Friday, May 20, 2011

Is The Grass(-finished beef) Always Greener?

Two years ago, I would have never written what you’re about to read. I was so convinced that “you are what you eat and you are what you eat, eats” that I not only assumed, but willed for the absolute superiority of grass-finished over conventional beef. I scoffed at the scientists and lecturers that disagreed with my thoughts in defense of conventional beef production. I inspected hairline fractures in their arguments while I leaped over logic gaps to follow “food revolutionists”.

After completing my studies in beef cattle nutrition, I have found that, frankly, the good news I used to hear about grass-finished beef is not all that great, and the bad news about conventional beef is not all that bad. Although I respect niche-market cattlemen for their creation of an artisanal product—I really am particularly fond of the grass-finished taste—I can finally admit that whatever you and I have heard from a handful of avant-garde critics about ecological and nutritional superiority is…hype.

USDA defines “Grass-Fed” as the product of animals whose diet is solely forage-based, without any inclusion of grain. I’m using the term “Grass-Finished” because all cattle, no matter the system, are reared on their grass-consuming mother’s milk and eat forage until the “finishing” stage that brings them up to harvest weight. They either remain on pasture and keep eating forage or enter a feedlot and consume a mixed diet of corn, grain and oilseed by-products, and preserved forages like alfalfa hay or silage. I’ll refer you to Anne Burkholder’s blog if you’d like to know more about how a feedyard is managed.  

Nutrition Facts
While studying ruminant nutrition, I learned that “you are what you eat” somewhat applies to humans and other monogastrics (pigs, horses, etc.), but not quite as much to ruminants. Sort of in the same way milk cultures in to yogurt, ruminants use microbes to “culture”, or ferment, their diet into metabolic intermediates (volatile fatty acids…like lactic acid in yogurt) and microbial bodies (microbial crude protein…like what most of yogurt consists of). What a cow actually digests is much different than what she originally ingests. That helps explain…

1.      Omega 3 content: 0.052 g (3 oz. Grass-fed); 0.039 (3 oz. conventional); Yes, grass-fed beef will consistently have a statistically significant increase in Omega 3, but this difference is inconsequential compared to a 3 oz. serving of salmon, which has 1.83 g. The daily recommended intake of Omega 3 is 1 g…fish oil, yes please…60 ounces of grass-fed beef, no thank you. Indeed, the ratio of Omega 3 to 6 in grass-finished beef, being lower than conventional beef, is more optimal (about 1:4 vs. 1:10; Schmid et al., 2006; Leheska et al., 2008) in the way of reducing arterial swelling, improving circulation, and reducing triglycerides (Morris et al., 1993; Harris, 1997; I will make a qualifying statement about ratios in the section on Fats). I have seen data showing that some grass-finished beef has as much as 0.10 g Omega 3 (Leheska et al., 2008; French et al., 2000), but this value is not likely to improve because of microbial fatty acid alteration in the rumen (natural biohydrogenation – turning polyunsaturated fats like omega 3's into saturated and trans fats). In fact, beef from feedlot-fed cattle have much greater potential to increase in Omega 3 values because of the higher passage rate which reduces microbial interference with the dietary fats. If feedlot animals are fed Omega 3s with linseed or algal oil, their beef increases in Omega 3 to the same level as grass-finished beef (Razminowicz et al., 2007).
2.      Vitamins A and E from grass-fed beef might be found in quantities 7 times higher than conventional beef, but a serving will only provide up to 2% of the daily value for both vitamins (Daley et al., 2010). Beef in general is not a good source of these vitamins.
3.      Fats: Although grass-finished beef has consistently less fat overall than does conventional beef (about 10% less fat, Leheska et al., 2008), the types of fat grass-finished beef offers concerns me. If you ever eat a burger made of grass-fed beef, you'll notice something strange. The grease that falls from the burger to your plate will in a few minutes harden into a hard wax-like substance, reminiscent of candle drippings. Conventional beef patties drip grease that remains oily and doesn't harden much as it cools. As someone with hypercholesterolemia, I am very sensitive to monounsaturated fat—saturated fat ratios. When I lived in Spain during college, I didn’t watch this and almost went on statin medication as a skinny 21-year-old! Monounsaturated fat (MUFA; think olive, canola, pecan oils) makes my HDL (good) cholesterol rise, while saturated fat (SFA; think hard fats like butter, grizzle) makes my LDL (bad) cholesterol rise. Your HDL/LDL can reflect your MUFA/SFA dietary intake (Adams et al., 2010; Gilmore et al., 2011). Grass-fed beef has less MUFA than SFA (ratio of 0.71 – 0.95), while conventional beef has a more optimal ratio of 1.1 – 1.31. Keep in mind that I may cancel out beef's positive "ratio" effects by over-consuming Omega 6 or SFA, so that my overall diet ratio may be far from optimal. Grain-finishing deposits more MUFA, especially where the beef is marbled, while grass-finishing deposits more SFA and even trans fats (3 g in Choice grass-finished beef vs. 0.14 g in Choice conventional beef per serving) because of ruminal biohydrogenation (Smith et al., 2009; other data c/o Dr. Smith). For lower amounts of trans-vaccenic fats, I recommend buying conventional beef or grass-fed beef that grades USDA Select or lower.
4.      CLA: The alleged benefits of CLA (conjugated linoleic acid, a fatty acid only available in products from the cattle/sheep family) are that it fights cancer, reduces arterial inflammation, and lowers body fat. These have been confirmed in laboratory rodent studies (Schultz et al., 1992; Parodi, 1994; Belury, 1995; Nicolosi and Laitinen, 1996; Pariza et al., 1996) but not in human studies (Brown et al., 2010). Grass-finished beef can offer up to two or three times as much CLA as conventional beef, but both are still a good source at ranges of 0.1 – 0.15 g per serving (Leheska et al., 2008; French et al., 2000).

