
ever done of any mammal or organism higher than yeast is invalid
because the animals were being kept in lab confinement etc. Strangely,
no one has said this. I wonder why.

* http://wiki.lesswrong.com/wiki/Fully_general_counterargument

Incidentally, if you want to read the fulltext of this study:
http://dl.dropbox.com/u/85192141/2012-mattison.pdf

--
gwern
http://www.gwern.net

[☉]

On Aug 30, 6:47 pm, Gwern Branwen <gwe...@gmail.com> wrote:
> Note what a fully general argument* Paul has given us. One could -
> with equal justice - use this to say that every single CR and IF study
> ever done of any mammal or organism higher than yeast is invalid
> because the animals were being kept in lab confinement etc. Strangely,
> no one has said this. I wonder why.
>
> *http://wiki.lesswrong.com/wiki/Fully_general_counterargument

http://en.wikipedia.org/wiki/External_validity
http://en.wikipedia.org/wiki/Ecological_validity

Just some points others may want to keep in mind....

argumzio

[Paul]

I have been overwhelmed with Calorie Restriction Society and CR Way related activity and not able to post on this list for over a week. For those who would like to read my opinion the NIA study, take a look:Monkey Study -- A Decade of Calorie Restriction Research Erased.

 I am not going to get into a point counter point about the subject here, since it seems too off topic for this list. I will be glad to discuss it on CR Way or CR Society forums, since people are there to discuss calorie restriction related subjects. Here, I think discussion of CR should relate to topics about cognition.

Paul