Cancer Risk of Conventional Versus Grass-Fed Red Meat

I heard from a number of people in response to my article, Does Eating Meat Cause Cancer?  Many were looking for a deeper dive, with added nuance on the subject, to answer questions such as: Is all meat created equal when it comes to malignant disease?

My original article covered what is now known linking red meat, mostly processed, to various cancer types. Intentionally, it neither differentiated how various meats are raised, fed, finished, and sourced, nor if they were fed antibiotics or growth hormones.

Discussion of leaner red meats like venison, bison, and ostrich (yes, ostrich is actually considered red meat) were also not covered in the article.

These topics are important to better understand and share, so I’ve consulted the medical literature to learn what is currently known about each.

Full Disclosure

I’ve explored these areas, not to try to convince you to eat a certain way.

Certainly, compelling work has been done regarding healing certain health conditions, specifically by including meat in the diet. The work of Terry Wahls, MD, in reversing MS and other neurodegenerative and autoimmune diseases with diet, is remarkable.[1] Also, Dr. Natasha Campbell-McBride, founder of the GAPS (Gut and Psychology Syndrome) diet and protocol, has reversed numerous health conditions using bone broth, among other animal products, to help heal the gut.[2] In addition, the research of doctors Weston A. Price, DDS, and Francis M. Pottenger Jr., MD, regarding a natural diet (including meat and dairy) and health have stood the test of time since the 1950s.[3]

Although we might want simple answers, people (with their particular health issues) may not be one-size-fits-all when it comes to diet. For example, the GAPS protocol lists different diets for different physiological types.

Those who have read my work over time know I am partial to the diet that has worked well for me for more than 25 years, which is plant-based and, specific to animal protein, includes only cold water, omega-rich fish and the occasional crustacean (my “cheat”).

This is the same diet I espouse for my coaching clients, sans the crustaceans. But I remain curious about, open to, and interested in, new dietary research, and I’ve approached it based on facts, not personal ideology.

I thought you might be curious about these topics, too.

Ready? Let’s dig in.

History of Humans and Meat Eating

Scientists believe that human beings have eaten meat for about 2.5 million years. In harsh regions, such as the Himalayan mountains, a yak to provide a family with wool, milk, and meat often meant the difference between life and death.

A change even more significant than when humans began eating meat, however, occurred when we began cooking it. Cooking meat began sometime between 1.8 million and 400,000 years ago.

[See Glenn Sabin’s Anticancer Foods List]

This processing, so Harvard primatologist Richard Wrangham believes, made meat softer and more easily digestible, thereby contributing more nutrition. The more energy-dense cooked food allowed for more children to thrive. He demonstrated his theory in the lab by feeding two groups of rats either raw or cooked meat and vegetables. The cooked-food group gained more weight—15 to 40 percent more.[4] Wrangham felt this evolutionary nutritional boost allowed humans to build bigger brains.

However, the above-referenced article makes a strong point that humans have gotten “too good” at food processing for our own good.

Nutritional Benefits of Red Meat

Meat is a nutritionally dense food source, containing high-quality amino acids (the building blocks of protein), vitamins A, B6, B12, D, E, and minerals, including iron, zinc, and selenium (all of which are important for health and the immune system).

Meat also contains numerous fatty acids. Cholesterol, of course, has been blamed for decades as the main contributor to skyrocketing rates of heart and cardiovascular disease.

However, not all researchers agree that meat is the culprit, just because it contains fat. Our brains are mostly composed of fats—60 percent, in fact.[5] Fats are also essential for our cell membranes and hormones.

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Dietary fats provide satiety and facilitate the absorption of the fat-soluble vitamins (A, D, E, and K). Some studies show that one type of fat in meat (stearic acid) has zero net impact on raising cholesterol levels and another type (oleic acid) actually reduces cholesterol in healthy populations.[6]

All Cows Are Not Created Equal

It turns out that how an animal is raised makes a huge difference in how healthy that meat is. It makes sense, and scientists have proven it.

Large-scale, commercially raised animals are crowded in confined areas, abbreviated CAFO, meaning concentrated animal feeding operation.

