23 November 2001

The Emerald Steak: Nutritional Value of Grassfed Beef

Beef fits well into a balanced diet. Beef protein includes all the essential amino acids for building muscle and performing other functions.1 It also supplies numerous B vitamins and significant amounts of zinc and iron.

Beef’s Nutrient Bundle3
This chart lists the amount of other food you would need to get the same amount of each nutrient found in a 3-ounce serving of beef.

Zinc = 3 4-ounce cans of tuna

Iron = 5 ¼ cups of spinach

Thiamin = 1 ½ chicken breast

Riboflavin = 2 ¼ chicken breasts

B12 = 8 ½ chicken breasts

Source: USDA Nutrient Database for Standard Reference, Release 12

Zinc plays an important role in immune system function and wound healing. Because the majority of beef’s iron content comes from the heme molecule, it is more available to humans than iron from many plant sources.2 Iron occupies a critical part of the hemoglobin molecule, facilitating blood oxygen-carrying ability. Proper nerve function and development depend on the adequacy of both these minerals, particularly during infancy and early childhood (the period of greatest brain development).4

Beef and Cholesterol
People often overlook these nutritional benefits because of the perception that red meat is bad for you. Beef fat contains a relatively high percentage of saturated fat (nearly 50%) due to the high level of saturated fats synthesized by rumen microorganisms. This might suggest a connection between beef and increased blood cholesterol (LDL). However, more and more evidence suggests that stearic acid (a saturated fat constituting 9 to 19% of total beef fat) has no effect on cholesterol. Therefore, the actual affect of beef fat on cholesterol levels is lower than one might expect when considering only its saturated fat content.

Two studies have indicated that lean beef helps lower cholesterol levels.5,6 Davidson et al. found that "National Cholesterol Education Program Step I diets containing primarily lean red meat or lean white meat produced similar reductions in low-density lipoprotein cholesterol (LDL—so-called bad cholesterol) and elevations in high-density lipoprotein cholesterol levels (HDL—good cholesterol), which were maintained throughout 36 weeks of treatment." In a trial comparing a diet containing beef with a diet containing poultry and fish, Flynn et al. found “No statistically significant changes … in [blood fat levels] in men. In women, triglycerides (insoluble fats transported in blood in association with cholesterol) … were significantly higher” after eating poultry and fish versus beef."

Grass Fed Beef
Some unsaturated fatty acids in beef appear to have beneficial effects beyond lowering cholesterol. Conjugated linoleic acid (CLA) appears to provide some significant health benefits. It has stabilized the blood sugar levels in diabetic rats11 and appears to help fight cancer.12,13 Even the small amounts available in a good diet have apparently aided in cancer suppression.14,15 Results from studies done so-far indicate the importance of regularly eating food containing CLA, especially for children whose bodies are still growing.16 Because CLA is a natural product of rumen bacteria, beef and other foods derived from cattle, sheep, or goats contain the highest CLA levels.

The balance between Omega-3 and Omega-6 fatty acids appears particularly important to our nerves. In one study, Omega-3 fatty acids administered in a therapeutic dose “improved the short-term course of illness in patients with [certain types of depression].”17 Higher levels of Omega-3s also appear to increase chances for complete or partial regression of breast cancer after chemotherapy.18 Omega-3 occurs naturally in plants, most concentrated in stems and leaves rather than flowers and seedheads.19

The potential benefit of improving fatty acid content in beef, has motivated research exploring the effect of production practices (breeding, feeding, etc) on beef’s nutritional value.20,21 Because of their higher CLA concentrations, dairy products have come under greater scrutiny recently. However, scientists discovered CLA’s anticarcinogenic activity in fat isolated from ordinary fried hamburger.

Finishing cattle on pastures increases the levels of both CLA and Omega-3s in beef.25,26 ("Finishing" refers to the period of high nutrient intake whereby animals reach an appropriate body condition for harvest.) Several other alternatives have also given positive results, but well-managed pasture remains one of the most straightforward options. One experiment indicated a slight genetic predisposition,23 but the longer grain-feeding period for the “inferior” breed could explain much of the difference.

Scientists do not understand all the mechanisms. But Diez-Gonzalez et al. demonstrated the acidifying effect of high grain rations on cattle digestive systems.28 And this condition could change the bacterial population of a cow’s digestive system enough to change the fatty acids that the bacteria produce.27 This might explain the increased CLA when a cows eats pasture rather than grain. The increased vegetative plant material might also explain the Omega-3 increase.

These differences give grass fed beef fat a slightly yellow or off white appearance. And increased polyunsaturated fatty acids, particularly Omega-3s, may alter the flavor and cooking aroma slightly, resulting in a somewhat gamier but generally not offensive flavor.

