Conjugated Linoleic Acids in the Dairy Cow: Biological Activities and Applications

摘要

There has been an increasing recognition over the past several years that dietary lipids can play important roles in metabolism and signaling in addition to their classical role as a source of energy (e.g. Jump and Clarke, 1999; Chong and Marx, 2001).One example of a family of lipids that has been implicated in modulating such divergent processes as cancer development, lipid metabolism, bone mineralization and others are conjugated linoleic acids, or CLA. The interest in CLA really began with an attempt by Pariza and coworkers to identify carcinogenic compounds in cooked beef' (reviewed by Pariza, -1999). Ironically, this project instead identified a compound with very potent anti-cancer properties that was finally identified as cis-9, trans-11 CLA. Parodi (1977) had identified this compound several years prior as a component of cow's milk, and it is now clear that ruminant fat depots are the most abundant natural source of this fatty acid. Subsequent studies performed by Ip and coworkers (1991; 1999) elegantly demonstrated that CLA is a potent anticarcinogen in mouse models of mammary cancer and others have demonstrated these anticarcinogenic properties in many other models (reviewed by Pariza, 1999).