While scientific credence for health advantages of grass-finished beef wanes, I still buy both types of beef, because both provide 29 different cuts of lean (< 10% fat) meat that don’t even need seasoning like other meats do. As someone prone to anemia and upper respiratory issues that is also at risk for Alzheimer’s disease, it’s good to know that a serving of beef has three times as much iron, six times as much zinc, and seven times the vitamin B12 of chicken. Plus, it’s nice to get as much iron in one serving of beef as there is in three cups of raw spinach, or as much protein as 230 calories of raw tofu, 374 calories in beans, or 670 calories in peanut butter (25g protein from 180 calories of lean beef!). 

Environmental Facts
Any animal management system that does not advance the growth rate of its animals will be inadvertently spending resources for maintenance more so than production, which is wasteful. Slow growing animals will consume more food and water and excrete more solid and gaseous waste per unit of meat or milk they produce. Grass-finished cattle go to market at almost twice the age and at lighter weights than do grain-finished cattle. In light of this…

1.      Land Use: Some neo-agricultural purists advocate finishing all beef produced in this country on pasture. Putting climatic limitations and weather capriciousness aside, let’s say all the acres of grain crops used to finish cattle at feedlots were converted to pasture. It requires 3 times more land to finish cattle on grass than it does to grow crops for finishing cattle in a feedlot (Avery & Avery, 2007). In order to produce the same amount of beef, an additional 60 million acres of non-forested land that receives > 38” annual rainfall would be required to support this goal (Capper et al., 2009). Did anyone find Atlantis yet?
2.      Methane Production: Cattle consuming grass produce as much as 3 times more methane than cattle on a feedlot diet. This has to do with different fermentative pathways that can operate in response to different diets. Since I’m a nutrition nerd, please post a comment and ask about it you’re curious. However, I typically view cattle methane production as a moot point because cattle contribute to only about 15% of world totals (Wahlen et al., 1993…see post “Bitten hands that feed…”).
3.      Sanitation:  Free-ranging cattle like those on a grass-finished system are free to excrete wastes directly into groundwater. Waste deposited by feedlot cattle is contained and treated. Feedlots must follow stringent regulations for water quality control. They must submit a site-specific Pollution Prevention Plan that is engineered to “prevent and limit discharge of pollutants to surface and ground waters” and must include a plan for a catastrophic 100-year, 24-hour rainfall event. For more details, read Avery & Avery, 2007.

