Monday, April 9, 2012

Harvard Meat Study

On Monday, March 12, 2012, the Archives of Internal Medicine published online "Red Meat Consumption and Mortality: Results From 2 Prospective Cohort Studies," a study done by researchers from the Harvard School of Public Health.  This study found that eating even one serving daily of red meat increased total mortality and risk of mortality from cardiovascular disease and cancer.

The researchers carefully controlled for intakes of total energy, whole grains, fruits, and vegetables; age; body mass index; race (white or nonwhite); smoking status; alcohol intake; physical activity level; multivitamin use; aspirin use; family history of diabetes mellitus, myocardial infarction, or cancer; and baseline history of diabetes mellitus, hypertension, or hypercholesterolemia. In women, they also adjusted the data for postmenopausal status and menopausal hormone use.

Some in the cattle industry have questioned the validity of the food frequency questionnaires used in this type of study (here).  The authors of the study responded:

"However, all the questionnaires used in this study have been validated against multiple-day food records—at least 14 days during a year—and have been found to be acceptable in terms of validation and reproducibility.
"Second, although there [are individual] day-to-day variations in food consumption, people are generally eating in a pattern that can be captured by the questionnaire. We were interested in between-person variation[s], and we were comparing people who eat a high amount of red meat to those who eat a low amount of red meat. Because we repeated the measurements every four years, the cumulative average used in the analysis represents a long-term dietary pattern. That is a strength of this study, because many other studies may have only a single measure at baseline.
"Last, but most importantly, the measurement error generally tends to attenuate the association, and if we corrected the measurement error using some statistical methods, the associations were much stronger!"  [emphasis added]

Some have responded to this by claiming that "correlation doesn't equal causation" (as if the Harvard researchers don't realize this), or that the results only apply to consumption of conventional meat, not grass-finished.

Such a response ignores two important facts:

1) This study is only one among hundreds finding an association between red meat consumption and increased mortality from heart disease and cancer. 

2) Basic research has shown that these hazards arise from components that occur in meat from grass-fed animals at levels equal to or greater than levels found in meat from grain-fed animals.  

The following provide examples of the large number of studies finding positive associations between consumption of red meat and adverse health outcomes:

Meat consumption and colorectal cancer risk: Dose-response meta-analysis of epidemiological studies

Meat consumption and risk of colorectal cancer:  A meta-analysis of prospective studies 

Processed meat consumption and stomach cancer risk meta-analysis

Meat consumption and the risk of type 2 diabetes meta-analysis

Meat consumption and prostate cancer risk

Thus, this new study is not some isolated, rare, unusual finding.  It resonates with a large body of corroborating epidemiological evidence finding a positive association between red meat consumption and risk of or mortality from disease.  It adds to that growing body of evidence. 

Of course, "correlation does not prove causation," so some scientists have taken the next step required, doing research to find out if there are any plausible mechanisms by which consumption of meat could increase the risk of mortality. 

So far, researchers have found that a number of components of red meat have biological effects providing plausible mechanisms by which diets rich in meat could increase the risk of chronic diseases and mortality.  The suspect components include animal protein, cholesterol, arachidonic acid, heme iron, and Neu5Cg sialic acid, all of which naturally occur in red meat.  Further, the concentration of these components of meat is not markedly affected by feeding or pharmaceutical strategy used in raising the animals; meat from grass-fattened animals has practically the same amount of these components as meat from grain-fattened animals.

Animal Protein

Animal protein typically forms a larger proportion of lean grass-fed than conventional fatty meat, and promotes increases in IGF-1 levels, which appears involved in promotion of breast, colon, and prostate cancers.

