Salmon and other types of coldwater fish are recognized as rich sources of two key omega-3 fats, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Both EPA and DHA have numerous health benefits in reducing inflammation, protecting the heart, and maintaining healthy moods.
But beef from grass-fed cattle also contains ample amounts of EPA and DHA. While it does not contain quite as much EPA and DHA (ounce for ounce) as wild salmon, grass-fed beef contains many other nutrients as well – and is much healthier than grain-fed beef.
Until the 1940s, nearly everyone ate beef that came mostly from grass-fed (or range-fed) animals. Grasses are high in alpha-linolenic acid, which ruminants efficiently convert to EPA and DHA. During the 1950s, however, after corn and wheat became heavily subsidized by the government, cattle were increasingly fed grains to promote faster weight gain and more intramuscular fat, known as marbling.
The shift from grass-fed to grain-fed changed the fat profile of meats and, not surprisingly, has had health consequences. One of the changes is that the amount of anti-inflammatory omega-3 fats has decreased, while some saturated fats and pro-inflammatory omega-6 fats have increased.
In a recent comparison of grass-fed and grain-fed beef, Cynthia A. Daley, PhD, and her colleagues at California State University, Chico, reported that beef from grass-fed cattle was almost always nutritionally superior to meat from grain-fed cattle.
In Daley’s analysis of seven studies, grass-fed beef had consistently higher levels of EPA and DHA, gram for gram, compared with grain-fed beef. Conversely, grain-fed beef had low to negligible amounts of EPA and DHA.
Historically, people consumed an omega-6 to omega-3 ratio ranging from 1:1 to 4:1. The typical American diet now provides an 11:1 to a 30:1 ratio of omega-6s to omega-3s, a shift that is related to an increase in inflammatory diseases.
Grass-fed beef is closer to the more traditional and healthier ratio of approximately equal amounts of omega-6 and omega-3 fats. In contrast, the omega-6 to omega-3 ratio in grain-fed beef is 7:1.
Grass-fed beef also contains larger amounts of conjugated linoleic acid (CLA), a type of fat that may have benefits in reducing both weight and cancer risk. When cattle are fed grains, the types of CLA shift to less healthy forms.
Although grass-fed and grain-fed beef contain approximately the same amounts of saturated fat, ounce for ounce, the composition of that fat is significantly different. Grass-fed beef has a higher proportion of stearic acid, which does not affect cholesterol levels. Meanwhile, grain-fed beef is higher in myristic and palmitic acids, two saturated fats that do raise cholesterol levels.
In addition, the fat in grass-fed beef contains more vitamin E, beta-carotene, and glutathione, compared with grain-fed beef.
Reference: Daley CA, Abbott A, Doyle PS, et al. A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. Nutrition Journal, 2010;9:10.