In understanding human health, we have to look at all factors as a package deal. Our gut-brain is a system, as is our entire mind-body. Our relationships, lifestyle, the environment around us — all of it is inseparable. This is true even if we limit ourselves to diet alone. It’s not simply calories in/calories out, macronutrient ratios, or anything else along these lines. It is the specific foods eaten in combination with which other foods and in the context of stress, toxins, epigenetic inheritance, gut health, and so much else that determine what effects manifest in the individual.
There are numerous examples of this. But I’ll stick to a simple one, which involves several factors and the relationship between them. First, red meat is associated with cancer and heart disease. Yet causation is hard to prove, as red meat consumption is associated with many other foods in the standard American diet, such as added sugars and vegetable oils in processed foods. The association might be based on confounding factors that are culture-specific, which can explain why we find societies with heavy meat consumption and little cancer.
So, what else might be involved? We have to consider what red meat is being eaten with, at least in the standard American diet that is used as a control in most research. There is, of course, the added sugars and vegetable oils — they are seriously bad for health and may explain much of the confusion. Saturated fat intake has been dropping since the early 1900s and, in its place, there has been a steady rise in the use of vegetable oils; we now know that highly heated and hydrogenated vegetable oils do severe damage. Also, some of the original research that blamed saturated fat, when re-analyzed, found that sugar was the stronger correlation to heart disease.
Saturated fat, as with cholesterol, had been wrongly accused. This misunderstanding has, over multiple generations at this point, led to the early death of at least hundreds of millions of people worldwide, as dozens of the wealthiest and most powerful countries enforced this in their official dietary recommendations which transformed the world’s food system. Similar to eggs, red meat became the fall guy.
Such things as heart disease are related to obesity, and conventional wisdom tells us that fat makes us fat. Is that true? Not exactly or directly. I was amused to discover that a scientific report commissioned by the British government in 1846 (Experimental Researches on the Food of Animals, and the Fattening of Cattle: With Remarks on the Food of Man. Based Upon Experiments Undertaken by Order of the British Government by Robert Dundas Thomson) concluded that “The present experiments seem to demonstrate that the fat of animals cannot be produced from the oil of the food” — fat doesn’t make people fat, and that low-carb meat-eating populations tend to be slim has been observed for centuries.
So, in most cases, what does cause fat accumulation? It is only fat combined with plenty of carbs and sugar that is guaranteed to make us fat, that is to say fat in the presence of glucose in that the two compete as a fuel source.
Think about what an American meal with red meat looks like. A plate might have a steak with some rolls or slices of bread, combined with a potato and maybe some starchy ‘vegetables’ like corn, peas, or lima beans. Or there will be a hamburger with a bun, a side of fries, and a large sugary drink (‘diet’ drinks are no better, as we now know artificial sweeteners fool the body and so are just as likely to make you fat and diabetic). What is the common factor, red meat combined with wheat or some other grain, as part of a diet drenched in carbs and sugar (and all of it cooked or slathered in vegetable oils).
Most Americans have a far greater total intake of carbs, sugar, and vegetable oils than red meat and saturated fat. The preferred meat of Americans these days is chicken with fish also being popular. Why does red meat and saturated fat continue to be blamed for the worsening rates of heart disease and metabolic disease? It’s simply not rational, based on the established facts in the field of diet and nutrition. That isn’t to claim that too much red meat couldn’t be problematic. It depends on the total diet. Also, Americans have the habit of grilling their red meat and grilling increases carcinogens, which could be avoided by not charring one’s meat, but that equally applies to not burning (or frying) anything one eats, including white meat and plant foods. In terms of this one factor, you’d be better off eating beef roasted with vegetables than to go with a plant-based meal that included foods like french fries, fried okra, grilled vegetable shish kabobs, etc.
Considering all of that, what exactly is the cause of cancer that keeps showing up in epidemiological studies? Sarah Ballantyne has some good answers to that (see quoted passage below). It’s not so much about red meat itself as it is about what red meat is eaten with. The crux of the matter is that Americans eat more starchy carbs, mostly refined flour, than they do vegetables. What Ballantyne explains is that two of the potential causes of cancer associated with red meat only occur in a diet deficient in vegetables and abundant in grains. It is the total diet as seen in the American population that is the cause of high rates of cancer.
As a heavy meat diet without grains is not problematic, a heavy carb diet without grains is also not necessarily problematic. Some of the healthiest populations eat lots of carbs like sweet potatoes, but you won’t find any healthy population that eats as many grains as do Americans. There are many issues with grains considered in isolation (read the work of David Perlmutter or any number of writers on the paleo diet), but grains combined with certain other foods in particular can contribute to health concerns.
