Is it Actually Different?

Column #202

Does the biochemistry of grass-fed beef actually differ from grain-fed beef? Many consumers assume the grass-fed claims are just a bunch of hokum like most marketing health food claims. Of course, most consumers, even those keen on health, don’t seek out the science. They mostly go with the emotional flow which is often motivated by scaremongering and marketing tactics. Even most of the diehard grass-fed fans don’t know the science.

Animal science professionals in academia, the government, and the meat industry have been analyzing the differences for at least two centuries. But up through the ages and even into the 1960s, rather than focus on nutrients the comparative research looked at aroma, flavor, tenderness, color, and intramuscular fat. Of course the research at that time supported the anecdotal evidence. Grain-fed beef was not gamey flavored, was more tender, was juicer with more intramuscular fat, the fat was white, the meat wasn’t dark colored, the cattle finished faster, and consumers preferred it.

But eventually the analysis of beef expanded beyond sensory perceptions. Even though Omega-3 fatty acids were known to be essential for normal growth and health since the 1930s, awareness of their many health benefits increased dramatically from 1980 on. Since it was known that the green leaf, not nuts and seeds, was the primary source for Omega-3, by the mid-1980s some meat scientists started comparing the fatty acid profiles of grass-fed livestock versus grain-fed livestock. By the mid-1990s it was crystal clear that fatty acid profiles in meats differed significantly depending on whether the animals had a grass- or grain-based diet. Year after year since, new research keeps confirming the earlier work.

Naturally, most conventional cattlemen don’t believe a word of it. Many actually believe grass-fed cattlemen are enemies of the “real” cattle business--almost worse than PETA followers! They are that misguided. Not too many years ago I was exchanging emails with the editor of a popular beef industry magazine. He cut the exchange short by telling me in no uncertain terms that I was nuts and he really didn’t want to hear from me. He was beyond hostile.

What convinced me about the nutritional advantages of grass-fed livestock was not just someone telling me it was better. It was research data from papers that compared the chemistry of grass-fed with grain-fed. To augment the few convincing reports I had accumulated in 1999, in 2000 I contacted Tommy L. Wheeler, Ph.D. and asked him for additional reports comparing grass-fed with grain-fed.

I figured he would be a great source since he was a meat research scientist working for the United States Department of Agriculture in its world famous U.S. Meat Animal Research Center in Clay Center, Nebraska. A few years back he was credited with authoring or coauthoring 175 refereed journal publications, 110 abstracts, 76 technical reports, two patents, and two book chapters, and had been the recipient of numerous awards from various scientific organizations. He didn’t let me down. I still have a thick folder containing the reports he sent.

Since those early days the Internet has matured and hundreds of additional reports are now readily available with way less effort. One of them is “A Review of Fatty Acid Profiles and Antioxidant Content in Grass-Fed and Grain-Fed Beef” by Cynthia A. Daley, et al. That 2010 report reviewed seven studies conducted between 2004 and 2009. It was aimed at quantifying some of the stark differences between the two meats.

Because of mounting evidence regarding fat profiles as a cause of disease, rather than focusing on many nutrients this particular report limited its focus to mostly fatty acids. The authors explained that all red meat, regardless of feeding regimens, is nutrient dense and regarded as an important source of essential amino acids, vitamins A, B6, B12, D, E, K, and minerals, including iron, zinc, and selenium. Therefore, they restricted their focus to:
●    Fatty Acid Profiles
●    Conjugated Linoleic Acid (CLA) and Trans-Vaccenic Acid (TVA)
●    β-Carotene/Carotenoids
●    Alpha-Tocopherol
●    Glutathione (GT) & SOD Activity

Fatty Acid Profiles

The first evaluation was for essential fatty acids (EFAs) and that involved the ratio between Omega-6 EFAs and Omega-3 EFAs. Just having one or the other is not nearly as important as the ratio of the two. Ratios close to 1:1 are considered best for optimizing health and wellness and ratios above 4:1 are often associated with chronic diseases. The higher the ratio the worse it gets.

Longer periods of grain-feeding results in higher ratios. Some of the studies in the review had very short 100-day grain-feeding periods. Generally, feedlot stays will be from 150 to 220 days. Some of the studies involved feedlot cattle supplemented with vitamins. Some even supplemented their pastured cattle. So the studies were not perfectly uniform from one study to the next. But just the same, averages of the data showed distinct differences. The EFA ratios for all seven studies averaged 2.2:1 for grass-fed and 7.7:1 for grain-fed. Generally grain-fed livestock exceed 10:1 and can be as high as 20:1.

Conjugated Linoleic Acid (CLA) and Trans-Vaccenic Acid (TVA)

CLA is a naturally occurring fatty acid found in meat and dairy products. It’s a popular dietary supplement that claims it helps people lose fat, maintain weight loss, retain lean muscle mass, and control type 2 diabetes. TVA combined with myeloid cell leukemia-1 inhibitors offers a potential advantage for nasopharyngeal (head and neck) cancer treatment.

