<qa>  What is the main reason for the detrimental effect of TFA from PHVO?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. 