High animal protein intake raises serum IGF-1 levels. [Full text]

IGF-1 has roles in growth promotion and carcinogenesis. [Abstract]

Elevated IGF-1 levels were associated with a 49% increased risk of prostate cancer and a 65% increased risk of premenopausal breast cancer.  [Abstract]

Elevated IGF-1 levels are associated with increased risk of prostate cancer, lung cancer, colorectal cancer, and premenopausal breast cancer. [Abstract]  

Dietary Cholesterol

Starting with a zero cholesterol diet, adding small increments of dietary cholesterol raises serum cholesterol levels, in a dose-response fashion.[Full text]

Elevated serum cholesterol increases the risk for cardiovascular disease. [National Cholesterol Education Program]

Elevated serum cholesterol increases risk of ischemic stroke in the general Japanese population.[Abstract]

Mice fed a high fat, high cholesterol diet and showing elevated serum cholesterol have increased mammary tumor growth and metastases compared to controls. [Abstract]

Emerging evidence indicates that oxidized cholesterol plays an important role in the angiogenesis process that supports tumor growth. [Abstract]  

The more unnecessary LDL cholesterol in the blood, the more likely there will be oxidized cholesterol in the blood.

Individuals with elevated serum cholesterol found to have a 35% increased prostate cancer risk.[Abstract]

Cholesterol-depletion of breast and prostate cancer cell lines induces apoptosis  whereas cholesterol-enrichment via elevated serum cholesterol (due to diet) supports tumor growth and progression.[Abstract, Full Text]

Elevated LDL positively correlates with increased risk of advanced stage colon cancer.[Abstract]

Patients with colon adenomas, the precursors of colon cancer, have elevated LDL.[Abstract]

Patients with distant metastases of colorectal cancer have significantly elevated serum cholesterol levels compared to those without metastases. "Elevated serum lipid levels may facilitate the development of distant metastasis in CRC [colorectal cancer] patients."[Abstract

Heme Iron, Arachidonic Acid, HCAs, PHAs, and Neu5Gc

Heme iron, a form of iron found at the highest levels in red meats. I discussed some of the evidence linking iron intake and levels to inflammatory diseases (including heart disease and cancer) in this post.

Arachidonic acid, which occurs in meat from grass-fed animals at levels equal to or greater than found in meat from grain-fed animals, and is involved in cancer promotion, which I discussed in this post.

Neu5Gc, a type of sialic acid produced by non-human mammals but not by humans, which enters humans through consumption of mammalian meat and milk, is incorporated into epithelial and endothelial tissues, incites an auto-immune response and inflammation in those tissues, and has been found concentrated in malignant tumors (full text).  

Of interest, this paper on Neu5Gc includes the following passage:

"Although earlier studies claimed the absence of Neu5Gc from normal human tissues, we showed thatit is also present in smaller amounts in normal human epithelial and endothelial cells in vivo (Tangvoranuntakul et al. 2003). Furthermore, we recently demonstrated that mice with a human-likedefect in the CMAH gene had no detectable Neu5Gc (Hedlund et al. 2007), effectively ruling out an alternate mammalian pathway for synthesis. This paradox is explained by our finding that humans can metabolically incorporate Neu5Gc via oral intake (Tangvoranuntakul et al. 2003). We have therefore suggested that the well-known epidemiological association of human cancers with consumption of red meat and milk (which happen to be the richest dietary sources of Neu5Gc) (Rose et al. 1986; Norat et al. 2002; Lewin et al. 2006) might be related to this unusual metabolic accumulation. Here, we have demonstrated another required component for this hypothesis – circulating antibodies that can recognize Neu5Gc on human tissues and can potentially generate chronic inflammation. To our knowledge, this is the first example wherein a nonhuman molecule becomes metabolically and covalently incorporated onto human cell surfaces, even in the face of an immune response against it. Further studies are needed to firmly establish a link between Neu5Gc expression in tumors and anti-Neu5Gc in the pathogenesis of carcinomas."[emphasis added]
This passage illustrates that the epidemiological association of human cancers with consumption of red meat and milk is "well-known" among scientists and that they have moved beyond questioning the association (since it is scientifically well established) to elucidating the mechanisms responsible for this association, in this case Neu5Gc, the first nonhuman molecule proven to become part of human cell surfaces despite an immune response against it.

