The Many Benefits of Grass-Fed Beef

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Caveman Doctor recently traveled to a foreign country to celebrate his brother’s wedding. It was an amazing event, taking place in his fiancé’s hometown. Immediately after catching a cab at the airport to his cave hotel, the cabbie started talking food with him. Actually, he started talking beef. This fortuitous coincidence was unprovoked mind you, but he did pick the right audience. Caveman Doctor started questioning him about local beef-raising habits. He went into a rant about how some cows at higher elevations eat grass that is juicier, providing a slightly lighter-tasting steak, while those at lower altitudes eat dryer and fuller grass, providing the meat more of an earthy taste. Caveman Doctor had no clue if what he was saying was true, but he was very intrigued. The cabbie was also swerving all over the road, so admittedly Caveman Doc was having trouble paying close attention.


Grass-Fed Beef

Amazingly, this cab driver appeared to know more about grass-fed beef than 99% of the nutritionists and health experts I talk to in the United States. I asked him how often cows are fed grains. He laughed out loud, and with a deep accent said, “Unlike you Americans, we do not stuff our cows’ faces with corn and grains, giving them disease, intestinal problems, and meat full of fat. We enjoy the meat as though it is supposed to be enjoyed – tasty and lean.” I was extremely impressed with his knowledge and followed his recommendations for meals for the rest of the trip, including the Cabrito.
In fact, for the rest of the trip I ate grass-fed beef on a daily basis. It was the first wedding in my life that had grass-fed beef for the guests (It was also the first wedding in my life that went until 6 a.m. too). I did a little examining myself and saw nothing but free-roaming cows in the pastures as well.
So where is this exotic place: Spain? France? Italy?

With my caveman brother, celebrating his wedding (and grass-fed beef).

Try again. It was our neighbor to the south.


I actually did a little research and my cabbie was likely telling the truth. Cow feeding in Mexico varies, but judging by my examination of the beef, and the local beef ranches, it appears as though the beef was actually grass-fed. Up here in the States, we take a lot of shots at Mexico, but judging by my trip, we have a few things to learn from them. The people there are extremely friendly and courteous, there was a real sense of family and community, and most of their beef is grass-fed! Well, at least in parts of Monterrey.

Why Are so Many Cattle in the U.S. Grain-fed?

The simple answer is that the price of grains has been artificially lowered by our trusty government, making it appear cheaper to stuff cows together in small places, then proceed to stuff their faces with corn, soy, and other barely digestible items (I can’t even refer to them as food). These confined animal feeding operations (CAFOs) apparently save billions of dollars on animal feed from these government subsidies and the Congressional Budget Office estimates that 7.3 billion dollars came out of our taxes to pay for cattle feed. However, as many of you may have seen in the recent documentary “Fresh”, overall societal cost and burden is much greater.

So Why Not Just Support Government Subsidies and Eat Grain-Stuffed Beef?