1National Cattlemen’s Beef Association, “Beef’s Nutrient Bundle,” Cattle and Beef Handbook, (National Cattlemen’s Beef Association, Englewood, CO, Sixth printing June 1999) p. A-5.
2NCBA, Cattle and Beef, A-4.
3NCBA, “Beef’s Nutrient Bundle,” Cattle and Beef, p. A-3.
4NCBA, Cattle and Beef, A-9.
5M. H. Davidson et al., “Comparison of the effects of lean red meat vs lean white meat on serum lipid levels among free-living persons with hypercholesterolemia: a long-term, randomized clinical trial,” Archives of Internal Medicine, Vol. 28, No. 12, 28 June 1999: 1331-1338.
6 M. A. Flynn et al., “Serum lipids in humans fed diets containing beef or fish and poultry.” American Journal of Clinical Nutrition, Vol. 34, No. 12, December 1981: 2734-2741.
7John R. Romans et al., The Meat We Eat, 14th ed. (Interstate Publishers Inc., Danville, Illinois, 2001) 917.
8National Cattlemen’s Beef Association, “Parity of Beef with other Protein Sources,” Beef Facts: Nutrition, NCBA Fact Sheet 1999: 1.
9M. A. Denke, “Role of Beef and Beef Tallow, an enriched source of stearic acid in a cholesterol-lowering diet,” American Journal of Clinical Nutrition, Vol. 60, 6 Suppl., 1994: 10445-10495.
10National Cattlemen’s Beef Association, “Stearic Acid—A Unique Saturated Fat,” Beef Facts: Nutrition, NCBA Fact Sheet, 1994: 1.
11National Cattlemen’s Beef Association. “Conjugated Linoleic Acid and Dietary Beef—An Update,” Beef Facts: Nutrition, NCBA Fact Sheet, 1999: 3
12V. R. Durgam and G. Fernandes, “The growth inhibitory effect of conjugated linoleic acid on MCF-7 cells is related to estrogen response system,” Cancer Letters, Vol. 116, No. 2, 24 June 1997: 121-130.
13H. B. MacDonald, “Conjugated linoleic acid and disease prevention: a review of current knowledge,” Journal of the American College of Nutrition, Vol. 19, 2 Suppl, April 2000: 111S-118S.
14NCBA, “Conjugated Linoleic Acid,” 3.
15C. Ip, J. A. Scimeca, and H. J. Thompson, “Conjugated linoleic acid: A powerful anticarcinogen from animal fat sources,” Cancer, Vol. 74, 3 Suppl, 1 August 1994: 1050-1054.
16NCBA, “Conjugated Linoleic Acid” 8.
17A. L. Stoll et al. “Omega 3 fatty acids in bipolar disorder: a preliminary double-blind, placebo-controlled trial,” Arch Gen Psychiatry, Vol. 56, No. 5, 1999: 407-412.
18“Natural Omega-3 Complements New Drugs in Cancer Research,” From the Oregon Medical Press, in Stockman GrassFarmer, Vol. 58, No. 10, October 2001: 31.
19Jo Robinson, Why Grassfed is Best, (Vashon, WA, Vashon Island Press, 2000) 14.
20Antti Aro et al., “Inverse Association Between Dietary and Serum Conjugated Linoleic Acid and Risk of Breast Cancer in Postmenopausal Women,” Nutrition and Cancer, Vol. 38, No. 2: 151-157.
21N. D. Scollan et al., “Manipulating the fatty acid composition of muscle and adipose tissue in beef cattle,” The British Journal of Nutrition, Vol. 85, No. 1, January 2001: 115-124.
22NCBA, “Conjugated Linoleic Acid,” 2.
23F. L. Laborde et al., “Breed effects on growth performance, carcass characteristics, fatty acid composition, and palatability attributes in finishing steers,” Journal of Animal Science, Vol. 79, No. 2, February 2001:355-365.
24S. K. Duckett, et al., “Effects of time on feed on beef nutrient composition,” Journal of Animal Science, Vol. 71, No. 8: 2079-2088, in Robinson 14.
25J. D. Wood and M. Enser, “Factors influencing fatty acids in meat and the role of antioxidants in improving meat quality,” British Journal of Nutrition, Vol. 1, 78 Suppl, July 1997: S49-60.
26P. French 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, Vol. 78, No. 11, November 2000: 2849-2855.
27P. J. Van Soest, Nutritional Ecology of the Ruminant, 2nd Ed., (Cornell University, Ithica, NY) in D. E., Bauman et al., “Biosynthesis of Conjugated Linoleic Acid in Ruminants,” Proceedings of the American Society of Animal Science, 1999, (Cornell University, Ithica, NY) 3.
28F. Diez-Gonzalez et al., “Grain Feeding and the Dissemination of Acid-Resistant Escherichia coli from Cattle,” Science, Vol. 281, 1998: 1666.
29J. D. Wood et al., “Manipulating meat quality and composition,” The Proceedings of the Nutrition Society, Vol. 58, No. 2, May 1999: 363-370.
30J. S. Elmore et al., “Effect of the poly unsaturated fatty acid composition of beef muscle on the profile of aroma volatiles,” Journal of Agric. Food Chem., Vol. 47, No. 4, April 1999: 1619-1625.
31I. B. Mandell, J. G. Buchanan-Smith, and C. P. Campbell, “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,” Journal of Animal Science, Vol. 76, No. 10, October 1998: 2619-2630.
32Romans 913.

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