Conjugated Linoleic Acid

Conjugated linoleic acid, better known as CLA, is a fatty acid derived from the required nutrient, linoleic acid. The major structural difference between linoleic acid (an 18 carbon, polyunsaturated fatty acid) and CLA, is that linoleic acid has double bonds at carbons 9 and 12 in a cis configuration (methylene interrupted), while CLA has numerous isomers without methylene interrupted conjugated dienes. The two predominant isomers contained in biologically active preparations contain approximately equal proportions of 9 cis, 11 trans and 10 trans, 12 cis. It is essential that the reader not confuse these non-hydroxylated conjugates with hydroxylated dienes found in the literature. The relevant biological activity of each of these CLA isomers will be reported within the next year. The existence, both naturally and synthetically, of these fatty acids has been known for over 40 years. Early work with these conjugated dienes involved studies in tracing fatty acid metabolism, since they possess a unique ultraviolet absorption pattern relative to fatty acids without conjugated double bonds. However, the research involving these fatty acids failed to reveal the biological activity that is known today (www.poultry.wisc.edu/cla). The reisolation as a naturally occurring bioactive fatty acid by the laboratory of Dr. Michael Pariza (University of Wisconsin) opened the door to a wide array of discoveries of great potential economical value to the poultry and livestock industries.