The role of linoleic acid and its metabolites in the lowering of plasma cholesterol and the prevention of cardiovascular disease.

An increase in linoleic acid intake lowers plasma cholesterol and is one of the safest methods for achieving this end. However, the amounts that must be consumed are large. Linoleic acid is metabolized via several routes and it is probable that a metabolite, rather than linoleic acid itself, is responsible for the cholesterol-lowering effect. If that metabolite could be identified, safe, drug-free, cholesterol-lowering might be achieved with much lower doses. Evidence is reviewed which suggests that a long-chain polyunsaturated fatty acid and/or a prostaglandin metabolite may be responsible for the cholesterol-controlling action of linoleic acid. Such metabolites may be effective also in controlling other risk factors for cardiovascular disease, such as elevated blood pressure and enhanced platelet aggregation. Epidemiological studies suggest that low levels of those metabolites, especially dihomogammalinolenic acid and arachidonic acid, are powerful independent risk factors for development of ischaemic heart disease. Further research in this area is urgently needed now that it is broadly accepted that cholesterol-lowering does indeed reduce the risk of cardiovascular disease.