I buy beef in general because it keeps open range and wildlife habitat profitable as ranchland instead of as pavement or row crops. Beef cattle management protects 75% of wildlife habitat in the United States from development. 

What do you think?


  1. P.S., here’s how to cook a grass or grain-fed steak to medium in your oven:

    Sear a salted/peppered room temperature steak for 1 minute on each side in a hot iron skillet with olive oil. If grass-fed, place skillet and steak in oven for 25 min. at 275°F. If grain-fed, place in pre-heated oven for 10 min. at 350°F. Sample it to make sure it's cooked to your liking!

  2. Lots of "moo points" being made these days...[anyone see that Friends episode?]

  3. Hi, I'd like to say I appreciate the research and comments you are posting in regards to ag production and agree with the points being made, this needs to get out to all consumers! I currently raise beef that we sell through our local CSA, farmer's market and at our ranch, we have went through all the usda approvals to do so. We developed our herd here on native pasture to finish at approx. 14 months so we do not have the need to use growth hormones, but do grain finish the last 90 days or so. This is just our preference. Unfortunately, being first generation ranchers and still purchasing our ranch we are not privy to a substantial amount of land as others are fortunate to have or I believe I would try just grass finish. Anyhow, when I am selling at markets, the biggest question/concern i get in regards to the grain is if the corn is non-gmo. I do not purchase organic feed so I reply not that I'm aware of. I realy do not see how this affects the beef, do you know of any research or studies on this? Or is the question being posed to me just because of the environmental affects that some are becoming fearful of? I should mention we are in California, so this concern may be distored a bit! Any info you know of I would definitely apreciate. Again, thanks for your insight and keep up the good work putting US ag production in a good, truthful light!

  4. Thanks so much for your comment, you raised some excellent questions that inspired today's post on GMO's, where I described the health and political issues. The environmental concerns have to do with genes that trespass into native or wild plants (like Johnsongrass, for example) but the is why Monsanto would never develop a RoundUp Ready Sorghum. Johnsongrass would be uncontrollable with herbicides! They think of these problems before we do. Thanks for your comment!

  5. The author first admits that grass fed beef yields a healthier product but then tries to discredit the fact by suggesting that it is not healthier enough. This is illogical. Just because grass fed beef does not provide enough Omega 3s to replace Salmon does not make improving omega 3s in beef less important. If feed lots deliver on the potential, so much the better.

    A study from the Nutrition Journal seems to discredit the author's anecdotal comments on fat:

    I do not think we are finding that grass fed (grass finished if you prefer) beef is any less healthy. I think we are discovering that it is not the holy grail but that should not surprise anyone who thinks about it for a minute. With current practices, grass fed beef produces a healthier product. That does not mean conventionally produced beef is unhealthy or that it should be avoided.

    As for the comments on the environmental effects, I question the impartiality of the Hudson Institute article which appears to be the authors primary and only source.

    For all my criticism, I think the author brings out an important point. While it is a good thing to improve the quality and health promoting qualities of our food and to consider all the ramifications of our food production, it is critical to be honest and clear headed in doing so. Always beware of zealots, blinded by their own dogma.

  6. Hi Smittie,
    I appreciate your comments and feedback. I'll try to address everything as succinctly as I can. I'm not sure where I said grass fed beef was a healthier product than grain-finished as you mentioned. If you mean that I quote the difference of Omega-3 content in a serving of beef, but then offer some perspective for that difference, then I see what you're looking at, but I need more help seeing how the rhetoric is illogical. You are correct in pointing out that every little bit helps when it comes to an essential nutrient like Omega 3.
    The article you found is great. The side-by-side comparison of fats in grass-fed and grain-fed beef is a conundrum because select vs. select (same amount of marbling, low) comparisons do indeed appear similar between grass-fed and grain-fed. It's when grass-fed beef is USDA choice (higher marbling)and compared to grain-fed beef that is also USDA choice where the differences start diverging quite dramatically. In general, a USDA select (or lesser grade) serving of beef is the same whether it is from grass-fed or grain fed. It's the USDA choice grass-fed beef I avoid for the sake of my sensitive-to-Saturated fat cholesterol issues.

    Here are a few more environmental impact studies showing that grain-finishing has a reduced footprint: