 As the detrimental effect of TFA from PHVO is unquestioned Mozaffarian et al. 2006, Ascherio et al. 1999, TFA from ruminant origin may have a neutral or positive effect on the cardiovascular system Pfeuffer und Schrezenmeir 2006, Willett et al. 1993. The main reason is attributed to the different concentrations of TFA-isomers in the fat depending on the origin. Partially hydrogenated vegetable oils contains a high amount of elaidic acids trans-9 18:1 isomer and trans-10 18:1 isomers. Ruminant fats contain a high amount of vaccenic acids trans-11 18:1 isomer. The vaccenic acid can be converted to the harmless conjugated linoleic acid CLA in the human and ruminant metabolic system. 