While this is by no means a political website as organized politics was not around for most of Caveman Doctor’s existence and even if they were he would have ignored the valueless banter (can you guess my point of view?), the issue of government subsidies must be addressed so we can even understand why cows are fed corn and grains. Many people think that we are paying for it whether we like it or not through our taxes which we have little control over, so we might as well swallow it. I beg to differ.
As we discussed in previous posts, when cows eat grass and other foods, it sits in their rumen and ferments as cud. The bacteria in the rumen then eat this fermented sludge and the cows digest the bacteria. Grass leads to a favorable environment for bacteria to grow in the rumen and ferment, leaving a healthier rumen for more grass in the future, which makes sense as these foods have been sitting in cows’ rumens for millions of years and they are biologically (and evolutionarily if you like) adjusted to such foods. When their rumen is filled instead with acid-causing unnatural grains, the bacteria don’t do their job as well.
Though products like corn and soy use an incredibly large amount of land, and require artificial irrigation and mega-amounts of pesticides, government subsidies have artificially driven the price of these products so low that they are remarkably cheap to use as cow feed. Cotton seed mill is often used as it is even cheaper than corn and soy mill. It is now cheaper for some farmers to tear down fractions of our entire country to grow unhealthy soybean, corn, and other grains, wrecking the land (and our health) in the meantime.
I wish we could stop here and all I had to tell you is that cows are fed pesticide-laden modern plants that they weren’t meant to eat (corn, soy, etc). However, it’s worse. Too often these animals are fed industrial feed that includes antibiotics, more pesticides, hormones, manure, and even meat from other animals (often diseased) including blood, skin, and hooves. Feeding cows the ground bodies of diseased cows, including their brains and other organs, is likely what led to the mad cow disease epidemic1,2Frankly, even a caveman would think it is unwise to feed cows other cows that dropped dead from disease, but these are the things that go on in this disgusting industry. While new laws prohibit feeding animal parts to cows and ruminants, it persists in pigs, chicken, and other poultry.
Since cows are not made to eat and digest these grains much less each other, they develop severe medical issues, including digestive, respiratory and metabolic disease3, similar to when humans consume foods they aren’t made to eat and digest (even a caveman can see these patterns…). In fact, feeding cows these unnatural diets causes a syndrome known as “fat cow disease”. This rather unimaginative but aptly named disease results in depression, progressive debilitation, weakness, nervous signs, and a febrile state from chronic elevation in temperature due to infections4.
Since cows are also packed into close corridors and end up relieving themselves in these tight spaces, their feces often makes its way into their food, causing significant contamination by bacteria5. To combat the infection and disease, antibiotics must be used, which is causing antibiotic resistant strains of Salmonella and E. Coli to increase in prevalence. In fact, up to 60% of cattle feed is contaminated with salmonella6! These are the same infections that would cause a patient to be placed in isolation in the hospital, yet we are feeding it to our cows! Cows need to roam the pasture, where their excrement can be used as fertilizer in an open pasture, to actually help the environment, not as a carrier or infections and disease.

Here are some common animals and their sources of nourishment:


1.      Cows: grass
2.      Chickens/turkeys: bugs, worms, plants
3.      Pigs: grass, plants

So why would we feed them grains like soy and corn, along with pesticides and hormones? Oh yeah, I forgot about the whole subsidies thing above… The following discussion reviews the main health benefits of eating grass-fed and grass-finished beef, also known as pastured-beef. These benefits include only cows that are allowed to roam the pasture eating grass throughout their entire life, and not grain-finished cows!

Which Cows Look Happier and Healthier?


Image by graur razvan ionut /

Image by: dan /

Image by: dan /


Omega-3 Fatty Acids

For millions of years, the caveman ate roughly a 1:1 or 2:1 ratio of omega-6 to omega-3 fatty acids.  Omega refers to the point on the fatty acid backbone where the double-bond lies, as discussed in Vegetable Oils: The Refining of our Health. However, nowadays we eat over a 15:17 ratio due to an overconsumption of many unhealthy foods, with the bulk of the blame on resting on vegetable oils.
The benefits of omega-3s were first realized from our modern-day caveman up north, the Inuit Eskimos. This same group that rarely got cancer, also rarely had heart disease even though they ate enormous amounts of fat. Besides sugar, grains, and insulin, lack of consumption of omega-3s is likely one of the most damaging influences on our health. In fact, a high ratio of omega-6/omega-3 fats has been associated with increased risk of cancer, cardiovascular disease, asthma, and autoimmune disease.8 As we have already discussed at length in the CLA and vegetable oil article, linoleic acid, which is used to cause cancer, is an omega-6 fatty acid. Population studies have shown that omega-3s in the diet, like fish oil, work counter to omega-6s and reduce the risk of prostate cancer.9,10 Randomized trials have shown that omega-3s lower those inflammatory markers like IL-6 that can rising during stress11 (see here, and here , and the anti-inflammatory benefits likely play a big part in the reduction of cancer risk. In simple terms, omega-3s are anti-inflammatory and omega-6s can cause inflammation, resulting in a multitude of diseases.  Interestingly, when women at high risk for breast cancer were given large amounts of the omega-3, they actually store it in their breast tissue, similar to CLA.12 It’s no wonder it can reduce the risk of breast cancer. The message is clear, generally more omega-3s and less omega-6s is the pathway to good health.
So do grass-fed cows have more omega-3 in their meat?  Of course they do, because that is what happens when we follow Mother Nature’s master plan. Why would She make the foods that we are naturally supposed to eat result in poor health? In fact, when the meat of wild ruminants roaming the forest, eating Nature’s best offerings is examined, it contains a near 1:1 to 2:1 ratio of omega-6 to omega-3 fatty acids – similar to the one that Caveman Doctor ate in his time. This ratio is also remarkably similar to that of pasture-raised cattle13. Also, when pastured (i.e., grass-fed) beef and grain-fed beef are compared, the grass-fed cows have 4 times the omega-3s in their meat14! When we can’t get our hands on wild animals, it looks like grass-fed (and grass-finished) cows are just as good of an option.

