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Paul McGlothin

Dr. George Roth Comments on calorie Restriction and NIA Monkey Study

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Many media reports were written about the NIA Rhesus Monkey study: "Impact of Caloric Restriction on Health and Survival in Rhesus Monkeys," which was reported in August 2012. The Society is fortunate that Dr. George Roth, one of the authors of the paper and one of the two founding members of the study, has joined the CR Society’s Scientific Advisory Council. Dr. Roth was kind enough to provide his own interpretation of the study and how he feels about the media coverage:

 

The Reuters piece was probably one of the most objective, following our Nature paper (note also that the CR Soc is prominently mentioned), as many of the others seemed to substantially misinterpret the implications of our findings. Unfortunately, however, even this article does not completely convey our full message. While "combining the findings from both the NIA and U Wisconsin studies" is mentioned at the beginning, Reuters should have included this concept with my comments near the end to say that,

 

"Both the NIA and U Wisc studies need to be considered together for proper interpretation. It is clear that the U Wisc "controls" differ from the U Wisc CR group and BOTH NIA groups, and are probably most like the general populations of developed countries.

 

Because we at NIA wanted to avoid the criticism leveled at many rodent CR studies that controls are overweight and sedentary, we specifically designed our dietary conditions to supply an adequate, but not OVERadequate, caloric intake.

 

The bottom line is that, for most people (who are more like the U Wisc controls), CR may indeed provide both health (BOTH studies agree on THIS) and longevity benefits.....and of course, most important.....more "healthy years."

 

 

We thank Dr. Roth for his comments and are honored to have him as a scientific adviser. Read more: Calorie Restriction and the NIA Monkey Study.

 

Paul McGlothin, VP Research

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While the Reuters piece is better than some, it still contains inaccurate comments about what calorie restriction even is. Consider this comment from Dr. Steven Austad:

 

 

“Comparing calorie restriction to what you think is a normal diet but is in fact an unhealthy diet with too much food and too much sucrose can trip you up," said Austad. "If you keep your control animals to a healthy weight, as the NIA did, a diet that produces extreme emaciation has no further effect on longevity."

 

 

“Extreme emaciation” is not Calorie restriction. This distorted viewpoint is based on some animal studies and tabloid media accounts rather than actual practice of human calorie restrictors. Long ago most human learned to disregard rigid comments from scientists insisting that calorie restriction requires limiting calorie by 30% or more limitation for life extension to happen.

 

 

In fact, excellent CR Studies of calorie restriction in humans have shown that limiting calories by only 11% is enough to extend lifespan. Consider:*Willcox BJ, Willcox DC, Todoriki H, Fujiyoshi A, Yano K, et al: Caloric Restriction, the Traditional Okinawan Diet, & Healthy Aging Annals of the N.Y. Academy of Sciences. 2007 Oct;1114:434-55.

 

Paul

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Guest Mike

I had a chance to read the actual paper in Nature -- very interesting study and indeed supportive of the idea that only very moderate CR (and probably more importantly a healthy diet!) is required to see essentially all the benefits of dietary interventions for aging, with 30% CR probably being overkill for primates and humans. However, the statement by the researcher indicating that most Americans or other people on Western diets would benefit form CR is NOT the same thing as saying that CR slows aging, per se. It seems like what we may be seeing is that the "control" groups in many of these CR studies should really be viewed as the treatment groups (i.e., overeating hurts longevity while keeping calories in check prevents premature death -- but there is no extra "starvation benefit"). I see the NIA study as the more scientifically helpful of the two, because they controlled for the tendency of animals to "eat themselves to death" (including humans) if left to their own devices.

 

More fundamentally, what we really need to know to determine if CR provides additional, positive benefits is the effect of CR on lean, fit individuals who are already on healthy diets. Do you see a significant benefit (practical, not just statistical) for all that trouble? The NIA study approximated this to some degree and the answer was that there is no indication of a large benefit - a conclusion in line with the idea that humans and primates (unlike rodents and other species studied in these types of experiments) are "equilibrium" species as opposed to "growth" species, so our metabolisms should, evoloutionarily speaking, already be pretty well tuned for longevity.

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I had a chance to read the actual paper in Nature -- very interesting study and indeed supportive of the idea that only very moderate CR (and probably more importantly a healthy diet!) is required to see essentially all the benefits of dietary interventions for aging, with 30% CR probably being overkill for primates and humans. However, the statement by the researcher indicating that most Americans or other people on Western diets would benefit form CR is NOT the same thing as saying that CR slows aging, per se. It seems like what we may be seeing is that the "control" groups in many of these CR studies should really be viewed as the treatment groups (i.e., overeating hurts longevity while keeping calories in check prevents premature death -- but there is no extra "starvation benefit"). I see the NIA study as the more scientifically helpful of the two, because they controlled for the tendency of animals to "eat themselves to death" (including humans) if left to their own devices.

