Dr. David Klurfeld on Meat NOT Causing Cancer, Bogus Vegetarian Scientists, and Balanced Nutrition.
This is an interview by Brian Sanders on Peak Human. I thought it was so important I transcribed a good bit of it.
Introduction
Somehow I missed this video and podcast when they came out. I just happened upon them recently, serendipitously (Sanders, 2019, 2020).
Brian lists Dr. Klurfeld's credentials as:
"David Klurfeld is the National Program Leader for Human Nutrition in the Agricultural Research Service of the USDA. He was Editor-in-Chief of the Journal of the American College of Nutrition for 6 years and is currently Associate Editor of the American Journal for Clinical Nutrition."
So not exactly a lightweight in the field.
“Dr. David Klurfeld on Meat NOT Causing Cancer, Bogus Vegetarian Scientists, and Balanced Nutrition.”
This is not a complete transcript, it’s just the parts that are of interest to me, mainly his commentary on his experience with vegetarian scientists.
All quotes below are from Dr. Klurfeld, unless indicated otherwise. All citations are my own, so may not be accurate to what Dr. Klurfeld meant, and any errors in transcription are my own.
Basic Problems with Nutrition Science.
“Unfortunately, I have a number of colleagues in the nutrition research field, who are claiming that diet accounts for 70% of all of the cardiovascular deaths in the United States. And as you said, there’s no real way of knowing. So in fact, there was a paper in the Journal of the American Medical Association last year (Micha et al., 2017), claiming 70% of all deaths to ten specific dietary factors, and although the editors accepted that for publication, they commissioned an editorial (Mueller & Appel, 2017) in the same issue of that journal written by a couple of nutrition experts, who disputed the ten factors, the amount of deaths that were calculated. In fact they said, ‘The finding appear correct, but instead of 70%, the reduction could be 30%;’ and if the reduction could be 30%, well, maybe it could be 10%. And this is the real problem: that we don’t have solid, quantitative data, yet there are people on soap boxes constantly saying ‘But I have the answer’, telling you what to do.
“High salt is number one. Low nuts and seeds is number two. And I’ve never met a person I could diagnose with a nut and seed deficiency. High processed meats is third on the list, and it’s not just how much you are eating of processed meats, but it’s any amount of processed meats, according to this analysis, is responsible for more than 10% of the deaths in men, and almost 6% of the deaths in women in the United States. So just mull that over for a little bit, it’s just not plausible….
“I just think this is an opinion, I don’t think this is good research.
“High unprocessed red meat was the smallest factor, accounting for a fraction of a percent of the deaths.
“They want high polyunsaturated fats… Well that’s another very controversial topic. I’m actually a fan of some amount of PUFA in the diet, but I can’t give you an evidence-based estimate of what I think is the proper range….
“The government actually has established acceptable ranges of these things, yet there are paper after paper in the literature saying this is the cut-off of how much you are allowed to eat. And I don’t think the evidence really supports that point of view, at all.”
Long discussion of (Ioannidis, 2018), much of it mocking nutritional epidemiology. “If you do all these things, you’ll truly never die. Except from laughing too hard at these representations.”
Klurfeld quotes, “These implausible estimates of benefits or risks associated with diet probably reflect almost exclusively the magnitude of the cumulative biases in this type of research, with extensive residual confounding and selective reporting. (Ioannidis, 2018)”
“So in fact, meat consumption has been associated with heart disease, stroke, kidney disease, diabetes, obesity, half a dozen different kinds of cancer, and total mortality. And if you said there was one drug, or one chemical, that caused all those diseases, no one would believe you.”
Yep, it would sound crazy. Indeed.
“But everyone is lining up and saying, “Oh yeah, red meat is killing us”, from all of these different directions. It’s really not plausible, if you think about it objectively…. “We’ve been eating meat since before we became humans. Meat contributed, it’s thought, by anthropologists, to our becoming humans from these little subhumans who had smaller brains, but when they found the ability to hunt other critters, and eat the meat, that provided the nutrients that allowed us to evolve into human beings.