Then again, some of this is about proportion. For most of the time of agriculture, humans ate small amounts of grains as an occasional food. Grains tended to be stored for hard times or for trade or else turned into alcohol to be mixed with water from unclean sources. The shift to large amounts of grains made into refined flour is an evolutionarily unique dilemma our bodies aren’t designed to handle. The first accounts of white bread are found in texts from slightly over two millennia ago and most Westerners couldn’t afford white bread until the past few centuries when industrialized milling began. Before that, people tended to eat foods that were available and didn’t mix them as much (e.g., eat fruits and vegetables in season). Hamburgers were invented only about a century ago. The constant combining of red meat and grains is not something we are adapted for. That harm to our health results maybe shouldn’t surprise us.
Red meat can be a net loss to health or a net gain. It depends not on the red meat, but what is and isn’t eaten with it. Other factors matter as well. Health can’t be limited to a list of dos and don’ts, even if such lists have their place in the context of more detailed knowledge and understanding. The simplest solution is to eat as most humans ate for hundreds of thousands of years, and more than anything else that means avoiding grains. Even without red meat, many people have difficulties with grains.
Let’s return to the context of evolution. Hominids have been eating fatty red meat for millions of years (early humans having prized red meat from blubbery megafauna until their mass extinction), and yet meat-eating hunter-gatherers rarely get cancer, heart disease, or any of the other modern ailments. How long ago was it when the first humans ate grains? About 12 thousand years ago. Most humans on the planet never touched a grain until the past few millennia. And fewer still included grains with almost every snack and meal until the past few generations. So, what is this insanity of government dietary recommendations putting grains as the base of the food pyramid? Those grains are feeding the cancerous microbes, and doing much else that is harmful.
In conclusion, is red meat bad for human health? It depends. Red meat that is charred or heavily processed combined with wheat and other carbs, lots of sugar and vegetable oils, and few nutritious vegetables, well, that would be a shitty diet that will inevitably lead to horrible health consequences. Then again, the exact same diet minus the red meat would still be a recipe for disease and early death. Yet under other conditions, red meat can be part of a healthy diet. Even a ton of pasture-raised red meat (with plenty of nutrient-dense organ meats) combined with an equal amount of organic vegetables (grown on healthy soil, bought locally, and eaten in season), in exclusion of grains especially refined flour and with limited intake of all the other crap, that would be one of the healthiest diets you could eat.
On the other hand, if you are addicted to grains as many are and can’t imagine a world without them, you would be wise to avoid red meat entirely. Assuming you have any concerns about cancer, you should choose one or the other but not both. I would note, though, that there are many other reasons to avoid grains while there are no other known reasons to avoid red meat, at least for serious health concerns, although some people exclude red meat for other reasons such as digestion issues. The point is that whether or not you eat red meat is a personal choice (based on taste, ethics, etc), not so much a health choice, as long as we separate out grains. That is all we can say for certain based on present scientific knowledge.
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We’ve known about this for years now. Isn’t it interesting that no major health organization, scientific institution, corporate news outlet, or government agency has ever warned the public about the risk factors of carcinogenic grains? Instead, we get major propaganda campaigns to eat more grains because that is where the profit is for big ag, big food, and big oil (that makes farm chemicals and transports the products of big ag and big food). How convenient! It’s nice to know that corporate profit is more important than public health.
But keep listening to those who tell you that cows are destroying the world, even though there are fewer cows in North America than there once were buffalo. Yeah, monocultural GMO crops immersed in deadly chemicals that destroy soil and deplete nutrients are going to save us, not traditional grazing land that existed for hundreds of millions of years. So, sure, we could go on producing massive yields of grains in a utopian fantasy beloved by technocrats and plutocrats that further disconnects us from the natural world and our evolutionary origins, an industrial food system dependent on turning the whole world into endless monocrops denatured of all other life, making entire regions into ecological deserts that push us further into mass extinction. Or we could return to traditional ways of farming and living with a more traditional diet largely of animal foods (meat, fish, eggs, dairy, etc) balanced with an equal amount of vegetables, the original hunter-gatherer diet.
Our personal health is important. And it is intimately tied to the health of the earth. Civilization as we know it was built on grains. That wasn’t necessarily a problem when grains were a small part of the diet and populations were small. But is it still a sustainable socioeconomic system as part of a healthy ecological system? No, it isn’t. So why do we continue to do more of the same that caused our problems in the hope that it will solve our problems? As we think about how different parts of our diet work together to create conditions of disease or health, we need to begin thinking this way about our entire world.