The report concluded that on average the “Natural augmentation of CLA c9t11 and TVA within the lipid fraction of beef products can be accomplished through diets rich in grass and lush green forages. While precursors can be found in both grains and lush green forages, grass-fed ruminant species have been shown to produce 2 to 3 times more CLA than ruminants fed in confinement on high grain diets, largely due to a more favorable rumen pH.”

β-Carotene/Carotenoids

Beta-Carotene (a carotenoid) is a precursor of retinol (Vitamin A) a vitamin that is important for normal vision, bone growth, reproduction, cell division, and cell differentiation. Carotenoids are compounds that are synthesized by higher plants as natural plant pigments and are responsible for yellow, orange, and red coloring. Ruminants pass a portion of the ingested carotenoids into their body fat giving it a slightly yellow color. This is perceived as a negative in many countries yet it’s associated with a healthier fatty acid profile and a higher antioxidant content.

The report concluded that “Concentrations were 0.45 microgram/gram and 0.06 microgram/gram for beef from pasture and grain-fed cattle respectively, demonstrating a 7 fold increase in beta-carotene levels for grass-fed beef over the grain-fed contemporaries.”

Alpha-Tocopherol Vitamin E

Vitamin E boosts the immune system, helps prevent blood clots, prevents cell damage caused by free radicals, and is being studied in the prevention and treatment of some types of cancer. It is a type of antioxidant.

The seven reports in the review study showed that concentrations of natural alpha-tocopherol (vitamin E) in grain-fed beef ranged between 0.75 to 2.92 microgram/gram of muscle. Some of the grain-fed beeves were actually supplemented with vitamin E. The pasture-fed beef ranged from 2.1 to 7.73 microgram/gram of tissue depending on the type of forage they were on. The review study concluded that grass finishing increases a-tocopherol levels 3 fold over grain-fed beef.

Glutathione (GT) & Superoxide Dismutase (SOD) Activity

Glutathione (GT) is a tripeptide composed of cysteine, glutamic acid and glycine and it functions as an antioxidant. GT has the capability of quenching free radicals within a cell, thus protecting it from oxidized lipids or proteins and preventing damage to DNA. GT is in virtually all plant and animal tissues. Because GT compounds are elevated in lush green forages, grass-fed beef is particularly high in GT as compared to grain-fed contemporaries.

The review report also noted that grass-fed meat samples were also higher in superoxide dismutase (SOD) and catalase (CAT) activity than beef from grain-fed animals. Superoxide dismutase and catalase are coupled enzymes that work together as powerful antioxidants.

In terms of these antioxidants, the conclusion was that “Grass only diets improve the oxidative enzyme concentration in beef, protecting the muscle lipids against oxidation as well as providing the beef consumer with an additional source of antioxidant compounds.”

Taste, Texture, Color, Cooking

When livestock are fed grain, that alters their biochemistry which dilutes the natural aroma, taste, texture, and color of what had been grass-fed beef. These sensorial perceptions are directly linked to the chemical makeup of the final product. The physical differences extend to even how the meats must be cooked.

The review study hardly scratched the surface of the possible nutrients that could be analyzed. Although it’s unlikely that all nutrients, such as minerals, would be impacted as much as the nutrients covered above. In a 2013 study by S. K. Duckett, et al. some minerals were analyzed and only calcium and possibly iron were measurably lower in feedlot meats. In the years to come I’m certain more complex nutrients will be analyzed and that will be most interesting.

There is no question. Grass-fed beef is not the same as grain-fed beef. They are actually two different foods with some similarities.

Oh, one last point. If feeding grain to livestock can dilute their natural biochemistry, what do you think it does to humans?

To your health.

Ted Slanker

Ted Slanker has been reporting on the fundamentals of nutritional research in publications, television and radio appearances, and at conferences since 1999. He condenses complex studies into the basics required for health and well-being. His eBook, The Real Diet of Man, is available online.

Don’t miss these links for additional reading:

Reports Authored or Coauthored by Tommy Lee Wheeler, Meat Safety & Quality Research, Supervisory Research Food Technologist

U.S. Meat Animal Research Center in Clay Center, Nebraska

A Review of Fatty Acid Profiles and Antioxidant Content in Grass-Fed and Grain-Fed Beef by Cynthia A. Daley, et al.

Impact of Grass/Forage Feeding Versus Grain Finishing on Beef Nutrients and Sensory Quality: The U.S. Experience by Mary E. Van Elswyka and Shalene H. McNeillb

What Are the Benefits of Conjugated Linoleic Acid (CLA)? by Adrienne Stinson

Trans-Vaccenic Acid Inhibits Proliferation and Induces Apoptosis of Human Nasopharyngeal Carcinoma Cells via a Mitochondrial-Mediated Apoptosis Pathway by Jian Song, et al.

Human Health Benefits of Vaccenic Acid by Catherine J. Field, et al.

Superoxide Dismutase: Boosting the Body’s Primary Antioxidant Defense by Dale Kiefer

Effects of Forage Species or Concentrate Finishing on Animal Performance, Carcass and Meat Quality by S. K. Duckett, et al.

History of Meat Science by Robert W. Bray

Effects of Forage vs Grain Feeding on Carcass Characteristics Fatty Acid Composition and Beef Quality in Limousin-Cross Steers When Time on Feed Is Controlled by I. B. Mandell, et al.