“I believe you can be a healthy vegetarian, but you really need to be a well-educated vegetarian. And most people who follow various type of restrictive diet, whatever they are cutting out, find it more difficult to get what they need. And that’s been reinforced in multiple studies of peoples diets in the United States and in Europe….” Discusses various problems with getting enough complete protein and micronutrients from plant foods. “Selenium, you get more than half you requirement of selenium in three ounces of meat. You can eat Brazil nuts to get selenium, but most Americans aren’t chowing down on Brazil nuts on a regular basis….
“You have to think less about your diet if you are eating a wide variety of foods, and that’s why I’d like to see an omnivorous diet recommended for the best health.”
Long discussion about fiber, that I will skip.
Diet and Chronic, Non-Communicable Disease Risk
“Nothing would get an A grade in nutrition, except for preventing deficiency diseases… The cancer grades would be a C or a D. Despite the fact that we’ve had decades of research in these areas, thousands of studies, gazillions of dollars spent on it, there’s nothing that I can say to your listeners, that will definitely prevent or cause any type of cancer from the diet alone…
“We know actually, from the diet that eating moldy peanuts or moldy corn will increase your risk of some cancers of the stomach and liver. It’s well established that there’s a fungus that grows on these plants that is prevalent in Africa and Asia, and it increases your risk of liver and stomach cancer six-fold [a 500% increase]. The types of risk that we’re talking about for processed meat and colon cancer is less than 1.2 [a 20% increase] and six-fold is five times 1.2.
“Cigarette smoke and lung cancer is 10 to 30-fold increased risk. Those are real risks, that you can be confident in. With these risks of 1.1, 1.2, you can’t be confident if that’s a real risk, or if that’s noise in the system. And you certainly can’t ascribe it so a single factor when five or 10 health behaviors all correlate very strongly.
“The problem is that most of the science that gets the attention in the news media, are these observational studies, that are totally uncontrolled. So you ask somebody, “What have you eaten for the last year?”, and you fill out a questionnaire, that has 150 questions on it. But, think of this, if it’s summertime and your eating watermelon and peaches and strawberries, doesn’t that color what you think you ate last February, when those things weren’t in season? This is a real problem in evaluating what people have eaten.
“In nutrition we say those correlations are cause and effect, when we know they’re not.”
Biased Vegetarians In Science
On his appearance in Forks Over Knives (Fulkerson, 2013):
“He explained to me that they wanted to have a balanced presentation in there. And they sent five people from the West Coast to Maryland to interview me. And they filmed me for over an hour. And I was on screen for 45 seconds, maybe. So most of my interview was on the cutting-room floor. And they exactly, what you said, they took out all the parts that I wanted in my message and made it appear that the Department of Agriculture was promoting meat-based diets and who funded your research was more important than what your findings were. And I certainly believe that you need to pay attention to who funds research. But, I can tell you with 100% certainty, that the food industry does not influence the research that we do in the Dept. of Agriculture….
“So, related to this film, it became clear that the stars of the film were activist vegetarian scientists and physicians, who had an agenda to make anybody who said that eating meat is OK, not just good for you, but OK, were the devil incarnate. And I think there’s a personal agenda there. I’ve seen that with committees that I’ve been on, and other committees that have put out recommendations, that vegetarians don’t seem satisfied on those committees unless you agree to be a vegetarian. And the meat eaters on those committees don’t seem to want to force you to start eating roast beef.
“So I actually believe that being a vegetarian is a conflict of interest on these committees that make dietary recommendations. And I have first-hand experience, three years ago, having been on the World Heath Organization working group that evaluated processed and red meat and risk of cancer (Bouvard et al., 2015; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2018). For me, that was the most frustrating professional experience of my life….
“We had these 22 scientists from 10 different countries. Half of the scientists were epidemiologists. I’m an experimentalist, and we had a small number of experimental people on the committee, and since the largest number were epidemiologists, and the animal studies did not point to a cancer risk from either red or processed meats by the ground rules of the IARC, they defaulted to using these observational studies. In the summary that was published, they said we looked at more than 800 studies. And that was true, but they only used 18 studies, to come to the conclusion, out of 800. And, for processed meat, only 12 out of 18 said that there was a risk. And for red meat, there were only 14 studies in total, and only seven of those, so it’s a 50/50 proposition that red meat increased the risk. And the risk is an association, it’s not cause-and-effect. Observational studies can never prove cause and effect. And this is, I think, where the science is fatally flawed in this decision. But there was essentially a majority vote, and that’s what it came down to… It was non unanimous, or near unanimous.”