I first learned about Neu5Gc from this video by Plant Positive:

Cooking meat at high temperatures, particularly over open flames, produces heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) which are carcinogenic.   These will form in meat cooked at high temperatures regardless of how the source animal was fed.    The National Cancer Institute says "numerous epidemiologic studies have used detailed questionnaires to examine participants’ meat consumption and meat cooking methods to estimate HCA and PAH exposures. Researchers found that high consumption of well-done, fried, or barbecued meats was associated with increased risks of colorectal (14), pancreatic (15, 16), and prostate (17, 18) cancer."

Protein, cholesterol, iron, arachidonic acid, and Neu5Gc all occur naturally in meat, and HCAs and PAHs form in meat cooked at high temperatures, regardless of the feeding or pharmaceutical strategy used to raise the animals from which the meat is taken.  

The studies I cited above only provide a small sampling of the laboratory data providing evidence of plausible mechanisms by which an excessive consumption of meat could increase one's risk of mortality.  Epidemiological research generated both the lipid hypothesis and the hypothesis that red meat increases mortality risk, but we now have much stronger data to support these hypotheses. 

We have evidence for specific mechanisms by which these naturally occuring substances can initiate (HCAs or PAHs) or promote (protein, cholesterol, iron, arachidonic acid, and Neu5Gc) fatal diseases, so only someone ignoring or ignorant of the above data could argue that the association of increased risks of mortality from cancer and heart disease apply only to people eating meat from grain-fed or drug-treated animals, or that the epidemiological associations have no plausible physiological basis.


healthy-longevity said...
This comment has been removed by the author.
Jimmy Gee said...

Further and further into left field.

healthy-longevity said...

The Harvard researchers point out in virtually all the papers they publish on these cohorts, as they did in this one that “Because of the prospective study design, any measurement errors of meat intake are independent of study outcome ascertainment and, there-fore, are likely to attenuate the associations toward the null.” Skeptics use the limitation of dietary measurement error as an excuse to claim that a study is flawed and uninformative, but ignore that this would result in the regression dilution bias which is more likely to underestimate the true relationship. For example the researchers found in the sensitivity analysis that accounted for measurement error in diet, the association between 1-serving-per-day increase in total red meat intake and all-cause mortality increased to 25% and 83% in the HPFS and NHS respectively.

healthy-longevity said...

Here are some more import studies that may not have been covered:
Compared to less than 1 serving per week, 2 or more servings of meat increased the risk of colorectal cancer in a prospective study of over 2.24 million Korean adults.

Association between meat and 13 different cancers in a large case control in Uruguay where hormones are banned by law and livestock are primarily grass fed

2011 Meta-analysis of the association between both fresh and processed meat and the risk of colorectal cancer

2011 Review of epidemiological studies and clinical trials showing an association between dietary heme and risk of colorectal cancer

2011 Meta-analysis of the association between red and processed meat and the risk of bladder cancer

healthy-longevity said...

2012 Meta-analysis of the association between red and processed meat and the risk of pancreatic cancer

2012 Pooled analysis of the association between red and processed meat intake and the risk head and neck cancer

Meat and mortality in the large NIH-AARP Diet and Health Study

Does low meat consumption increase life expectancy in humans?

Red meat consumption and risk of heart failure in male physicians

Red meat consumption during adolescence and risk of premenopausal breast cancer

Jimmy Gee said...

Need to be careful- percentages can be very misleading.

nothing91 said...

Ah, you knew as soon as that "study" came out that some gold from Don would follow. I'm just surprised it took so long.

Do you think he missed that the top group of red meat eaters had a lower incidence of high cholesterol than the bottom group? Or that they smoked more, drank more, and exercised less? :-)

nothing91 said...


"Like some others, you want to draw conclusions from raw data, without the multivariate analysis required for isolating the effect of meat consumption from the potential confounders that you mentioned."

I'm so glad you brought up multivariate analysis. The authors of the study seem to be poor at it. I think you'll really enjoy this:

Don said...


Did you miss that the authors controlled for elevated cholesterol levels, smoking, alcohol use, and physical activity level, in order to determine the relation of meat to mortality independent of these factors?

Like some others, you want to draw conclusions from raw data, without the multivariate analysis required for isolating the effect of meat consumption from the potential confounders that you mentioned.

