Fats - n6 Polyunsaturated (Linoleic Acid)

Background

Polyunsaturated fatty acids contain two or more double bonds. The most common is linoleic acid (LA, 18:2). It is described as 'n-6' due to the position of the double bonds and occurs in seed oils, eg sunflower, safflower and corn. Other n-6 fatty acids include γ-linolenic (18:3), dihomo-γ-linolenic (20:3), arachidonic acid (20:4) and adrenic acid (22:4). LA is the precursor of arachidonic acid, a substrate for eicosanoid production which is also involved in the regulation of gene expression (Ou et al 2001). LA is also found as a structural component of cell membranes and is important in cell signalling. High intakes of n-6 polyunsaturated fats have been associated with blood lipid profiles associated with a lower risk of coronary heart disease (eg lower total and LDL cholesterol, increased HDL cholesterol and reduced triacylglycerol) (Arntzenius et al 1985, Becker et al 1983, Sonnenberg et al 1996).