Brian Sanders: “Yeah you wrote an article about this, that I read, in a journal, as well.” [I think it’s (Klurfeld, 2015)]
“As I prefaced this by saying it was the most frustrating professional experience of my life, in fact, in some ways I believe that many of the scientists who came to this working group had their minds made up before they heard any of the evidence. And I really thought when I got there—I’m no longer young, but I’m still naïve—that people would listen to the evidence and change their minds. So I actually raised a couple of issues that were ignored. So they had these 800 observational studies; and I said, well what about the two controlled feeding studies that had been published looking at breast and colon cancer?
“I need to tell your listeners a little bit about that, just briefly. So one was done by the National Cancer Institute, with 900 people in each of two different groups. These were people who had an intestinal polyp removed on a colonoscopy. If you got one polyp, you’re at greatly increased risk of getting another one. So 900 or so people were told, “Go home and follow your regular diet. The other 900 people were told go home and eat a “good diet”. So the good diet was low in red and processed meats, low in fat, high in fruits and vegetables, and high in whole grains. All of the things that we’re told that we’re supposed to be doing for good health. Three years later, they come back for their repeat colonoscopy, the relative risk of getting a second polyp was exactly the same for both diets…. [Can’t find this study, so no reference.]
“So the question remains, well maybe the polyp is not a cancer, it’s a pre-cancerous risk factor. Maybe that not the right time to intervene.
“So we had the biggest health study in history, was the Woman’s Health Initiative (Beresford et al., 2006). Most of that was actually published in 2006, but it was a $750 million study, and the biggest chunk of that was the diet study, with a low-fat diet. In 20,000 women on a low-fat diet, 30,000 women, on a control diet. So now we’re talking huge, huge numbers, for nine years. And again, no difference in risk with colon cancer following the low-fat, or the typical American higher-fat. Not even a hint of a benefit [in fact, the low-fat group did worse]. And so I said, what about these two studies? And the response from one of the epidemiologists was, “These studies were not designed to study red meat.” Which is true, but neither were any of the observational studies….
“In nutrition research, we always view specific interventions like this as much stronger evidence than these observational studies….
“For this IARC committee that I was on, they don’t rely just on observationals and uncontrolled human studies, they also would like to see controlled human studies—which don’t exist for meat, specifically—or animal studies, which they have, but does not implicate meat in any fashion. And then the last part of the evidence that they use are mechanistic studies, but mechanistic studies the way they interpret do not prove cause and effect. What they do is establish simply that there is a plausible relationship. And it turns out, that one of the people on the committee, who has studied these mechanisms has published two papers feeding bacon to rats (Parnaud et al., 1998, 2000) and given a chemical that induces colon cancer in these animals, and eating a diet high in bacon actually reduces the precancerous lesions.
“They ignored that. This was published in two separate experiments. So what they focused on was other experiments that group had published where they fed rats a specific food as a source of protein that I don’t consider meat. It was blood sausage. They were feeding that as the only protein source, at three times the usual level of protein intake that a rat needs, combined with a calcium-deficient diet. So if you’re eating three times the meat you need…”
Brian Sanders: “Or blood sausage.”
“…and you have a calcium deficient diet, maybe you have the right mechanism in your body that could increase your risk of cancer.
“So it’s an incredibly specific set of circumstances that they relied on, and said this proves that the observational studies are real. And I just don’t think that that’s good science….”
Brian Sanders: “…So, there’s a clear bias here. Were there public vegetarians in this?”
“Yes. Actually there were quite a few vegetarians on the committee, in fact the first night we were there we had a group dinner at a restaurant, and I was sitting next to one of the staff members from WHO, and I expressed the view that I felt the members of the working group should declare that those who are vegetarians, because I feel that is a conflict of interest. And she laughed and said, “Well I’m a vegetarian.” So we changed the topic of discussion.
