trans-Vaccenic acid is produced naturally in animals by the partial biohydrogenation of linoleic acid and lpha-linolenic acid. trans-Vaccenic acid does not appear to have the harmful health effects in animals that commercial trans-fats have. On the contrary, it has been found that trans-vaccenic acid is converted to the beneficial cis-9, trans-11 octadecadienoic acid (CLA) in animals via the delta-9-desaturase enzyme, probably in adipose tissues, and this mechanism is undergoing much research in an attempt to increase the amount of CLA in animals and milk.1 trans-Vaccenic acid is the predominant trans monoene in ruminant fats and is formed by incomplete biohydrogenation of dietary fatty acids in the rumen. It has demonstrated insulinotropic effects when incubated with D-glucose in an animal model2 and a study has demonstrated that trans-vaccenic acid can have substantial hypo-triglyceridemic effects.3