Did you miss all the other studies that I and healthy-longevity listed showing increased risk of mortality or disease from meat consumption in multiple nations, not just the U.S.?

Did you ignore all the studies I linked to showing specific mechanisms by which high meat consumption may increase disease or mortality?

Do you really think that if the raw data from one group of heavy meat eaters in one study appears to have a lower incidence of hypercholesterolemia, that this tells us something about how meat consumption affects blood cholesterol?

Don said...


Ned did not use the entire dataset used by the Harvard authors, he used only 10 datapoints from the tables they provided.

In the comments section, Ned himself states: "Mind you, there is massive collinearity in this N=10 dataset that I used, so the results in this post are meant to raise questions, as opposed to being a definitive revision of the results reported by the authors."

How could it be a revision when he doesn't even have access to the full set of data?

Again, all studies have some flaws, that's why the community does lots of studies and looks for trends and predominance of evidence.

nothing91 said...


He also says in the comments that controlling for sex (Ned did, the study didn't) appears to be what makes the difference. Odd that the authors didn't do this -- maybe because it ruined their "assocation". (Do you have another theory as to why a multivariate analysis on the quintile data would show the opposite effect as the individual data?)

The only trend we can deduce from these epidemiological meat studies is that people who eat more meat tend to have less healthy lifestyles than those who eat less, in just about every way imaginable. To think that it's possible to control for everything (thereby isolating one variable) is foolish. Researchers like Willett like to think they can pull it off because the "results" (even tiny results, in this study's case) enhance their careers. Readers like us, however, are supposed to know better. :-)

Frank said...


So, in all objectivity, in the face of the overwhelming evidence from epidemiological, fundamental and experimental research, which all points to the same direction (meat is less than ideal as a food choice) what is your explanation for all these negative results? Conspiracy? Bad science? Seriously, how can you explain away all of these evidences, logically?

On a fundamental level, what do you think of

1) the AGEs products and the amine products formed while the cooking of meat
2) the less than ideal fatty acids profile (we can argue as much as we want about the quality of the evidence but so far the science is clear : SFA reduce insulin sensitivity, it raises cholesterol, it creates inflammation post-prandialy, enhance LDL oxidation)
3) the high contaminants content of meat?

And, out of curiosity, why do you defend meat so much? Why would it matter if meat is not good for health? Seriously?

Would you be able to accept it if vegan was the best way to eat? If not, then you are emotionnally engaged in this and are not considering the facts objectively, hence it is useless to argue with you.

If you tell me in all honesty that you can switch to vegan tomorrow if the science is clear, then I think you should really re-consider the science, and the first step would be to listen to the Primitive Nutrition video series.

Paleo has it wrong. We have never eat much animal product, we have a long history of plant-based nutrition, all of our closest species are omnivor with a high % of plant-based food, and modern science keep finding the same results: plants products are better than animal product. And all the science to prove this is presented in the nutrition primitive video, with all the logical fallacies and pseudoscience of the paleo mouvement. People would really do themselves a favor to listen to it objectively.

WoLong said...

It just amazes me that there are so many people who are smarter than Harvard researchers. But I guess people love conspiracy theories way more than science.

ICG said...

No comments on meat studies in particular, but siding with someone just they're a "Harvard researcher" is asinine. To wit,

And what about the problems in cancer research in general?

Truth be told, scientists aren't agenda-less robots. They can't help but take their presuppositions and biases into their studies. And since certain "studies" are much more likely to get juicy grants, well, draw your own conclusions.

Thomas Kuhn's work on scientific paradigms is just as appropriate now (if not more so) than it was hundreds of years ago.

Frank said...
This comment has been removed by the author.
Frank said...


I think we're all perfectly aware that researchers have their own bias, that science is not perfect, etc, etc.

This is why you always look at the whole body of evidence before coming to a conclusion. If you believe that every study out there is biased or poorly conducted, then you believe modern science is useless and we don't have much less to argue about, since all that will be left is anecdocte and opinions.

Second, i'd just like to point out that the exact same thing could be said about the study that are being used by these supporting paleo, so if we're going to use that logic, again, we can't get into a proper debate since we have no objective data to based our arguments on.