Due to the illness that results from the unnatural and stressful overcrowding, antibiotics and drugs are overused. Drugs cause more weight gain in the animals, but more weight means higher profits for the operation owners, so they approve.

Cattle, whose natural diet is grass, gain more weight when fed grain such as corn. American consumers have become accustomed to the fat color, marbling, and flavor of grain-fed beef.

Cows raised on grass their entire lives are leaner and their meat has a different color fat: It’s yellower, due to the natural carotenoids. Scientists wondered if grass-fed might be healthier to eat than grain-fed beef.

After studying both for thirty years, researchers noted that “several studies suggest that grass-based diets elevate precursors for vitamins A and E, as well as cancer fighting antioxidants such as glutathione (GT) and superoxide dismutase (SOD).” Further, grass-fed beef consistently showed higher concentrations of omega-3 fatty acids, as compared to grain-fed contemporaries, creating a more favorable ratio between omega-6 and omega-3.[7]

“A more favorable ratio” is an understatement. When compared to feedlot, grain-fed beef, naturally raised grass-fed meat contains three times more omega-3, seven times more vitamin A, and ten times more vitamin E. Grass-fed beef is also significantly higher in carotenoids and other antioxidants, and is lower in total fat and calories.[8], [9]

Corn-fed beef—which is likely GMO corn, by the way—has 20 times more omega-6 fatty acids. Although omega-6 fats are necessary in the right amounts, Americans get far too many (for example, from corn, soy, and safflower oils). Omega-6 fatty acids, when in the wrong ratio to omega-3, are linked to higher rates of arthritis, chronic inflammation, and cancer.[10]

Meat also contains conjugated linoleic acid (CLA), which has gained a reputation for reducing (human) body fat and improving the glucose profile, atherosclerosis, bone density, and as an anti-cancer nutrient.[11] Researchers are encouraged by links that seem to indicate a positive effect of CLA on some types of cancer, including small cell lung and breast cancers.[12], [13]

Interestingly, CLA is also an omega-6 fatty acid, yet it has health benefits that may differ from those in refined vegetable oils. CLA levels are higher (often twice as high) in grass-fed versus grain-fed meat. Why?

It’s all about how the animals are raised. Our food system has adopted mass production, efficiency, and economies of scale (with a heavy reliance on antibiotics). In general, we produce meat for quantity, not quality.

And our dismal overall health as a nation reflects that.

What About Wild Meats?

What if we could turn back the clock and return to the way our hunter-gatherer ancestors ate?

It is difficult to locate studies comparing the health effects of (specifically) wild meats versus conventional, because, logically, who would pay for them? However, I did find this study that suggested bison is a healthier alternative to beef.[14]

This 2019 study explores the question of whether raising ruminants on their natural grass diet is healthier for people and the planet. The abstract wisely concludes that we are members of natural communities, and by nurturing them, we nurture ourselves.[15]

Also, this resource is loaded with scientific studies gathered around grass-fed versus conventionally raised meats.[16]

The wild meats, such as bison, yak, ostrich, venison, and elk are grass fed or “free range.” I’m sure a whole article could be written examining the nutritional compositions of each (and the USDA is a good source for that, if you’re interested).

But for the purposes of this article, here are some generalizations about wilder types of meat. The animals are:

  1. Raised in more natural, less crowded, and more humane conditions on small family farms
  2. Fed diets that are natural to their species
  3. Lower in fat and higher in protein
  4. Marketed to savvy, health-conscious consumers, so they are unlikely to have any growth hormones or antibiotics administered

One thing I found interesting is that because yak evolved in the highest mountain regions on earth, their red blood cells are much smaller than those of mammals in the more temperate regions. This smaller size allows the yak blood to carry three times more oxygen (via iron) to the animal’s tissues in that high altitude. The higher iron content also makes yak meat much redder.

Many of you may see “iron” and have red flags (no pun intended) go up regarding cancer. As I discussed in my previous article, many studies link red meat to colorectal cancer, and “heme” (from blood) iron was fingered as the probable bad guy.[17]

Remember this in the new context of what type of meat was studied: Undoubtably, it was mass-produced, “factory farmed” meat. So, of course, we can imagine that meat could cause cancer, especially if the animals were loaded up with antibiotics and growth hormones to increase weight (increasing profits), and the meat was then preserved with nitrates, grilled, or charbroiled (all of which raise the carcinogenic potential).