Conjugated Linoleic Acid


As we have already discussed, the potential benefits of CLA include:


1.      Decreased risk of cancer
2.      Slowed cancer progression15
3.      Decreased body fat
4.      Increased muscle mass
5.      Decreased atherosclerosis
6.      Lower insulin levels
7.      Improved glucose tolerance

Meat from cattle fed all-grass diets, as opposed to grain-fed beef, has significantly more CLA and vaccenic acid (the precursor to CLA).16 Also, as CLA is synthesized in the rumen of cows, a hospitable, non-acidic environment is needed to turn the vaccenic acid into CLA.17 As grains increase the amount of acid in the rumen, this can only be accomplished through feeding cows grass, which leads to increased production of CLA – actually, 2-3 times more CLA!16,18  Studies actually show that the amount of CLA and the omega-3s in beef are directly proportional to the amount of grass a cow eats.19

Vitamins, Minerals, and Antioxidants

Beef provides a large source of minerals, such as iron, zinc, and selenium, and vitamins, including folic acid and vitamin A, B6, B12, D, and, E.20 Also, many of these vitamins and minerals are not present or are poorly bioavailable in plant sources.21
As you will easily see when comparing the fat of grain-fed and grass-fed meat, the grass-fed beef fat has a more yellowish color than the pale color of grain-fed meat fat. What many don’t realize is that this color is actually from the carotenoids in the green grass. Carotenoids, which are precursors to vitamin A, are what give grass and other fruits and vegetables their bold color. Some people don’t like this color, and that is easily fixed by feeding the cows grains, with their relative deficiency of antioxidants and carotenoids22. Interestingly, many cattle farms feed cows grass for most of their life, then quickly fatten them up by feeding them grains over a couple of weeks. This short process actually quickly changes the color of their fat, as the antioxidant-rich fat is quickly replaced with nutrient-stripped fat.
Pastured (again, grass-fed) beef also contains seven times more antioxidants than grain-fed beef.16 In fact, when compared with grain-fed beef, pastured beef has significantly higher amounts of vitamin C, vitamin E, and beta-carotene.23 This can’t even be corrected by feeding the cows more vitamins with their grains, as studies show that even when supplementing their diets with vitamins and antioxidants, analysis of beef from grass-fed beef still has more vitamins, minerals, and antioxidants. Once again, the way in which Mother Nature created it is the way she wants it. Cows are supposed to roam fields openly and eat grass. Giving them vitamins won’t make up for their unnatural diet – Mother Nature can’t be fooled!
Glutathione, which is a free-radical scavenger in your body, renders free-radicals no longer reactive, eliminating their potential damage. It is found in high levels in leafy green vegetables, which is why experts often quote the cancer-fighting powers of these vegetables. While this credit is well-deserved, what you often don’t hear is that beef contains relatively high amounts of glutathione as well16. And no surprise, grass-fed beef contains significantly more of this antioxidant than its grain-fed contemporary24.
Conversely, reactive free-radical substances that antioxidants help protect us from are significantly higher in grain-fed beef23. Part of the increase in free radicals in their meat is likely from the stressful conditions they are raised in (close quarters, an unnatural diet, a high rates of infections, depression, etc.), as the stress likely causes a heavy and constant release of inflammatory chemicals in these cows, like it does in humansNot only does grass-fed beef from pastured cows provide us with more antioxidants to fight free-radical damage, but it has much less free radicals to cause damage! Also, just as vegetable oils can be overtaken by free radicals during shelf life, beef is no different. Having your beef full of as many antioxidants as possible will help it fight the constant attack by free radicals as it sits in your fridge or at the butcher24.