What should we do then? Find a guru that is being spoken the Truth from the Above and follow him?

Science is not perfect, but an imperfect science is better than no science at all.

This, obviously, holds true only if you have a good understanding of statistics, the scientific method and the physiology of the subject at hand, which frankly is not the case of most blog readers - and even most blog writer.

Frank said...

I'd just like to add that Paleo have much less scientific research, researchers, and belivers than mainstream nutrition have, so bias is much more likely to be present in the paleo world, with circular references being made much more often (always the same few book, author, blog are and few papers research are presented as evidence, whereas mainstream nutrition have tonz and tonz of different researchs, on different levels, and different researchers.

There is also not much money to be made by selling mainstream nutrition : nobody will buy a book that repeat the same thing. And as pointed out by Plant Positive, if you believe the big Pharma conspiracy, think about this : what would happens if the cholesterol hypothesis (I should write theory, since it's pretty much accepted) is true and that vegan really lower cholesterol by a lot? Well, Big Pharma would have not much drug to sell, would they? They have nothing to gain by pushing the vegan agenda. If they want to sell a lot of drugs, they are better off telling people to eat paleo.

ICG said...


Some fair points. I'm still sorting out the studies and have no dog in the meat fights (wow, that was a weird metaphor!).

As for Big Pharma, I don't think they care about nutrition. They know the masses will eat the SAD, which is worse than paleo or vegan. (The best versions of both paleo and vegan avoid refined sugars, processed foods, PUFAs, etc., so I think both will improve most people's health.)

Big Ag, Big Pharma and the gov't (who has lots of revolving doors between its regulators/officials and Big Ag/Pharma) are all fine with SAD while giving lip service to the food pyramid. Of course the pyramid is far from optimal, but that's another story.

Frank said...


I also think these are fair points. (i'm a meat eater, that adhered to the paleo, high fat high meat mouvement for 2 years but who came back exactly to where he started = high carbs, lower animal products, plant-based nutrition - and now i'm trying to lower animal product even more)

It's sad because it's very hard these days to have a construtive nutritional debate because people are way too emotionnally invested in the issue, and with internet, everyone seems to be thinking they are expert because they read a few blogs. The real expert are not even seen as the expert now, much usually the real expert are being seen as biased/incompetent/brainwashed.

I'M still listening to the Primitive Nutrition series right now and it's so damn right : Imagine, you have a guy like Tom Naughton, a comedian, critiquing top MD cardiovascular researcher which have spent their whole life studying cardiovascular diseases.

How more ridiculous can that be?

(and he does that using the appeal to authority, obviously)

I'm not saying that credential is bullet proof - there are some MD buying the Paleo and Low-carb, after all, but it's just too easy to call out people on something you have never really been invested in. And, again, in any case, we don't need appeal to authority here, the science is quite clear, and if I choose to be science-based, i'm limiting my consumption of animal product to a minimum.

Would people go to their mechanics and tell him how to do his job because they read on a website how to change their oil?

Would they tell an architect how to plan their house because they read house design magazine?

Only in nutrition and exercice science do we see regular joe thinking they outbright top researchers with years and years of education on a subject because they have read a book.

It's kind of ridiculous, if you ask me, and downright scary.

As for the pyramid, the SAD is not the pyramid, tho'. I think the pyramid is just fine, again, it goes with the science : high complex carb (there are tonz of gluten-free source of starch to choice from if that matter to anyone), moderate to low-fat, predominently PUFAs and MUFAs, mostly plant-based foods, avoid processed food, limiting cholesterol and SFAs... that's exactly the current scientific definition of an healthy diet.

Again, I'd send you to the Primitive Nutrition series for much more on the science behind that. Have you watch it?

Thanks for your open mind! It's refreshing to have someone considering what we say, even if it goes agaisnt their current beliefs.

healthy-longevity said...

In the Harvard studies, adjusting for heme iron from meat attenuated the risk between red meat and risk of type 2 diabetes and death from cardiovascular disease, suggesting a mechanism through which red meat increases the risk of mortality regardless of the farming practice. Here are some more studies in regards to the mechanisms of meat and an increased risk of mortality.