However, other studies show that if antioxidant levels are high (for example, from eating lots of fresh fruits and vegetables), the carcinogenic potential of iron (even in commercial meat) can be mitigated.[18], [19]

What About the Planet?

Environmental experts tell us that eating meat is destroying the earth. They point to methane gas increases in the atmosphere and say that cattle are to blame. Perhaps so, if looking at CAFOs.

Commercial beef operations and slaughterhouses with their feedlot “grain-finishing” practices are horrific. As the cattle are crowded together to be fattened up on drugs[20] and junk food before slaughter, the animals try to stand up out of the disgusting muck on huge mountains of manure.[21]

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But this is not the only way cows can be raised. Cattle can be raised in humane ways. And as many have proven, grazing animals can actually improve the land and the environment.

“Only livestock can save us,” says Allan Savory, a research biologist and the pioneer and guru of holistic management and managed grazing from the Africa Centre for Holistic Management (ACHM) in Zimbabwe. He has proven that livestock improve dry, desert-like wasteland, whereas the notion of removing livestock to “rest the land” actually degrades it.[22] Healthy soil and land captures and sequesters excess carbon dioxide, keeping it out of the atmosphere.

This has also been proven in the U.S. (and tirelessly promoted) by Joel Salatin, farmer, author, and owner of Polyface Farms. When describing experts who argue that eating meat is killing us and our planet, he says they don’t realize that “every pork chop is not the same, every egg is not the same, and every tomato is not the same.” How our food is raised has everything to do with how it nourishes our body, our society, and our world.[23]

As just one example, his farm participated in a study that investigated the level of folic acid, a vital nutrient for pregnant women, in chicken eggs. The USDA measured 48 mcg of folic acid in a commercially raised hen’s egg. The Polyface Farms egg, from a pasture-raised chicken, contained 1,038 mcg of folic acid! And there were similar deviations in the levels of B vitamins and other nutrients—not just ten percent higher nutrition, but sometimes a thousand percent more.

Salatin regards conjugated linoleic acid (CLA) as one of the top anticarcinogenic substances in nature. Cows are ruminants. They were designed to eat grass, not grain. As mentioned above, the CLA in grass-fed cows is much higher than grain-fed cows, and Salatin explains why.

“After only fourteen days of grain-feeding … the CLA is gone.”

Keep in mind that “grain-feeding” is much worse than it sounds. Large cattle operations feed the cows not only inflammatory, glyphosate-loaded GMO grains, but also such things as municipal sewage, food industry waste like old candy (including wrappers),[24] fecal waste from cattle, swine, and poultry,[25], [26], [27] plastic pot scrubbers (for fiber!),[28] newspaper (with all of its toxins),[29] sawdust,[30] animal byproducts like blood meal, meat, chicken, and feathers,[31], [32] and the horrendous list goes on and on.

Is it any wonder that feedlot cows are suffering and profoundly sick? Is it any wonder that our fast-food nation is?

A wonderful alternative: Shop farmers’ markets, join a CSA (community supported agriculture), and meet your local farmers. Family farm-raised produce and meats provide higher nutrition, benefit the environment, and benefit communities—what’s not to love?

I can hear you: “But it costs more!” Maybe.

But consider the true costs and benefits.

The True Costs of Cheap Food

Doctor of veterinary medicine Will Winter says, in his excellent piece[33] published by the Weston A. Price Foundation, that a better question to ask is: “Why does feedlot beef appear to be so cheap?”

He explains why in detail, then states that when evaluating the true costs of commercial, feedlot meat—with its devastating environmental pollution, animal cruelty, inherent lack of sanitation, antibiotics and other drugs (within the animal and the meat), which causes inflammation (arguably the root cause of practically every disease) in those who eat it—when we truly see the whole picture, feedlot meat is the most expensive of all.[34]

Salatin echoes this. He points out that processed food is really what’s expensive. For the average price of one fast-food combo meal, you could buy a whole pound of his grass-fed ground beef, and feed several people. It’s simply a matter of priorities … and convenience.

