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GLA (gamma-linolenic acid)

Unsaturated fatty acids such as linoleic acid (LA) and alpha-linolenic acid (ALA) are essential dietary constituents. Linoleic acid is an essential nutrient which, like a vitamin, cannot be made within the body and so must be taken in the diet. However, in order to be fully useful to the body, LA must be metabolised, first to GLA and then to further metabolites. Linoleic acid can be converted by mammals into gamma.-linolenic acid (GLA) which can in turn be converted to arachidonic acid (20:4), a critically important fatty acid since it is an essential precursor of most prostaglandins. LA has some functions which it can perform itself, particularly in the skin and other membranes and in relation to cholesterol transport, but many of its effects require conversion to GLA and beyond. The GLA and the further metabolites each appear to have particular roles in the body and so this first metabolic step is of particular significance. Gamma-linoleic acid is used to facilitate weight loss by causing thermogenesis. In addition, gamma-linoleic acid appears to increase the level of brown fat Na/K ATPase activity. Brown fat readily burns fat stores for energy and the specific enzyme Na/K ATPase controls the rate of metabolism. Essential fatty acid deficiency has been suggested as being involved in eczema, and studies have shown beneficial effects on eczema from treatment with GLA. GLA has also been shown to reduce increases in blood pressure associated with stress, and to improve performance on arithmetic tests. GLA and DGLA have been shown to inhibit platelet aggregation, cause vasodilation, lower cholesterol levels and inhibit proliferation of vessel wall smooth muscle and fibrous tissue. GLA is therefore used for the human and veterinary treatment of inflammatory and immune diseases, in cardiovascular disorders, in particular high blood pressure, diabetes and certain forms of cancer. The use of GLA is likewise known for the prophylaxis and treatment of chronic, degenerative diseases, in particular rheumatoid arthritis. Gamma-linoleic acid is also known to have some important anti-inflammatory properties, is used to combat high blood pressure, lowers blood viscosity and reduces LDL cholesterol, and is known to improve immune response. Useful sources of GLA are relatively few. The seed oil of the evening primrose (EPO) which contains only 8 to 10% of its fatty acids as GLA has been widely used commercially as a component of foods, as a nutritional supplement, as an ingredient of cosmetic, skin care and hair care products, and as a pharmaceutical.

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