Cardiovascular Effects of Trans Fatty Acids

The position of the double bond in the carbon chain of a fatty acid is indicated in several ways. When counted from the carboxyl end (–COOH) of the molecule, the position ( x ) is denoted by the “Δ– x ”-nomenclature, while the “ n – x ” classification is used when counting starts from the methyl end (–CH 3 ). Thus, “ n –3” means that the double bond is located at the third carbon atom from the methyl end. These double bonds can have either the cis or the trans configuration. Cis means that the two carbon atoms adjacent to the double bound point in the same direction, whereas trans means that the two carbon atoms are located at opposite sides of the double bond. As an example, α-linolenic acid (C18:3 n –3), which belongs to the n –3 family, and one of its trans isomers (C18:3 n –3 Δ–9 c ,12 c ,15 tr ) are shown in Fig 11.1. These two molecules are the so-called “geometrical isomers.”