This nutrient is a naturally occurring polyunsaturated fatty acid found in many foods, particularly beef and dairy products. It can also be synthesized from linoleic acid. This nutrient has attracted much interest since the discovery that it has anticarcinogenic and body fat-lowering effects, and may also reduce cholesterol. This nutrient has been acknowledged by the National Academy of Science as being “the only fatty acid shown unequivocally to inhibit carcinogenesis (cancer development) in experimental animals.” What is this nutrient?