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Dean Pomerleau

We're (kinda) Famous! Dr. Greger on CR vs. Plant-based Diet

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Dr. Greger has authored an article today for the very popular health & wellness website Care2 titled How Does Obesity Increases Cancer Risk?

 

The interesting part is that he focuses on the cancer promoting effects of IGF-1, and uses data from Luigi Fontana's studies (particularly [1]) of some of us long-term CR practitioners. He also mentions the CR Society by name in the article! Unfortunately, he doesn't include a link to the CR Society website  :mellow:, but I've included one in the comments.

 

Here are the relevant passages:

 

<snip>

 

The only dietary group that comes close to the recommended BMI of 21 to 23 were those eating strictly plant-based diets, so maybe it’s the weight loss that did it [i.e. reduced IGF-1 - DP].

 

To put that to the test, we’d have to find a group of people that eat meat, but are still as slim as vegans. And that’s what researchers did—long-distance endurance runners, running an average of 48 miles a week for 21 years were as slim as vegans. If we run 50,000 miles we too can maintain a BMI of even a raw vegan. So what did they find?

 

If we look at blood concentrations of cancer risk factors among the groups of study subjects, we see that only the vegans had significantly lower levels of IGF-1. That makes sense given the role animal protein plays in boosting IGF-1 levels.

 

But the vegan group didn’t just eat less animal protein, they ate fewer calories. And in rodents at least, caloric restriction alone reduces IGF-1 levels. So maybe low IGF-1 among vegans isn’t due to their slim figures, but maybe the drop in IGF-1 in vegans is effectively due to their unintentional calorie restriction? So we’d have to compare vegans to people practicing severe calorie restriction.

 

To do this, the researchers recruited vegans from the St. Louis Vegetarian Society, and went to the Calorie Restriction Society to find folks practicing severe caloric restriction. What did they find?

 

Only the vegan group got a significant drop in IGF-1. These findings demonstrate that, unlike in rodents, long-term severe caloric restriction in humans does not reduce the level of this cancer-promoting hormone. It’s not how many calories we eat, but the protein intake that may be the key determinant of circulating IGF-1 levels in humans, and so reduced protein intake may become an important component of anti-cancer and anti-aging dietary interventions.

 

The discussion of vegans having low IGF-1, but not the omnivorous (or at least high protein) CR practitioners, comes from the Fontana study [1], which we've discussed many times before.

 

What's nice to see is that (for once) Dr. Greger doesn't (directly) promote a plant-based diets in his final analysis. Instead he focuses on the importance of keeping protein intake low as a potential key for preventing cancer.  What he doesn't mention is that in [1], when the CR practitioners reduced protein from 1.67 g/kg body weight to 0.95 g/kg body weight, their IGF-1 level dropped a lot.

 

This is one of the main reasons that many of us changed from a relatively high protein CR diet that we practiced in the early 2000s to the relatively low protein CR diet that we practice today, and why (I presume) Michael Rae modified the Megamuffin 2.0 recipe, with 28% of calories from protein to the Megamuffin 3.0 recipe, with only 15% of calories from protein.

 

--Dean

-------------

[1] Aging Cell. 2008 Oct;7(5):681-7.

Long-term effects of calorie or protein restriction on serum IGF-1 and IGFBP-3
concentration in humans.

Fontana L(1), Weiss EP, Villareal DT, Klein S, Holloszy JO.

Author information:
(1)Division of Geriatrics & Nutritional Sciences, Washington University School of
Medicine, St Louis, MO 63110, USA. lfontana@dom.wustl.edu

Comment in
Aging Cell. 2009 Apr;8(2):214; author reply 215.