Heme Iron

Numerous tightly controlled metabolic ward studies with human participants have confirmed that heme iron from meat significantly increases the production of cancerous N-nitroso compounds (NOC) in the digestive tract.

A tightly controlled metabolic ward study with human participants found NOC arising from heme iron in meat forms DNA adducts in the colon, a risk factor for cancer.

Serum Cholesterol

A meta-analysis of 108 randomized controlled trials of various lipid modifying interventions found that lowering LDL cholesterol significantly decreased the risk of coronary heart disease and all-cause mortality, whereas modifying HDL provided no benefit after controlling for LDL cholesterol.

A Mendelian randomized control trial with over one million participants found that inheriting polymorphisms that are associated with life-long reduced LDL cholesterol, but not with other known risk factors, predicted a three-fold greater decrease in coronary heart disease per mmol/L lower LDL cholesterol than statins do in mid and late life.

Ornish et al. demonstrated in an intervention trial that lowering LDL was associated with increased telomerase activity, which in turn is associated with longevity.

The 40 year follow-up of the Whitehall study found that men with higher serum cholesterol were at greater risk of dying from prostate cancer.

Two large prospective studies with up to 37 years follow-up found that men with higher serum cholesterol were at greater risk of developing high-grade prostate cancer.

Dietary Cholesterol

Studies have shown that feeding dietary cholesterol to non-human primates can induce severe atherosclerosis, even when fed in small amounts.

Dietary cholesterol increases the susceptibility of LDL-C to oxidation, vascular inflammation, oxidative stress, and postprandial hyperlipemia and potentiates the harmful effects of saturated fat, impairs endothelial function, and increases cardiovascular events.

WoLong said...

I myself am a scientist (not in the field of health) and I can tell you that, as scientists, we get excited if our findings do not fall in line with conventional ones, sadly, too often these exciting findings are due to experimental errors or wrong interpretations due to insufficient knowledge.
Also, no funding agencies, whether government or private industry, dictate us to find the results they want. If we do not produce results they expected, they would be sad, ask us to repeat and eventually accept them. This may not happen to all funders, but these have been my experience.

nothing91 said...


"So, in all objectivity, in the face of the overwhelming evidence from epidemiological, fundamental and experimental research, which all points to the same direction (meat is less than ideal as a food choice)"

The objective data points to no such thing. When you're biased and only focus on the data which supports your viewpoint, you can easily conclude that there is "overwhelming" evidence when there isn't. But when you're truly objective, the data becomes muddy indeed.

Don's posts over the last 2 years show this clearly. You can go back and read all his prior pro-meat post where he lays out evidence in favor of meat. Now he posts about the evidence against meat. In neither case is the evidence particularly compelling, at least not enough to form the the kinds of supposedly rock-solid conclusions that Don (and perhaps you too by the sounds of it) likes to draw.

"And, out of curiosity, why do you defend meat so much? Why would it matter if meat is not good for health? Seriously?"

Everyone who points out the shoddiness of studies like this one must be hardened, blind meat devotees, right?

I'm not defending meat per se. I'm just finding amusement in all the conclusions people draw from shoddy data. It works both ways -- the "Meat is awesome!!" folks tend to do the same thing. For anyone to call the evidence "overwhelming" is simply ridiculous. It immediately shows that nothing they have to say on the matter can be taken seriously.

Don said...


The fact that in my paleo haze I attempted to defend meat-eating mostly by attacking evidence against it doesn't count as evidence that meat eating is without hazard. I don't recall producing much if any evidence that eating meat increases lifespan or protects against heart disease or cancer.

Simply, I was wrong and I am in this post showing you a bit of the evidence that I was wrong and why I changed my mind, based on evidence.

I challenge you to show us that science has produced just as much evidence in favor of meat-eating as against. Show me a list of studies suggesting that meat-eating reduces risks of chronic diseases and reduces mortality risk, that is at least as large as the list of studies discuss here in my post, and in comments.