In summary, there are many direct benefits of grass-fed beef:


1.      Increased amounts of disease- and cancer-fighting CLA
2.      Higher ratio of omega-3:omega-6 fatty acids
3.      Increased amounts of vitamins A, C, and E
4.      Decreased amounts free-radicals
5.      A more ethical treatment of animals
6.      A less stressful environment
7.      Less toxic damage to the environment
8.      Less production of antibiotic-resistant bacteria


Which lead to the following health benefits:


1.      Decreased risk of cancer
2.      Decreased cancer progression once diagnosed
3.      Decreased body fat
4.      Increased lean-muscle mass
5.      Decreased atherosclerosis
6.      Lower insulin levels
7.      Improved glucose tolerance
8.      Decreased heart disease
9.      Decreased autoimmune disease
10.   Decreased asthma
11.   Decreased inflammation

Frankly, this list could go on and on… The benefits of grass-fed beef are plentiful. The fat in grass-fed beef is not even comparable to that of grain-fed beef. In the words of the famous nutrition researcher David Kritchevsky, who did most of his work at the Wistar Institute, across the river from me in Philadelphia25:

“Animal fat, which has been maligned for so long, may actually contribute a potent therapeutic component to our diet.”

I think if he were still alive, Kritchevsky would gladly add “grass-fed” to the beginning of this quote.

In Conclusion

Make the right choice for cows, for your own health, for responsible government spending, and for our environment, and do what the caveman did: go grass-fed!



1. d’Aignaux JN, Cousens SN, Smith PG: Predictability of the UK variant Creutzfeldt-Jakob disease epidemic. Science 294:1729-31, 2001

2. Ramasamy I, Law M, Collins S, et al: Organ distribution of prion proteins in variant Creutzfeldt-Jakob disease. The Lancet infectious diseases 3:214-22, 2003

3. Smith RA: Impact of disease on feedlot performance: a review. Journal of Animal Science 76:272-274, 1998

4. David A M: Fat Cow Syndrome. Journal of dairy science 59:1625-1629, 1976

5. Crump JA, Griffin PM, Angulo FJ: Bacterial Contamination of Animal Feed and Its Relationship to Human Foodborne Illness. Clinical Infectious Diseases 35:859-865, 2002

6. Kidd RS, Rossignol AM, Gamroth MJ: Salmonella and other Enterobacteriaceae in dairy-cow feed ingredients: antimicrobial resistance in western Oregon. Journal of environmental health 64:9-16, 32; quiz 35-6, 2002

7. A.P S: The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomedicine & Pharmacotherapy 56:365-379, 2002

8. Simopoulos AP: Omega-3 Fatty Acids in Inflammation and Autoimmune Diseases. Journal of the American College of Nutrition 21:495-505, 2002

9. Norrish AE, Skeaff CM, Arribas GL, et al: Prostate cancer risk and consumption of fish oils: a dietary biomarker-based case-control study. British journal of cancer 81:1238-42, 1999

10. Terry P, Lichtenstein P, Feychting M, et al: Fatty fish consumption and risk of prostate cancer. Lancet 357:1764-6, 2001