Reduced function mutations in the insulin/IGF-I signaling pathway increase
maximal lifespan and health span in many species. Calorie restriction (CR)
decreases serum IGF-1 concentration by ~40%, protects against cancer and slows
aging in rodents. However, the long-term effects of CR with adequate nutrition on
circulating IGF-1 levels in humans are unknown. Here we report data from two
long-term CR studies (1 and 6 years) showing that severe CR without malnutrition
did not change IGF-1 and IGF-1 : IGFBP-3 ratio levels in humans. In contrast,
total and free IGF-1 concentrations were significantly lower in moderately
protein-restricted individuals. Reducing protein intake from an average of 1.67 g
kg(-1) of body weight per day to 0.95 g kg(-1) of body weight per day for 3 weeks
in six volunteers practicing CR resulted in a reduction in serum IGF-1 from 194
ng mL(-1) to 152 ng mL(-1). These findings demonstrate that, unlike in rodents,
long-term severe CR does not reduce serum IGF-1 concentration and IGF-1 : IGFBP-3
ratio in humans. In addition, our data provide evidence that protein intake is a
key determinant of circulating IGF-1 levels in humans, and suggest that reduced
protein intake may become an important component of anticancer and anti-aging
dietary interventions.

PMCID: PMC2673798
PMID: 18843793

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But the vegan group didn’t just eat less animal protein, they ate fewer calories. And in rodents at least, caloric restriction alone reduces IGF-1 levels. So maybe low IGF-1 among vegans isn’t due to their slim figures, but maybe the drop in IGF-1 in vegans is effectively due to their unintentional calorie restriction? So we’d have to compare vegans to people practicing severe calorie restriction.

 

To do this, the researchers recruited vegans from the St. Louis Vegetarian Society, and went to the Calorie Restriction Society to find folks practicing severe caloric restriction. What did they find?

 

Only the vegan group got a significant drop in IGF-1. These findings demonstrate that, unlike in rodents, long-term severe caloric restriction in humans does not reduce the level of this cancer-promoting hormone. It’s not how many calories we eat, but the protein intake that may be the key determinant of circulating IGF-1 levels in humans, and so reduced protein intake may become an important component of anti-cancer and anti-aging dietary interventions.

 

Um, no. He's just told us that "the vegan group didn’t just eat less animal protein, they ate fewer calories." The fact that CR folk eating high-protein diets didn't exhibit a drop in IGF-1 doesn't show you that reducing protein intake alone lowers IGF-1: it shows you that reducing Calories alone won't do it, without concomitantly lowering protein intake. And as Dean rightly notes (and as Greger ought to know, if he's done enough research to come across hist study), even moderately lowering protein intake in a CR context causes significant drops in IGF-1.

 

What's nice to see is that (for once) Dr. Greger doesn't (directly) promote a plant-based diets in his final analysis. Instead he focuses on the importance of keeping protein intake low as a potential key for preventing cancer.

It merits saying, tho', that plant-based proteins don't support IGF-1 levels on a gram-for-gram basis as much as animal proteins do.

 

This is one of the main reasons that many of us changed from a relatively high protein CR diet that we practiced in the early 2000s to the relatively low protein CR diet that we practice today, and why (I presume) Michael Rae modified the Megamuffin 2.0 recipe, with 28% of calories from protein to the Megamuffin 3.0 recipe, with only 15% of calories from protein.

 

Indeed (tho' not really "early 2000s:" Fontana's paper (your (1) was published in 2008. I see reference in my email to Paul having made this shift no later than 2007, based on self-testing; I'm not sure exactly when he made the shift, but I doubt it was prior to 2005 and doubt even more that many followed his lead until the Fontana paper). See my discussion of lowering protein intake for CR for discussion of why I ultimately switched from advocating a high- to a moderate (RDAish)-protein diet for CR, on this and responses to some then-common counterarguments.

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This is one of the main reasons that many of us changed from a relatively high protein CR diet that we practiced in the early 2000s to the relatively low protein CR diet that we practice today.

 

Indeed (tho' not really "early 2000s:" ...

Point well taken. Thanks for the historic context.

 

I set my vegan, high-ish protein diet (including lots of plant protein isolates) in the "early 2000s" and then went on autopilot for a few years, largely losing touch with my CR friends. :-(

 

I just figured you guys must have woken up to the downsides of too much protein while I wasn't looking sometime around the mid-2000s :-).

 

But apparently I wasn't that late to the low-protein party when I resurfaced and changed my misguided ways!

