Great info on grass fed beef
http://www.thepaleodiet.com/newsletter/ ... e407.shtml
There is little argument that grass fed cattle accumulates more ω-3 fatty acids in their tissues than grain fed cattle (5, 10-28). This nutrient amplification in tissues occurs because the concentration of 18:3n3 (alpha linolenic acid [ALA]) in pasture grass is 10 to 15 times higher than in grain or typical feedlot concentrates (25). In mammals the liver represents the primary tissue which chain elongates and desaturates 18:3n3 into long chain ω-3 fatty acids (20:5n3, 22:5n3 and 22:6n3) which then can be deposited in muscles and other tissues (41).
Not only do feed lot cattle maintain lower ω-3 fatty acids in their tissues than grass fed cattle, but a characteristic increase in the total ω-6 fatty acids occurs (10, 11, 13, 16, 22, 28) as a result of grain feeding (11). Because typical cereals fed to cattle such as maize (ω-3/ ω-6 = 70.7) and sorghum (ω-6/ ω-3 = 16.2) contain very little 18:3n3 and much higher 18:2n6 (42), the cattle’s tissues reflect the fatty acid balance of the grains they consume.
The case for increasing ω-3 fatty acids in the U.S. diet has broad and wide sweeping potential to improve human health. Specifically, ω-3 fatty acids and their balance with ω-6 fatty acids play an important role in the prevention and treatment of coronary heart disease, hypertension, type 2 diabetes, arthritis and other inflammatory diseases, autoimmune diseases, and cancer (43, 44).