11. Vedin I, Cederholm T, Freund Levi Y, et al: Effects of docosahexaenoic acid–rich n–3 fatty acid supplementation on cytokine release from blood mononuclear leukocytes: the OmegAD study. The American journal of clinical nutrition 87:1616-1622, 2008

12. Yee LD, Lester JL, Cole RM, et al: ω-3 Fatty acid supplements in women at high risk of breast cancer have dose-dependent effects on breast adipose tissue fatty acid composition. The American journal of clinical nutrition 91:1185-1194, 2010

13. Cordain L, Watkins BA, Florant GL, et al: Fatty acid analysis of wild ruminant tissues: evolutionary implications for reducing diet-related chronic disease. European journal of clinical nutrition 56:181-91, 2002

14. Nuernberg K, Nuernberg G, Ender K, et al: N-3 fatty acids and conjugated linoleic acids of longissimus muscle in beef cattle. European Journal of Lipid Science and Technology 104:463-471, 2002

15. Ip C, Briggs SP, Haegele AD, et al: The efficacy of conjugated linoleic acid in mammary cancer prevention is independent of the level or type of fat in the diet. Carcinogenesis 17:1045-1050, 1996

16. Daley C, Abbott A, Doyle P, et al: A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. Nutrition Journal 9:10, 2010

17. Bessa RJB, Santos-Silva J, Ribeiro JMR, et al: Reticulo-rumen biohydrogenation and the enrichment of ruminant edible products with linoleic acid conjugated isomers. Livestock Production Science 63:201-211, 2000

18. Realini CE, Duckett SK, Brito GW, et al: Effect of pasture vs. concentrate feeding with or without antioxidants on carcass characteristics, fatty acid composition, and quality of Uruguayan beef. Meat Science 66:567-577, 2004

19. French P, Stanton C, Lawless F, et al: Fatty acid composition, including conjugated linoleic acid, of intramuscular fat from steers offered grazed grass, grass silage, or concentrate-based diets. Journal of Animal Science 78:2849-2855, 2000

20. Williamson CS, Foster RK, Stanner SA, et al: Red meat in the diet. Nutrition Bulletin 30:323-355, 2005

21. H.-K B: Meat as a component of a healthy diet – are there any risks or benefits if meat is avoided in the diet? Meat Science 70:509-524, 2005

22. Dunne PG, Monahan FJ, O’Mara FP, et al: Colour of bovine subcutaneous adipose tissue: A review of contributory factors, associations with carcass and meat quality and its potential utility in authentication of dietary history. Meat Science 81:28-45, 2009

23. Descalzo AM, Insani EM, Biolatto A, et al: Influence of pasture or grain-based diets supplemented with vitamin E on antioxidant/oxidative balance of Argentine beef. Meat Science 70:35-44, 2005

24. Descalzo AM, Sancho AM: A review of natural antioxidants and their effects on oxidative status, odor and quality of fresh beef produced in Argentina. Meat Science 79:423-436, 2008

25. Kritchevsky D: Antimutagenic and some other effects of conjugated linoleic acid. The British journal of nutrition 83:459-65, 2000
© 2015 CDR Health and Nutrition, LLC. All Rights Reserved.


  1. Diane and Tom

    What about grass fed during the winter months in northern climates? I’ve already seen disclaimers on cartons of eggs at Whole Foods and having grown up on a farm, I know farm animals don’t get green grass under the snow. It is very difficult to obtain fresh grass fed beef year round. 🙁

    1. cavemandoctor (Post author)

      Great point (as always). So some farms feed anything from hay to fermented alfalfa. I agree that this becomes harder to find local meat. I definitely stock up in late fall and sometimes purchase beef from South America. That being said, I was in the countryside in Holland this year for New Years and there were definitely cows out on the pasture, so I think if we can get a little grass in and then some hay, it’s still better than any feeds (though this obviously isn’t my area of specialty…). Eggs are definitely a whole different story as the local farmers I have talked to said their grain usage goes way up in the winter. Hydroponics may be one way to avoid this with worms, etc. Maybe we should eat up spring through fall and then hibernate in the winter to avoid these issues???!


