Metabolic aspects of trans fatty acids.

The consumption of trans isomers of unsaturated fatty acids has been associated withuntoward metabolic effects. Several clinical investigations demonstrated that trans fatty acids increase plasma LDL-cholesterol and lipoprotein (a) and reduce HDL-cholesterol concentrations. These alterations of plasma lipid profiles indicate an atherogenic effect of trans fatty acids. Both in preterm infants and in healthy children aged 1-15 years, we found blood plasma arachidonic acid (C20:4omega-6) levels and the product/substrate ratios of arachidonic acid synthesis (C20:4omega-6/C18:2omega-6) inversely correlated to the level of the principal trans fatty acid, trans octadecaenoic acid (C18:1omega-9/7, trans), which is compatible with a dose-dependent inhibition of arachidonic acid synthesis by trans fatty acids. Moreover, in premature infants trans fatty acids in blood plasma correlated inversely with birth weight in an observational study, indicating that trans fatty acids may impair early human growth. It appears desirable to limit the dietary intake of trans fatty acids. The major dietary sources of trans fatty acids are partially hydrogenated vegetable and fish oils. Refinement of the industrial technology of partial hydrogenation and appropriate food labelling may lead to a considerably decrease of human exposure to trans fatty acids.