But I really do think that intellectual biases are stronger and undeclared in research. So if a scientist is supported by the beef industry, financially, on a particular study, almost every journal now requires you have a printed disclosure on the paper. And anything you’ve done usually that’s been supported financially by any group for the last three or five years needs to be revealed, so you can make your own judgement about are these dollars influencing this person’s research. But if a person is a Seventh-day Adventist, for example, and I’ve worked with Seventh-day Adventists, and if you’re a good Seventh-day Adventist, you’re a vegetarian. So you have not only the scientific vegetarian approach but you have a religious reason to be a vegetarian. Do you need to declare that? I don’t see any declarations like that in science. I see scientists who have books for the public, refusing to declare that they have a book published for the public on following low-carbohydrate diets, as an example. I think that’s a bias, it should be declared. It might be a financial bias, but I think the academic bias that these people have is much stronger than whatever they make from the book. And I don’t know if they’re making $5 or $5 million, and frankly I don’t care what they’re making. I think the academic bias is more important to disclose in research publications than the financial rewards that they’re getting. I think both need to be disclosed….”
Brian Sanders: “Yeah, I think so. And I think these religious or moral or deep-seated beliefs like vegetarianism seem to be way more important than just the funding. I believe they affect your decision making more—your deeper-held bias.”
“Oh, I’m convinced of that. I don’t know if there are more vegetarians in the nutrition field than in the general population, but they seem to be out more. I have a lot of colleagues who tell me, “I’m a vegetarian,” or “I’ve become a vegetarian.” Everyone has there own operational definition of what a vegetarian is so some will eat fish and they think they’re a vegetarian. Some will just avoid red meat and describe themselves as vegetarians, which doesn’t fit anybody’s description of vegetarians.
“I think these are real problems and I’m not going to tell you exactly what number of people on this IARC committee were vegetarians, but my informal assessment is at least a quarter to a third of the committee were vegetarians.”
4-5% of American are vegetarians—including vegans (Hrynowski, 2019; Stahler, 2019). So vegetarians/vegans are 5-8.25 times as common in that committee as in the US population.
“So coming back to the science there, all of the studies that were reviewed by the IARC committee were the uncontrolled, observational studies that really can’t prove cause and effect, and you can really only conclude that these studies are suggestive. Not even that it’s likely. The take-home message is that there are signs that this might be true, and we need to follow them up. In other fields, that’s the approach we take, all the time. Even with the early observational studies with smoking, until it was proven in animals, and the mechanism was established, scientists did not accept that cigarettes caused cancer.
“You can make the argument that the tobacco industry hid data, that’s all true, but it’s all irrelevant, because scientists were doing government-sponsored research on that area for 24 years before the surgeon general said smoking causes cancer, and that’s how long it took. We’ve been doing government-sponsored work on diet and cancer for 40 years, and the surgeon general is not going to say that diet causes cancer, because we don’t have smoking-gun evidence. And I don’t’ think you need 100% certainty in this area. You know, if we were 80% certain, which is well below the threshold we need to claim statistical significance in scientific research, I would be inclined to go along with that advice can’t hurt you. But I don’t think we’re even at a 50/50 position here. Just flip the coin on however you want to go, and that what we can follow.”
Poor Quality Nutrition Science
Brian Sanders: “Yeah, I agree, and so nutrition science isn’t held up to the same standards…”
“You’re absolutely right.”
Brian Sanders: “Why do we accept [that]?... Why is that [these correlations] now accepted as facts?”
“Well I think part of it is, what you’ve been saying in a few different words that there’s this belief by researchers that they have the correct answer to whatever problem it is, they think that they’re saving the world from themselves by telling them, ‘Follow this diet.’
