Contribution of trans fatty acids from vegetable oils and margarines to the Belgian diet.

Nineteen commercial samples of vegetable oils and margarines marketed in Belgium (nine margarines, nineteen vegetable oils), Hungary (seven margarines) and Great Britain (three margarines) were analyzed by gas-liquid chromatography for their trans fatty acid (TFA) content. For the vegetable oil samples under study, the TFA content ranged from 0.0-4.6% (mean : 1.1%, S.D. : 1.1%). Trans isomers in these samples were almost exclusively C18:2 and C18:3 isomers formed during high temperature refining. Trans isomers of the margarines were mainly C18:1 isomers formed during hydrogenation. For the Belgian and Hungarian samples mean trans values of 6.36% (S.D.=6.20%) and 14.06% (S.D.=7.59%), respectively expressed on fat basis were established. From these figures, the average daily intake of TFA from margarines and vegetable oils by the Belgian population was calculated at 1.1 and 0.1g/person/day, respectively. When so-called zero-trans margarines (+/- 0.5% TFA) are consumed, the trans intake can be reduced to about 0.1g/person/day. Further studies leading to figures about the contribution of TFA from 'invisible fat' food products will be conducted in the near future.