Although, if you get down to it, no one can argue against a slow cooker, which offers a healthy and convenient way to cook meats and soups. And a food processor is an amazing appliance to quickly prep all your veggies.

So, in reality, it’s just a matter of changing our habits.

Changing for the Better

In general, we have outsourced our food processing for convenience. We want to be able to eat on a moment’s notice so we can get on with “more important things.”

Big Food is happy to step in. Their marketing relentlessly pushes people toward ill health, beginning with ads for children’s artificially colored and sugar-laden cereals, and continuing through adulthood with ads for chemically laden and deep-fried (in GMO and inflammatory oils) fast food, and super-sweet lattes.

Real, natural fats and proteins satisfy hunger and convey health; fresh herbs and vegetables (always choose organic for produce on the EWG’s Dirty Dozen list) taste amazing and provide vitamins, minerals and fiber; real fruit is naturally sweet and also provides nutrition and fiber.

Most importantly, real food conveys real health. Mass-produced, chemically laden “food” never will.

It may take a little effort to “change the channel” of your long-standing food habits and become your own food processor. Committing to your health might require preparing health-promoting food in your own kitchen. You can even make it fun, if you decide to…

It may not be quite as convenient. But I’m here to tell you, firsthand, it’s worth it.

The Bottom Line

If you decide to consume red meat—or any animal protein for that matter—invest in quality, well-sourced, “healthier” products. Prepare your food in a healthy manner. And eat (even healthy and properly prepared) animal protein in moderation, to complement a heaping plate of bountiful fruits and vegetables.

This isn’t personal ideology; it’s based on the published science—and it just makes good sense.

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[7] Ibid.



[10] Ibid.










[20] Number 7.

[21] Number 6.



[24] Wolf, B. W., L. L. Berger, and G. C. Fahey, Jr. “Effects of Feeding a Return Chewing Gum/Packaging Material Mixture on Performance and Carcass Characteristics of Feedlot Cattle.” J Anim Sci 74, no. 11 (1996): 2559-65.

[25] Gilka, J., J. Bartos, V. Gajduskova, M. Malikova, J. Masek, J. Sic, and Z. Matyas. “Foreign Substances in the Meat and Organs of Bulls Fed on a Diet of Swine and Poultry Fecal Waste.” Vet Med (Praha) 26, no. 11 (1981): 651-60.

[26] Rankins, D. L., Jr., M. H. Poore, D. J. Capucille, and G. M. Rogers. “Recycled Poultry Bedding as Cattle Feed.” Vet Clin North Am Food Anim Pract 18, no. 2 (2002): 253-66.

[27] Tokarnia, C. H., J. Dobereiner, P. V. Peixoto, and S. S. Moraes. “Outbreak of Copper Poisoning in Cattle Fed Poultry Litter.” Vet Hum Toxicol 42, no. 2 (2000): 92-5.

[28] Loerch, S. C. “Efficacy of Plastic Pot Scrubbers as a Replacement for Roughage in High- Concentrate Cattle Diets.” J Anim Sci 69, no. 6 (1991): 2321-8.

[29] Mertens, D. R., J. R. Campbell, F. A. Martz, and E. S. Hilderbrand. “Lactational and Ruminal Response of Dairy Cows to Ten and Twenty Percent Dietary Newspaper.” J Dairy Sci 54, no. 5 (1971): 667-72.

[30] Dinius, D.A. “Sawdust as a Diluent for Adapting Cattle to Concentrate Diet.” J Anim Sci 41, no. 4 (1975): 1170-79.

[31] King’ori, A. M., J. K. Tuitoek, and H. K. Muiruri. “Comparison of Fermented Dried Blood Meal and Cooked Dried Blood Meal as Protein Supplements for Growing Pigs.” Trop Anim Health Prod 30, no. 3 (1998): 191-6.

[32] Mantysaari, P. E., C. J. Sniffen, T. V. Muscato, J. M. Lynch, and D. M. Barbano. “Performance of Cows in Early Lactation Fed Isonitrogenous Diets Containing Soybean Meal or Animal by-Product Meals.” J Dairy Sci 72, no. 11 (1989): 2958-67. [In this 1989 study, animal by-products given to the milk cows included meat and bone meal, blood, chicken, and feathers.]


[34] Ibid.