Now sit down, this get's thick. Following is a "simple" explanation from Kate Clancy, a senior scientist in the Union of Concerned Scientists - from a March 2006 publication called "Greener Pastures: How grass-fed beef and milk contribute to healthy eating."
The three omega-3 fatty acids—the so-called beneficial fatty acids—have been shown in many studies to improve health and prevent disease in humans. CLA has attracted attention because it has demonstrated many beneficial effects in animal studies. We have focused on the levels of these fats in milk and meat from pasture-raised cattle because, beyond their intrinsic value, widespread interest in these substances among health-conscious consumers could help shift American agriculture from conventional to pasture-based feeding systems. (pg 1)and
We reviewed all the studies published in English we could find that compare levels of fatty acids in pasture-raised milk and meat with levels in conventionally produced milk and meat, and converted these levels into amounts per serving of milk, steak, and ground beef. The resulting analysis found statistically significant differences in fat content between pasture-raised and conventional products. Specifically:
• Steak and ground beef from grass-fed cattle are almost always lower in total fat than steak and ground beef from conventionally raised cattle.
• Steak from grass-fed cattle tends to have higher levels of the omega-3 fatty acid ALA.
• Steak from grass-fed cattle sometimes has higher levels of the omega-3 fatty acids EPA and DHA.
• Ground beef from grass-fed cattle usually has higher levels of CLA.
• Milk from pasture-raised cattle tends to have higher levels of ALA.
• Milk from pasture-raised cattle has consistently higher levels of CLA.
At this point, the evidence supporting the health benefits of omega-3 fatty acids and CLA is mixed; the data are stronger for some fatty acids than for others. The strongest evidence, encompassing animal studies as well as experimental and observational studies of humans, supports the effects of EPA/DHA on reducing the risk of heart disease. ALA also appears to reduce the risk of fatal and acute heart attacks, but no other beneficial effects have been shown conclusively. Finally, animal research on CLA has shown many positive effects on heart disease, cancer, and the immune system, but these results have yet to be duplicated in human studies. (pg 2)So - to boil that all down:
- Some scientists have done some studies - not all of these on humans - which say that higher CLA's and Omega 3/6 ratio's are better for you.
- Grass-fed beef has higher CLA's and Omega 3/6 ratio's.
- If you believe these studies, then you might get healthier from eating grass fed beef.
I really don't care.
I like the taste of grass fed beef more than corn-fed. And it's cheaper to raise and better for the environment and my farm in particular.
So if you don't believe in CLA's or Omega 3/6 ratio's or the Tooth Fairy or Santa Claus - you can still eat great-tasting beef and quote scientists who say they do.
Either way, you get a great-tasting meal.