 

--Dean

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Out of curiosity, why would you have cut your protein intake in a period prior to the Fontana paper, and when you were unplugged from the CR Society discussions and indeed not really very focused on life extension? I trust it wasn't the Chiina Study ;) .

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Out of curiosity, why would you have cut your protein intake in a period prior to the Fontana paper, and when you were unplugged from the CR Society discussions and indeed not really very focused on life extension? I trust it wasn't the Chiina Study ;) .

Hmmm...

 

Your question "why would you have cut your protein intake before the Fontana study when you were out of the loop?" can be interpreted in either of two ways. The first, less plausible, is as a hypothetical. I.e. what would have caused you to cut protein, whether you did or not?

 

I suspect you are asking when actually DID I cut protein, and why. At least that is how I'll interprete your question.

 

First off, I went vegan in 2004, meaning I was inclined towards less protein, and less highly-assimilatable protein, since around then. The reason for the switch from omnivore to vegetarian (circa 2002) and then from vegetarian to vegan (in 2004) was mostly ethical. I continued to eat relatively higher protein than I do now during those early vegan years, via supplementing with plant-based protein isolates (pea, rice, soy & hemp protein) as mentioned above.

 

The best data I have from that era, available at my VERY OLD personal website here:

 

http://deanpomerleau.tripod.com/Dean_regime/Dean_diet/meal.htm

 

is that in early 2005, I was eating a diet of around 2000 kcal/day with a macronutrient ratio of 20:53:27 P:C:F. This is lower protein (and fat) than the Zone-ish macro ratios that were popular back then (30:40:40), but not as low as the 12-14% protein that I (and I believe you) eat these days, as a result of insights about the downsides of extra protein.

 

Exactly when I dropped lower than 20% protein is hard to say. In email to Luigi for a human CR study visit to WUSTL in 2008, I was still eating that same diet above with 20% protein. So it was sometime between 2008 and 2012, at which point I have definitive evidence (via CRON-O-Meter) that I was eating 14% protein (around 14:56:30 PCF).

 

Subsequent to that, in early 2013, I shifted from around 14:56:30 PCF to 13:71:16 PCF - i.e. the high-carb, low-fat, mostly raw vegan diet that I eat today.

 

Finally, it was definitely NOT the China Study that motivated any of my dietary changes, although I admire the work of Collin Campbell, despite the way he and the other four "horseman of the vegan apocalypse" (i.e. John McDougall, Neal Bernard, Dean Ornish, Michael Greger) tend to oversell the benefits of a low-protein, low-fat, strictly plant-based diet. ;-)

 

Finally, thanks for prompting me to do this bit of "diet archeology". It's nice to have a better picture of one's dietary evolution over the years.

 

--Dean

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Out of curiosity, why would you have cut your protein intake in a period prior to the Fontana paper, and when you were unplugged from the CR Society discussions and indeed not really very focused on life extension? I trust it wasn't the Chiina Study ;) .

Hmmm...

 

Your question "why would you have cut your protein intake before the Fontana study when you were out of the loop?" can be interpreted in either of two ways. The first, less plausible, is as a hypothetical. I.e. what would have caused you to cut protein, whether you did or not? I suspect you are asking when actually DID I cut protein, and why.

I suppose that the former is a grammatically possible reading of the question, but it would be a bizarre one to ask, and too indefinite to meaningfully answer. I meant, of course, the latter.

 

First off, I went vegan in 2004, meaning I was inclined towards less protein, and less highly-assimilatable protein, since around then.

Er, but why did going vegan incline you to eat less protein?

 

I continued to eat relatively higher protein than I do now during those early vegan years, via supplementing with plant-based protein isolates [...] [by] early 2005, I was eating a diet of around 2000 kcal/day with a macronutrient ratio of 20:53:27 P:C:F. This is lower protein (and fat) than the Zone-ish macro ratios that were popular back then (30:40:40), but not as low as the 12-14% protein that I (and I believe you) eat these days, as a result of insights about the downsides of extra protein.

