In late October 2015, one of the nutrition establishment’s most cherished villains—red meat—hit the newsstands again in a big way. A report by the cancer agency of the revered World Health Organization (WHO) attracted major media attention by pronouncing processed meats as carcinogenic and red meat as “probably carcinogenic” to humans.1
Painting red meat with a broad brush, the WHO’s International Agency for Research on Cancer included beef, veal, pork, lamb, mutton, horse and goat in its definition, although the agency admitted that its characterization of these items as “probably carcinogenic” is based on limited evidence. The report is stronger in its condemnation of processed meats, citing evidence that is both “sufficient” and “convincing” enough to declare unambiguously as carcinogenic all meats “transformed through salting, curing, fermentation, smoking, or other processes,” including hot dogs, ham, sausages, corned beef, beef jerky, canned meats, and “meat-based preparations and sauces.”2 For lovers of bacon and prosciutto, as well as of delicious reduction sauces, this comes as bad news.
Although the WHO experts who produced the damning report reviewed studies involving over a dozen types of cancer, the report’s conclusions primarily concern colorectal cancer. Colorectal cancers are the second leading cancer killer in the United States and the third most common cancer worldwide. There are striking regional disparities in incidence, however. The highest incidence rates for colorectal cancers are in North America (the U.S. and Canada), some European countries, Australia, and New Zealand; the lowest risk is found in China, India, and parts of Africa and South America.3
THE HIDDEN ROLE OF VEGETABLE OILS
Because colorectal cancers start in the colon or rectum (which are part of the large intestine), it makes intuitive sense that diet is likely to be a determinant of increased colorectal cancer risk. Apologists for mainstream nutrition, however, have generally been unwilling to condemn any dietary factors other than the usual suspects. Thus, even before the October release of the WHO report, the standard colon cancer prevention advice featured the recommendation to limit consumption of red meat. This recommendation was buttressed by selected research identifying an apparent correlation between meat-eating and colon cancer in industrialized countries.
But there is more to the story. In their analysis of myths and truths about beef (Wise Traditions, Spring 2000),4 Sally Fallon and Mary Enig pointed to studies indicating that meat-eating is not associated with cancer in traditional societies. To understand this seeming contradiction, it is important to look closely at other elements of the nutritional picture in industrialized versus traditional societies. One major factor that has differentiated these two broad camps until recently is the aggressive inclusion of industrially produced and toxic vegetable oils in every conceivable corner of the modern westernized diet. (Sadly, things seem to be changing for the worse elsewhere as well, as in India, where a “colorless revolution” is displacing native cold-pressed oils such as coconut, rape seed and sesame oils extracted with a stone press, with introduced foreign oils extracted with heat or solvents.5) Fallon and Enig observed that over the course of the twentieth century, beef consumption increased by 46 percent, but consumption of vegetable oils rose by a whopping 437 percent.4
Polyunsaturated fats such as corn oil and soybean oil are highly unstable and vulnerable to oxidation—and oxidation, in turn, is linked to cancer—while the omega-6 fatty acids that predominate in vegetable oils have been shown to accelerate the growth of tumor cells.6 As Fallon and Enig explain,4 excessive consumption of toxic polyunsaturated oils—not red meat—represents a known mechanism for colon cancer: “Colon cancer occurs when high levels of dietary vegetable oils and hydrogenated fats, along with certain carcinogens, are acted on by certain enzymes in the cells lining the colon, leading to tumor formation” [Emphasis added].
In short, meat-eating is not associated with cancer in traditional societies because modern polyunsaturated vegetable oils and carcinogenic additives are largely absent from traditional diets, which instead include ample saturated fats (important for stabilizing the proteins that fight tumors).7 In contrast, industrialized diets include numerous carcinogens, while consumption of commercial vegetable oils (and fear of saturated fats) run rampant.
In the context of these patterns of vegetable oil consumption, the regional disparities in colorectal cancer incidence mentioned above make complete sense. As author Chris Kresser observes, “Most Americans that eat red meat eat it with a huge bun made of white flour, with a serving or more of other refined carbohydrates (chips, fries, soda) cooked in rancid, industrially processed vegetable or seed oils.”8 Kresser reasonably asks, “How do we know that it’s the red meat—and not these other foods—that is causing the increase in cancer?”
