Summary

Conjugated linoleic acid is a mixture of positional and geometric isomers of linoleic acid with conjugated double bonds located at positions 7,9, 8,10, 9,11, 10,12 or 11,13 on the carbon chain. Substantial amounts of CLA are found in products of ruminant origin due to the presence of anaerobic bacteria in the rumen that are responsible for the synthesis of CLA or precursors. Over the past decade there has been increasing interest in this group of fatty acids, particularly because of the potent antioxidative and anticarcinogenic properties attributed to one or more of these isomers. In addition, under some circumstances, dietary conjugated linoleic acid has been shown to decrease fat accretion in rodents. In this review we have compiled some very recent data on the effects of CLA on lipid metabolism in large domestic animals, specifically pigs and dairy cows. There is growing evidence that at least one isomer of CLA is a potent inhibitor of fat accretion and milk fat secretion. While the broad ranging effects of CLA that are discussed may appear reminiscent of some previous much touted snake oils it is hoped that this review may persuade the reader to rank CLA more as a wonder fat