 

Exactly when I dropped lower than 20% protein is hard to say. In email to Luigi for a human CR study visit to WUSTL in 2008, I was still eating that same diet above with 20% protein. So it was sometime between 2008 and 2012, at which point I have definitive evidence (via CRON-O-Meter) that I was eating 14% protein (around 14:56:30 PCF).

Right, but at that point there was an evidence base that I've already noted and of which most informed CR practitioners are aware. Many CR practitioners dropped their protein intake in the years subsequent to that finding, and it makes some sense, at least, that you would have at least considered dropping your protein intake lower at that point — tho' I wouldn't have advised you to do so: as I noted here, your IGF-1 levels were already reasonably low from 6-27-2001 thru' 07-25-2003 (aside from an outlier test at 11-19-2002 — and we don't have your IGFBP3 for that or any of your other dates), and then there is a data gap from July 2003 (at which point they were once again quite respectably low) until 2012, by which point your IGF-1 levels had fallen precipitously to a level that I would think risky.

 

The reason why the Fontana study suggests one might want to consider eating less protein is because it might be needed for CR folk to lower their bioactive IGF-1: since yours was already plenty low enough at 20% vegan protein, I would have left well enough alone.

 

And, actually, I did — and went one step further (which goes to your "and I believe you"): as I've noted before, even at ≈80 g protein and 16% of energy from mostly vegetal protein, my free and total IGF-1 levels were too low (and I attribute some negative health effects thereto), and I've subsequently bumped that up to 20% protein, with the extra protein being either dairy or more highly-absorbable vegetal sources (tho' I have a hard time titrating my protein intake to get a consistent, agreeable IGF-1 profile).

 

But, IAC, that still leaves my original question unanswered, which is why would you have cut your protein intake in a period prior to the Fontana finding.

 

Subsequent to that, in early 2013, I shifted from around 14:56:30 PCF to 13:71:16 PCF - i.e. the high-carb, low-fat, mostly raw vegan diet that I eat today.

That, of course, I consider a bit nuts — but we can agree to disagree, and your nutrition is overall excellent, your blood tests mostly look good, and AFAIK you're objectively and subjectively quite healthy.

 

Finally, it was definitely NOT the China Study that motivated any of my dietary changes, although I admire the work of Collin Campbell, despite the way he and the other four "horseman of the vegan apocalypse" (i.e. John McDougall, Neal Bernard, Dean Ornish, Michael Greger) tend to oversell the benefits of a low-protein, low-fat, strictly plant-based diet. ;-)

 

The issue with the China Study is not that Campbell oversells veganism (though he uses it to do that): it's that the study itself is ecological garbage. The other "horsemen" make bad arguments to varying degrees, but in a lot of cases that's drawing incorrect or misleading conclusions from misinterpretation of perfectly-good studies. By contrast, the China Study just shouldn't enter into discussion aside from as a paradigmatic example of the kind of evidence against which people need to train their brains to avoid being seduced.

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But, IAC, that still leaves my original question unanswered, which is why would you have cut your protein intake in a period prior to the Fontana finding.

 

Michael,

 

I can't say for sure, but I suspect my motivation was not so much to lower dietary protein per se, but to reduce my reliance on highly-processed plant protein isolates, in favor of less adulterated sources of protein. While I continued to consume such isolates even after dropping my protein to 20% of calories, they weren't quite as large a part of my diet. Since then, I've eliminated protein isolates entirely, and my protein percent of calories dropped further to where it is now (~14%).

 

Your concern over my very low IGF-1 is (once again), respectfully noted. As you mention, I feel great and my blood tests are otherwise pretty solid. But I readily admit this is weak evidence that my metabolic state will be healthy long-term...  

 

I'm curious, what are the "negative health effects" you allude to when your protein / IGF-1 is too low?

 

--Dean

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So what Greger did not consider is that by now most (?) of the Cr-people have switched to plant-based/low-protein in addition to their calorie restriction and therefore there really is no useful long-term data on humans to make the comparison between pb-cr vs. Pb-only.

 

Though there was a study on Rhesus Monkeys. Not a rodent and plant-based by default, one of the cr group still alive after 42 years when average life span of his species is 20-25 years.

 

So definitely gonna stick with cr.

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