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by Sarah Ballantyne
While this often gets framed as an argument for going vegetarian or vegan. It’s actually a reflection of the importance of eating plenty of plant foods along with meat. When we take a closer look at these studies, we see something extraordinarily interesting: the link between meat and cancer tends to disappear once the studies adjust for vegetable intake. Even more exciting, when we examine the mechanistic links between meat and cancer, it turns out that many of the harmful (yes, legitimately harmful!) compounds of meat are counteracted by protective compounds in plant foods.
One major mechanism linking meat to cancer involves heme, the iron-containing compound that gives red meat its color (in contrast to the nonheme iron found in plant foods). Where heme becomes a problem is in the gut: the cells lining the digestive tract (enterocytes) metabolize it into cytotoxic compounds (meaning toxic to living cells), which can then damage the gut barrier (specifically the colonic mucosa; see page 67), cause cell proliferation, and increase fecal water toxicity—all of which raise cancer risk. Yikes! In fact, part of the reason red meat is linked with cancer far more often than with white meat could be due to their differences in heme content; white meat (poultry and fish) contains much, much less.
Here’s where vegetables come to the rescue! Chlorophyll, the pigment in plants that makes them green, has a molecular structure that’s very similar to heme. As a result, chlorophyll can block the metabolism of heme in the intestinal tract and prevent those toxic metabolites from forming. Instead of turning into harmful by-products, heme ends up being metabolized into inert compounds that are no longer toxic or damaging to the colon. Animal studies have demonstrated this effect in action: one study on rats showed that supplementing a heme-rich diet with chlorophyll (in the form of spinach) completely suppressed the pro-cancer effects of heme. All the more reason to eat a salad with your steak.
Another mechanism involves L-carnitine, an amino acid that’s particularly abundant in red meat (another candidate for why red meat seems to disproportionately increase cancer risk compared to other meats). When we consume L-carnitine, our intestinal bacteria metabolize it into a compound called trimethylamine (TMA). From there, the TMA enters the bloodstream and gets oxydized by the liver into yet another compound, trimethylamine-N-oxide (TMAO). This is the one we need to pay attention to!
TMAO has been strongly linked to cancer and heart disease, possibly due to promoting inflammation and altering cholesterol transport. Having high levels of it in the bloodstream could be a major risk factor for some chronic diseases. So is this the nail in the coffin for meat eaters?
Not so fast! An important study on this topic published in 2013 in Nature Medicine sheds light on what’s really going on. This paper had quite a few components, but one of the most interesting has to do with gut bacteria. Basically, it turns out that the bacteria group Prevotella is a key mediator between L-carnitine consumption and having high TMAO levels in our blood. In this study, the researchers found that participants with gut microbiomes dominated by Prevotella produced the most TMA (and therefore TMAO, after it reached the liver) from the L-carnitine they ate. Those with microbiomes high in Bacteroides rather than Prevotella saw dramatically less conversion to TMA and TMAO.
Guess what Prevotella loves to snack on? Grains! It just so happens that people with high Prevotella levels, tend to be those who eat grain-based diets (especially whole grain), since this bacterial group specializes in fermenting the type of polysaccharides abundant in grain products. (For instance, we see extremely high levels of Prevotella in populations in rural Africa that rely on cereals like millet and sorghum.) At the same time, Prevotella doesn’t seem to be associated with a high intake of non-grain plant sources, such as fruit and vegetables.
So is it really the red meat that’s a problem . . . or is it the meat in the context of a grain-rich diet? Based on the evidence we have so far, it seems that grains (and the bacteria that love to eat them) are a mandatory part of the L-carnitine-to-TMAO pathway. Ditch the grains, embrace veggies, and our gut will become a more hospitable place for red meat!
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Georgia Ede has a detailed article about the claim of meat causing cancer. In it, she provides several useful summaries of and quotes from the scientific literature.
In November 2013, 23 cancer experts from eight countries gathered in Norway to examine the science related to colon cancer and red/processed meat. They concluded:
“…the interactions between meat, gut and health outcomes such as CRC [colorectal cancer] are very complex and are not clearly pointing in one direction….Epidemiological and mechanistic data on associations between red and processed meat intake and CRC are inconsistent and underlying mechanisms are unclear…Better biomarkers of meat intake and of cancer occurrence and updated food composition databases are required for future studies.” 1) To read the full report: http://www.ncbi.nlm.nih.gov/pubmed/24769880 [open access]
Translation: we don’t know if meat causes colorectal cancer. Now THAT is a responsible, honest, scientific conclusion.