CONSIDERING THE BIGGER PICTURE
In their respective critiques of the “processed-red-meat-causes-cancer” thesis, Kresser8 and blogger Zoë Harcombe9 both point out that the observational studies reviewed by the WHO have numerous methodological shortcomings. The studies that formed the basis of the WHO’s headline-grabbing conclusions ask dietary intake questions of dubious reliability, follow people over time without examining their full dietary and lifestyle picture, and then dredge around in the data, looking for decontextualized patterns. (As Harcombe dryly comments, “No pattern = no journal article, so look hard!”9)
In discussing the limited evidence for the “probable” link between red meat and colorectal cancer, the WHO itself concedes that it is not possible to rule out other explanations (which it helpfully describes as “chance, bias or confounding”).2 Harcombe agrees, arguing that even when studies strive to adjust statistically for baseline differences in relevant factors such as socioeconomic status, body mass index, physical activity, smoking status and diabetes, it is impossible to grapple fully with all the factors that differentiate “the couch potato” from “the paleo buff” (her ideal), or to take into account the “chasm” that separates fresh and traditionally preserved meats from modern manufactured meat products.9
WHAT ABOUT THE GUT?
Regular Wise Traditions readers who are attentive to the importance of gut health will not be surprised to learn that the gut microbiome likely influences the relationships between dietary factors, including red meat consumption, and cancer risk.8 These relationships are interesting, complex and not yet well understood. In fact, exactly how the gut microbiome “interacts with foods to produce health conditions” is considered a new and dynamic area for further research by individuals on all sides of the red meat-colon cancer debate.10 For example, researchers at Harvard Medical School are studying fecal samples to assess the impact of red meat intake on gut microbes and their byproducts, which the researchers speculate may influence “biological pathways associated with colorectal cancer and other digestive diseases.”11Such studies are sure to underscore the importance of a healthy gut microbiome in mitigating cancer risk, regardless of the specific hypotheses and conclusions about red meat consumption.
STICK WITH TRADITIONAL FOODS AND MEATS
The vegan crowd is undoubtedly celebrating the rise in meatless Thanksgivings this year, documented by a recent Yahoo! Food survey.12 Vegans probably also are ready to applaud the WHO’s efforts to reduce the appeal and consumption of red meat and processed meat. The WHO makes an anemic attempt to have it both ways—acknowledging the “known health benefits” of eating meat and admitting that consumption of red meat “has not been established as a cause of cancer” but nonetheless continuing to advise a limited intake of processed meat and red meat because of their links “to increased risks of death from heart disease, diabetes, and other illnesses.”2 Unfortunately, this longstanding and oft-repeated bias against red meat means that researchers who assert an association between red meat and cancer probably will continue to be assured of an enthusiastic reception, however poorly designed or lacking in context their studies may be.
Fortunately, thoughtful eaters accustomed to eating omnivorous, nutrient-rich diets—including braised red meat stews and home-cured bacon—are likely to be willing to dig beneath the headlines to make up their own minds.
1. International Agency for Research on Cancer. IARC Monographs evaluate consumption of red meat and processed meat. Press release no. 240. Lyon, France: World Health Organization, October 26, 2015. iarc.fr/en/media-centre/pr/2015/pdfs/pr240_E.pdf
2. World Health Organization. Q&A on the carcinogenicity of the consumption of red meat and processed meat. October 2015. who.int/features/qa/cancer-red-meat/en/
3. Haggar FA, Boushey RP. Colorectal cancer epidemiology: incidence, mortality, survival, and risk factors. Clin Colon Rectal Surg 2009;22(4):191-197. ncbi.nlm.nih.gov/pmc/articles/PMC2796096/
4. Fallon S, Enig MG. It’s the beef: myths and truths about beef. Wise Traditions, Spring 2000. westonaprice.org/health-topics/its-the-beef/
5. Sharma R. India’s colourless revolution: replacement of traditional oils by soy and palm oils. Independent Science News. May 12, 2008. independentsciencenews.org/health/indias-colourless-revolution-replacement-of-traditional-oils-by-soy-and-palm-oils/
6. Walling E. Polyunsaturated fats linked to higher cancer risk. Natural News. July 14, 2010. naturalnews.com/029194_cancer_risk_fats.html
7. Enig M. The importance of saturated fats for biological functions. Wise Traditions, Spring 2004. westonaprice.org/health-topics/the-importance-of-saturated-fats-for-biological-functions/
8. Kresser C. Red meat & cancer—again! Will it ever stop? Chris Kresser: Let’s Take Back Your Health—Starting Now. October 29, 2015. chriskresser.com/red-meat-cancer-again-will-it-ever-stop/
9. Harcombe Z. World Health Organisation, meat & cancer. Zoë Harcombe: Diet, Obesity, Nutrition & Big Business: So Much, So Wrong. October 26, 2015. zoeharcombe.com/2015/10/world-health-organisation-meat-cancer/
10. Kobayashi L. Red meat and cancer: the biological evidence. PLOS Blogs. November 17, 2014. blogs.plos.org/publichealth/2014/11/17/red-meat-biological-evidence/
11. American Gastroenterological Association. New gut microbiome research to explore red meat-colorectal cancer pathway. EurekAlert! May 18, 2013. eurekalert.org/pub_releases/2013-05/aga-ngm051613.php
12. Paley, Rachel Tepper. 12 things you love the most about Thanksgiving dinner. Yahoo! Food, November 17, 2015. yahoo.com/food/12-things-you-love-the-most-about-thanksgiving-125316691.html.
