"CLA is a fatty acid found in beef and dairy fats.  Scientific interest in CLA was stimulated in the late 1980s when a University of Wisconsin researcher discovered its cancer-fighting properties in a study of rats fed fried hamburger.  CLA cannot be produced by the human body, but it can be obtained through foods such as whole milk, butter, beef, and lamb."  So check out "Amazing Graze" an article on the USDA's Web site that was published in the Agricultural Research magazine.