Metabolism of trans and conjugated fatty acids

Trans fatty acids (FA) enter all the metabolic pathways of bioconversion, oxidation and lipid storage and are incorporated into all tissues. They also interfere with the polyunsaturated FA metabolic pathways. Among trans FA, major attention is paid to elaidic and vaccenic acids. The latter is bioconverted into rumenic acid, a conjugated linoleic acid (CLA) isomer, through the Δ9 desaturase pathway. Considering CLA isomers, they are also bioconverted by desaturases and the elongation pathway, but the significance of this conversion is not fully understood. This review considers these different aspects, with particular attention to human data.