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  4. JT

    Hi Caveman Doctor,
    I agree with you that processed foods, sugar, and carbohydrates are link to diseases. However, I would also like to point out that the average American does not have the resources or easy access to organic foods, grass fed beef, or unprocessed foods. For instance there’s no Wholefoods in my neighborhood. I don’t even know where to get grass fed beef. Most people are not going to go out of their way to get unprocessed foods if is too difficult to get it.
    I don’t have the solution to this..I just wanted to say it 🙂

    Thank you for making a difference by writing about nutrition!

    1. cavemandoctor (Post author)


      Thanks for the comments! I absolutely agree with the accessibility issues of grass-fed and other organic foods and am working on ways to find resources for my readers to easily find healthier food options (and to make them more affordable). Stay tuned!


      1. Jilly90

        I really admired your efforts to help your readers by finding resources, but after watching Fresh it seems to me that the root of the problem is our government not lack of resources. What are your thoughts on this matter?

        1. cavemandoctor (Post author)

          I agree 100%. Grain subsidies by our government resulted in stuffing our cows full of corn and soybean, making them fat and unhealthy, and the food pyramid resulted in people stuffing their faces with grains, and making them fat and unhealthy.

          Part of the struggle now is to undo the wrong thought process after years of wrong information, teach people how to be healthy, and then direct them to the right places (which hopefully become more and more common). Unfortunately, there are definitely areas of the country where it is very difficult to get a variety of healthy foods (I am visiting one as I type this).

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  7. Nick

    Great work CD! I’ve wondered about this type of winter feeding and what you might think of it:

    “Our winter forage is about one third corn silage and two-thirds grass silage. Silage is forage that is compressed to remove oxygen and then naturally ensiled, like our Sauerkraut. Grass/alfalfa silage has good protein but not enough energy for good growth. In this area corn grain is grown with corn seed having an 83 to 90 day maturity. By using 110 day maturing corn and then feeding cows the entire plant, not just the grain, we avoid the problem of unhealthy Omega 6 fatty acids in beef. The industry calls it “corn grass.” A corn plant is a grass that produces sugars through the summer, and only at the end of its life concentrates carbohydrates and oils in the grain. We harvest the corn while it is still too young for mature grain.”

    Thanks again for the terrific site!

    1. cavemandoctor (Post author)

      Hi Nick, winter feeds get tough to stay “grass-fed” or hay-fed which often happens. I am not sold on this as they are still getting the corn and grain, just with the green part as well. Seems like some sleight of hand going on…

  8. kaxxina

    “In fact, when the meat of wild ruminants roaming the forest, eating Nature’s best offerings is examined, it contains a near 1:1 to 2:1 ratio of omega-6 to omega-3 fatty acids – similar to the one that Caveman Doctor ate in his time. This ratio is also remarkably similar to that of pasture-raised cattle.”

    Shouldn’t the “omega-6” and “omega-3” above be swapped? I thought pasture-raised cattle had more omega-3s, not omega-6s…..

    1. cavemandoctor (Post author)

      Hi, no that is correct. Most foods are heavier in omega 3, having the balance closer to 1:1 is the goal and pastured beef approaches this.

  9. Gwenael

    Very interesting article indeed. I run a restaurant in Guadalajara, Mexico, and actually cannot find grass-fed beef here, it is a struggle as for some reason the gastronomic culture in this part of the country is almost non-existent. Would you have any details of a good grass-feeding farm in Monterrey (or anywhere close to Guadalajara), I would love to be able to make burgers with that meat.


    1. cavemandoctor (Post author)

      Thanks Gwenael! Off the top of my head, I do not. I will ask my sister-in-law and get back to you.

      Take care!

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