“I’ll give you one example, where we’re making the recommendation to eat more whole grains in place of refined grains. And I believe that’s probably true. But, in the last year there was a study done in Israel, feeding 200 people whole grains and 200 other people refined grains, looking at their blood sugar response. The idea is that whole grains are supposed to give you lower blood sugar which is supposed to be healthier for you. It turns out half the people in each group had higher blood sugar after whole grains compared to refined grains, and half the people had high blood sugar levels after eating refined grains.And there was no way of predicting up front who was going to get this blood glucose response to eating whole grains or refined grains. They actually analyzed the bacteria in their intestines and found people who had certain bacterial species living in their intestines were more likely to have this differential response (Korem et al., 2017)….
“…There are so many variables… With the changes in genetics making us respond differently to polyunsaturated vs. saturated fat. 20% of the population responds in the wrong way to adding polyunsaturated fat to their diet….
“By default we have these prescription, public-health, blanket recommendations, and the nutrition field has shot itself in the foot by saying we have the revealed word, and if you just listen to us, you’d live to be 186 years old. And that’s just a promise we can’t fulfill.
“I think you have to weigh your own risks, and try to evaluate research recommendations that are being made. As somebody who is pretty well educated in nutrition, and actually served as chairman of a nutrition department for a dozen years before I joined the government, I have to do my own research on every specific recommendation, and very often I throw my hands up in the air and walk away and say, ‘I’m just going to eat a little of this, and a little of that.’
“And that boils down to my own personal dietary recommendations, which are three, and I think easier to follow than, I think, any government’s recommendations.
Variety
Moderation
Enjoy what you eat. Because if you don’t, you’re not going to follow 1 or 2…”
Organic Foods and Pesticides in Regular Foods
An interesting discussion, so do listen to the whole thing.
Original post with comments here.
References
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Bouvard, V., Loomis, D., Guyton, K. Z., Grosse, Y., Ghissassi, F. E., Benbrahim-Tallaa, L., Guha, N., Mattock, H., & Straif, K. (2015). Carcinogenicity of consumption of red and processed meat. The Lancet Oncology, 16(16), 1599–1600. https://doi.org/10.1016/S1470-2045(15)00444-1
Fulkerson, L. (2013, October 16). Forks Over Knives [Documentary]. Monica Beach Media. https://www.imdb.com/title/tt1567233/
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Micha, R., Peñalvo, J. L., Cudhea, F., Imamura, F., Rehm, C. D., & Mozaffarian, D. (2017). Association Between Dietary Factors and Mortality From Heart Disease, Stroke, and Type 2 Diabetes in the United States. JAMA, 317(9), 912–924. https://doi.org/10.1001/jama.2017.0947
Mueller, N. T., & Appel, L. J. (2017). Attributing Death to Diet: Precision Counts. JAMA, 317(9), 908–909. https://doi.org/10.1001/jama.2017.0946
Parnaud, G., Peiffer, G., Taché, S., & Corpet, D. E. (1998). Effect of meat (beef, chicken, and bacon) on rat colon carcinogenesis. Nutrition and Cancer, 32(3), 165–173. https://doi.org/10.1080/01635589809514736
Parnaud, G., Pignatelli, B., Peiffer, G., Taché, S., & Corpet, D. E. (2000). Endogenous N-Nitroso Compounds, and Their Precursors, Present in Bacon, Do Not Initiate or Promote Aberrant Crypt Foci in the Colon of Rats. Nutrition and Cancer, 38(1), 74–80. https://doi.org/10.1207/S15327914NC381_11
Sanders, B. (2019, January 18). Dr. David Klurfeld on Meat NOT Causing Cancer, Bogus Vegetarian Scientists, and Balanced Nutrition (No. 24) [Mp3]. https://www.peak-human.com/post/dr-david-klurfeld-on-meat-not-causing-cancer-bogus-vegetarian-scientists-and-balanced-nutrition
Sanders, B. (2020, October 1). Meat NOT Causing Cancer, Bogus Vegetarian Scientists, and Balanced Nutrition—Dr. David Klurfeld (Vol. 24) [Mp4]. https://www.youtube.com/watch?v=JNHoF7qxSSY.
Stahler, C. (2019). How Many Adults in the U.S. are Vegetarian and Vegan | The Vegetarian Resource Group (VRG) [Propaganda]. The Vegetarian Resource Group. https://www.vrg.org/nutshell/Polls/2019_adults_veg.htm