How the WHO?
How could the WHO have come to such a different conclusion than this recent international gathering of cancer scientists? As you will see for yourself in my analysis below, the WHO made the following irresponsible decisions:
- The WHO cherry-picked studies that supported its anti-meat conclusions, ignoring those that showed either no connection between meat and cancer or even a protective effect of meat on colon cancer risk. These neutral and protective studies were specifically mentioned within the studies cited by the WHO (which makes one wonder whether the WHO committee members actually read the studies referenced in its own report).
- The WHO relied heavily on dozens of “epidemiological” studies (which by their very nature are incapable of demonstrating a cause and effect relationship between meat and cancer) to support its claim that meat causes cancer.
- The WHO cited a mere SIX experimental studies suggesting a possible link between meat and colorectal cancer, four of which were conducted by the same research group.
- THREE of the six experimental studies were conducted solely on RATS. Rats are not humans and may not be physiologically adapted to high-meat diets. All rats were injected with powerful carcinogenic chemicals prior to being fed meat. Yes, you read that correctly.
- Only THREE of the six experimental studies were human studies. All were conducted with a very small number of subjects and were seriously flawed in more than one important way. Examples of flaws include using unreliable or outdated biomarkers and/or failing to include proper controls.
- Some of the theories put forth by the WHO about how red/processed meat might cause cancer are controversial or have already been disproved. These theories were discredited within the texts of the very same studies cited to support the WHO’s anti-meat conclusions, again suggesting that the WHO committee members either didn’t read these studies or deliberately omitted information that didn’t support the WHO’s anti-meat position.
Does it matter whether the WHO gets it right or wrong about meat and cancer? YES.
“Strong media coverage and ambiguous research results could stimulate consumers to adapt a ‘safety first’ strategy that could result in abolishment of red meat from the diet completely. However, there are reasons to keep red meat in the diet. Red meat (beef in particular) is a nutrient dense food and typically has a better ratio of N6:N3-polyunsaturated fatty acids and significantly more vitamin A, B6 and B12, zinc and iron than white meat(compared values from the Dutch Food Composition Database 2013, raw meat). Iron deficiencies are still common in parts of the populations in both developing and industrialized countries, particularly pre-school children and women of childbearing age (WHO)… Red meat also contains high levels of carnitine, coenzyme Q10, and creatine, which are bioactive compounds that may have positive effects on health.” 2)
The bottom line is that there is no good evidence that unprocessed red meat increases our risk for cancer. Fresh red meat is a highly nutritious food which has formed the foundation of human diets for nearly two million years. Red meat is a concentrated source of easily digestible, highly bioavailable protein, essential vitamins and minerals. These nutrients are more difficult to obtain from plant sources.
It makes no sense to blame an ancient, natural, whole food for the skyrocketing rates of cancer in modern times. I’m not interested in defending the reputation of processed meat (or processed foods of any kind, for that matter), but even the science behind processed meat and cancer is unconvincing, as I think you’ll agree. […]
Regardless, even if you believe in the (non-existent) power of epidemiological studies to provide meaningful information about nutrition, more than half of the 29 epidemiological studies did NOT support the WHO’s stance on unprocessed red meat and colorectal cancer.
It is irresponsible and misleading to include this random collection of positive and negative epidemiological studies as evidence against meat.
The following quote is taken from one of the experimental studies cited by the WHO. The authors of the study begin their paper with this striking statement:
“In puzzling contrast with epidemiological studies, experimental studies do not support the hypothesis that red meat increases colorectal cancer risk. Among the 12 rodent studies reported in the literature, none demonstrated a specific promotional effect of red meat.” 3)
[Oddly enough, none of these twelve “red meat is fine” studies, which the authors went on to list and describe within the text of the introduction to this article, were included in the WHO report].
I cannot emphasize enough how common it is to see statements like this in scientific papers about red meat. Over and over again, researchers see that epidemiology suggests a theoretical connection between some food and some health problem, so they conduct experiments to test the theory and find no connection. This is why our nutrition headlines are constantly changing. One day eggs are bad for you, the next day they’re fine. Epidemiologists are forever sending well-intentioned scientists on time-consuming, expensive wild goose chases, trying to prove that meat is dangerous, when all other sources–from anthropology to physiology to biochemistry to common sense—tell us that meat is nutritious and safe.