 

More fundamentally, what we really need to know to determine if CR provides additional, positive benefits is the effect of CR on lean, fit individuals who are already on healthy diets. Do you see a significant benefit (practical, not just statistical) for all that trouble? The NIA study approximated this to some degree and the answer was that there is no indication of a large benefit - a conclusion in line with the idea that humans and primates (unlike rodents and other species studied in these types of experiments) are "equilibrium" species as opposed to "growth" species, so our metabolisms should, evolutionarily speaking, already be pretty well tuned for longevity.

 

Hi Mike,

 

I am so glad you stopped by. Thanks for your comments.

 

I would not place too much stock on the conclusions of the rhesus monkey studies. There are a lot of variables that need to be worked out, before the studies can be considered very applicable to humans. You can find out more about that here : Calorie Restriction and the NIA Monkey study.

I must add that some of the senior researchers in the NIA study are wonderful to work with. We are going to have a scientific summit where the human and primate studies will be discussed and possibly integrated. This is being organized now.

 

As to whether or not it is worth it to go to the trouble to follow a CR lifestyle, the answer is an unequivocal yes. Participants in the human studies ( some of which have not been reported yet) show extraordinary health results -- functionality leaps forward and if you look carefully at Okinawan study I provided, just modest CR of only 11% produces significant benefits.

 

You make a good observation that primates and humans are not a "growth" species. And indeed mice are perhaps more of a growth species than humans. However, I spend a lot of my time thinking about how to safely slow growth among CR'd humans and thus preserve DNA Integrity and the health of the adult stem cell population. The results are extraordinary, with many achieving a level of functionality and health they did not dream possible. This is far different than following a "pretty good" diet.

"

Please do not use the word "starvation" when describing CR. Calorie restriction is a cell signaling diet that preserves and body structure rather than emaciating it like starvation would. Those who think very low body weight is better to practice CR are misguided.

 

Soon we will announce a new human study, DNA HACR, that looks at CR along with many other variable that are known to affect healthspan. Please watch for the details, which will explain a lot more of what I mention here.

 

Must run to a teleconference.

 

Wishing you extraordinary health,

 

Paul

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Guest Mike

Thanks Paul - I am in full agreement that the data clearly show improved health from a moderate (~10%) reduction from ad libidium - this is apparent in almost all organisms and in human studies. I expect further research will turn up even more good stuff in that regard. My statement was more directed at the expected longevity benefits - people practicing moderate CR (~10%) will most certainty be healther than those who eat as much as they want; however, how many extra years this adds to the "tail" of the mortality distribution is still up for debate. Will practicing CR increase your life expectancy from 85 to 120? From what I've read, I doubt that will be the case; however, could it extend your vital years into your 90's - that seems much more likely and it is the reason I practice a moderate CR and get in some exercise...both of which are known to significantly extend healthspan.

 

Again, thanks for your thoughtful response. I too am looking forward to the combined study of the Rhesus monkey studies, especially given their differing results.

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Guest elsie

The media articles seem to dismiss calorie restriction. I am a food addict, and so of course the anit-CR articles were probably meant to satisfy people like me. The difference is that I have tried fasting and calorie restriction, and although I love food, and I spend a great deal of money on food, I know that I felt the most at peace and physically healthy when I was either fasting or on a calorie restricted diet (I could only do it for a few months).

 

Although I have not been able to overcome my food addiction, my experiences convinced me of the benefits of calorie restriction, that I read the sensational media articles "calorie restriction doesn't work" with a great deal of skepticism. My guess is that these articles were funded by someone in the food industry. Of course, I would love to believe that I can keep eating and it will have no ill effect on my health, but I know it is killing me. I truly believe that what the CRON society is doing is correct, but I think you will face much resistance from food corporations. I am a food addict and it is making me sick, but I cannot stop. Please keep up the good work and hopefully some day the media will listen and stop trying to brainwash us to keep eating junk food.

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The media articles seem to dismiss calorie restriction. I am a food addict, and so of course the anit-CR articles were probably meant to satisfy people like me. The difference is that I have tried fasting and calorie restriction, and although I love food, and I spend a great deal of money on food, I know that I felt the most at peace and physically healthy when I was either fasting or on a calorie restricted diet (I could only do it for a few months).

 

Although I have not been able to overcome my food addiction, my experiences convinced me of the benefits of calorie restriction, that I read the sensational media articles "calorie restriction doesn't work" with a great deal of skepticism. My guess is that these articles were funded by someone in the food industry. Of course, I would love to believe that I can keep eating and it will have no ill effect on my health, but I know it is killing me. I truly believe that what the CRON society is doing is correct, but I think you will face much resistance from food corporations. I am a food addict and it is making me sick, but I cannot stop. Please keep up the good work and hopefully some day the media will listen and stop trying to brainwash us to keep eating junk food.

 

Thanks for your really honest comments, Elsie. I know for a fact that many food companies work hard to foster addiction to their products. The great book by David Kessler, the End of Overeating is worth a read in this regard. This video might give you some ideas about how to overcome your food addiction: The Other Side -- Chronic Calorie Restriction for Healthy Living. Being so courageously honest like you are is a good start.

 

Good luck and good health,

 

Paul

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