"If you step back and look at the data (on beef and cancer), the optimum amount of red meat you eat should be zero."
- Walter Willett, M.D., Chairman of the Nutrition Department, Harvard

He apparently doesn't think the data is shoddy, and he apparently does think it overwhelmingly points to his conclusion. You apparently think that we should not take anything Willet has to say on the matter seriously, despite the fact that he is an eminent scientist who has conducted some of the most important and peer-reviewed research on nutrition and health. You must think that no one should take Walter Willet, M.D., Ph.D., seriously when he says that the optimal amount of red meat in a modern diet is zero.

You have done nothing to show that any data is shoddy, yet you persist in calling it so.

Frank said...


I'm not biased, I said myself that i'm a meat eater and that i'm not gonna give up meat entirly, yet I can be objective enough to admit that meat effect on health are far from impressive.

I'm gonna repeat what Don just said here but I would also like to see how many studies find benefits to meat consumption - none, as far as i'm aware - versus the huge quantity of studies which found that plants product reduce disease risk.

You seem to be a science denialist. So you believe that all the science out there - pro or anti meat - is useless and shoddy?

What do you base you dietary choices on, then?

nothing91 said...


"The fact that in my paleo haze I attempted to defend meat-eating mostly by attacking evidence against it doesn't count as evidence that meat eating is without hazard."

You did a lot more than that. I guess you already forgot. Quotes provided at the end of my post to refresh your memory.

"Show me a list of studies suggesting that meat-eating reduces risks of chronic diseases and reduces mortality risk, that is at least as large as the list of studies discuss here in my post, and in comments."

Who said anything about meat reducing the risk of anything? Certainly not me. The issue at hand is whether it increases certain risks. And based on my comments thus far about (nutritional) epidemiology, it should be pretty obvious that I don't have a bunch of such "studies" bookmarked to list out for you. They're nonsense. Pseudoscience perpetuated by researchers who actually think they're capable of controlling for an essentially infinite number of variables.

"You have done nothing to show that any data is shoddy, yet you persist in calling it so."

I already explained why this study's conclusions are worthless. You just chose not to hear.

Anyway, I'm heading out of town for a few days, so I'm afraid I won't be able to continue to liven up the comments section. :-)


To clarify a point, when I say that humans are specifically adapted to a primarily carnivorous diet, I mean this...

This new research suggests that the creatine provided by meat also supports better cognitive function among carnivores compared to vegetarians.

These types of findings indicate that humans have long ago adapted to and become dependent upon meat.

Humans need meat for optimum health of the nervous system, and the anthropological and experimental evidence already indicates eating meat can literally make you "smarter" than if you don't eat meat.

Diets High in Fish (and Meat) Linked to Stronger Bones

Oops, the "meat is bad" hypothesis proven wrong again. Looks like eating foods rich in AA can build your bones and prevent inflammation and oxidative stress in your colon.

To build strong bodies 12 ways, eat meat, including fish. Meat is Medicine. Again.

We have evidence that a meat-based, low-carb diet may prevent or reverse Alzheimer's.

Thus, a low-sugar, high-fat, meat-based diet may serve as both preventive and remedial medicine for Alzheimer's disease.

Know someone with PCOS? Share this with them: Sugar is poison, meat is medicine.

Jimmy Gee said...


Quote from Gary Taubes:

"Back in 2007 when I first published Good Calories, Bad Calories I also wrote a cover story in the New York Times Magazine on the problems with observational epidemiology. The article was called “Do We Really Know What Makes Us Healthy?” and I made the argument that even the better epidemiologists in the world consider this stuff closer to a pseudoscience than a real science. I used as a case study the researchers from the Harvard School of Public Health, led by Walter Willett, who runs the Nurses’ Health Study. In doing so, I wanted to point out one of the main reasons why nutritionists and public health authorities have gone off the rails in their advice about what constitutes a healthy diet. The article itself pointed out that every time in the past that these researchers had claimed that an association observed in their observational trials was a causal relationship, and that causal relationship had then been tested in experiment, the experiment had failed to confirm the causal interpretation — i.e., the folks from Harvard got it wrong. Not most times, but every time. No exception. Their batting average circa 2007, at least, was .000."

