Conjugated linoleic acids in milk fat: Variation and physiological effects

Much attention has been directed toward conjugated linoleic acid (CLA) since the discovery of its anticarcinogenic properties two decades ago. Many other biological activities have been reported over the past few years confirming that individual CLA isomers present in milk fat have a high health promoting potential. Its possible use in functional dairy products explains the increasing interest of the food industry in CLA research. Recent advances in the analytical methodology offer new possibilities to study the individual effects of the various isomers in biological systems. The aim of this review is to summarize the current knowledge in CLA research including the formation of CLA in cows, analysis of CLA isomers, factors influencing the CLA content in milk, processing of CLA-enriched milk and dairy products, as well as aspects concerning nutrition and health.