chapter  23
Conjugated Linoleic Acids: Nutrition and Biology
Pages 22

I. Introduction ........................................................................................................................ 579 II. Chemistry............................................................................................................................ 579 III. Analysis of CLA in Food and Biological Samples............................................................ 580 IV. CLA Content in Food Products and Biological Samples .................................................. 581 V. Nutrition and Biology of CLA........................................................................................... 582

A. Cancer ......................................................................................................................... 583 B. Cardiovascular Disease ............................................................................................... 585 C. Body Fat and Lipid Metabolism................................................................................. 586 D. Bone............................................................................................................................ 587

VI. Mechanisms of CLA Action .............................................................................................. 588 A. Antioxidative Action .................................................................................................. 588 B. Biochemical and Physiological Actions ..................................................................... 589 C. Immune Function Modulation .................................................................................... 592

VII. Potential Adverse Effects of CLA...................................................................................... 592 References ..................................................................................................................................... 593

Conjugated linoleic acids (CLAs) are a family of positional and geometric isomers of octadecadienoic acid (18:2). Double bonds in CLA are conjugated and not separated by a methylene group (–CH2-) as in linoleic acid (LA or 18:2n-6), an v-6 essential fatty acid. The CLA isomers are found in many foods [1] but are predominant in products derived from ruminant sources (beef, lamb, and dairy) because of the process of bacterial biohydrogenation of polyunsaturated fatty acids (PUFAs) in the rumen [1-3].