HOW COWS ARE HELPING THE PLANET
“Farting cows prompt twelve-year-olds to turn to vegetarianism” could be the startling headline in one sixth grade classroom, where passionate youngsters are ready to argue that “farting cows” are the harbingers of climate change doom. This belief is promulgated all over the Internet. For example, Dr. Neal Barnard (president of a vegan-diet-promoting nonprofit) argues that every last cow on the planet is “belching out methane.”1 Barnard’s proposed solution? “Eat grains, beans, and other plant foods directly, instead of feeding them to animals.”
The problem with this advice is that domesticated cows (and their wild ancestors) were not and are not designed to eat much grain. (As Joel Salatin comments, it runs contrary to nature’s framework to feed cows grain, fermented forage, or carrion, “even if it makes them grow faster, and even if they seem to like it.”2) The prevalence of abusive feedlot animal production systems should not obscure the basic fact that, “For most of human history, browsers and grazers…ate what we couldn’t eat—cellulose—and turned it into what we could—protein and fat.”3
Furthermore, methane is the product of plant breakdown, wherever it occurs—whether in the rumen of the cow or on the prairie, or in wetlands—in fact, wetlands are a major source of methane. And no one is blaming the millions if not billions of ruminants that formerly roamed the planet for climate change.
Why does it matter that cows are natural ruminants, ideally suited to digest high-cellulose-containing plants rather than pesticide-laden corn and soybeans? It matters because cows can help save the planet. According to Judith Schwartz in her discussion of “improbable ways of restoring soil to heal the earth,”4 holistic management of livestock can reverse desertification and restore land. Here’s how it works: domestic herbivores, when properly managed and allowed to graze, trample, “bunch” and move on, ensure soil cover and the establishment of new plants. In turn, “a broad swath of plants get a good nibbling but none are overgrazed nor over-rested.” These practices produce soil that is “healthy, diverse, and resilient,”3 while at the same time storing excess carbon dioxide in the soil.5 Perhaps if those sixth graders could regularly visit farms where suitable rotational grazing practices prevail, they might understand that greedy and unnatural industrial farming systems are more deserving of their indignation than cows.
1. Barnard, Neal. Cows—not coal—are the real climate change culprits. Huff Post Green: The Blog, June 24, 2014. huffingtonpost.com/neal-barnardmd/cowsnot-coalare-the-real-_b_5526979.html
2. Salatin, Joel. Holy Cows and Hog Heaven: The Food Buyer’s Guide to Farm Friendly Food. Swoope, VA: Polyface, Inc., 2004.
3. Keith, Lierre. The Vegetarian Myth: Food, Justice, and Sustainability. Crescent City, CA: Flashpoint Press, 2009.
4. Schwartz, Judith D. Cows Save the Planet and Other Improbable Ways of Restoring Soil to Heal the Earth. White River Junction, VT: Chelsea Green Publishing, 2013.
5. Fairlie, Simon. Maximizing soil carbon sequestration: carbon farming and rotational grazing. Mother Earth News, August 21, 2012. motherearthnews.com/homesteading-and-livestock/sustainable-farming/soil-carbon-sequestration-rotational-grazing-ze0z1208zkon.aspx