The problem with epidemiology is that many confer cause and effect when finding an association. Reporting findings in this context is irresponsible and harmful. Much of what you cite as "evidence" is simply regurgitation of more associations.

Who knows, maybe someday, the nutrition researchers will actually prove something - I doubt that it will happen soon given the complexity of the human body in conjunction with its interaction with the environment.

Frank said...

Jimmy Gee

Not adressed to me but...

There will never be a nutrition study that can conclude 100% sure about something, mainly because nutrition-health related effect just take too damn long to manifest.

So we are stock with long term epidemiology, short-term experimental study and mechanistical/animal study.

We have enough indirect evidence to have a pretty good idea of the effect of meat on health... and the data are pretty consistent.

When only 5 study find a link based on observation, it probably warrants skepticism, but when thousand of papers come to the same conclusion...

We're all aware that there are confounding factors in such studies. BUT, are we to assume that all meat eater have unhealthy lifestyle? And are we to assume that all vegetarians have healthy lifestyle?

There is a consistant pattern in the litterature regarding both meat and health (bad) and plant and health (good) this, as far back as 50+ years.

The danger of smoking are based on epidemiology - would you contradidct that smoking if bad for the health base on this?

Jimmy Gee said...


I'm not contradicting - just not ready to accept observational data that produces very low risk ratios as definitive.

I would accept smoking as bad for a couple of reasons - relative risk for smoking determined through observational study has always been reported as very high - risk ration ~20, and I've seen the lungs of cadavers who smoked their whole life.

As for consistent patterns - don't care (doubt there are thousands of them, but if you say so?) - very low risk ratios are too dubious to take seriously in light of potential confounding.

Frank said...

Jimmy Gee

I'd rather side on the at best beneficial or at worst neutral (plant food), then the at best neutral at worst detrimental (meat).

What data is there that a (sound) vegeterian diet is unhealthy? So it at least won't do much harm, in comparison to the vast litterature pointing meat consumption with health hazard, even if the science is not ultra clear.

Again, i'd rather be precautios and go with the better odds.

Especially considering that we have a long history of plant based nutrition and not animal product based nutrition, it would only make sense that these data are what they are.

Rex said...

Unless I'm mistaken, everyone (including the researchers it seems) is overlooking the fact that animal meat consumed by almost everyone in the US is limited to muscle fiber ie hamburgers, rib eye, sirloin, filet mignon, and so on. All primitive HG groups favored the organ meat over muscle meat, because the former was loaded with beneficial nutrients. In addition, traditional Chinese medicine recommends the consumption of organ meats to tonify certain systems. I would like to see all of these experiments repeated with offal: kidney, liver, intestine, sweetbreads, brain, marrow, etc. I would be very surprised if the results were identical…

Rex said...

Disregard my earlier comment. I now believe offal is best consumed in 2-3 oz quantities, if at all, and only with plenty of other vegetables in a soup and in cases where rapid nutrient intake is essential for survival. For the moment, I believe meat is likely to shorten one's lifespan.

Rex said...

Disregard my earlier comment. I now believe offal is best consumed in 2-3 oz quantities, if at all, and only with plenty of other vegetables in a soup and in cases where rapid nutrient intake is essential for survival. For the moment, I believe meat is likely to shorten one's lifespan.

Eva said...

OK, I kept thinking about it and other things are bothering me like this one, "Does the panda challenge the idea that "the natural diet of mammals is a high-fat diet"? Who has that idea? You can't lump all mammals together. Each mammal has different foods that are best for it. Also, although high fat is popular in some subgroups of paleo eaters, it's not the standard for paleo. Many advocate moderate amounts of fat and some advocate low fat. The main standard is the fat be from a healthy source.

Another strange statement, "Any species that at any time in its evolution adopts a meat-based diet is required thenceforth to always maintain a meat-based diet to sustain health. " No one ever said any such thing, except apparently you. If you truly want to argue fairly against a different opinion, you should first make the effort to understand correctly the opinion you are arguing against and portray it fairly.