|Linolenic acid is an 18-carbon polyunsaturated fatty acid with three double bonds. The isomer called alpha-linolenic acid (ALA). Another isomer of linolenic acid is gamma-linolenic acid (GLA). Gamma-linolenic acid is comprised of 18 carbon atoms with three
double bonds. It is also known as 18:3n-6: 6,9.12-octadecatrienoic acid: cis-6, cis-9, cis-12-octadecatrienoic acid: and gamolenic acid. A linolenic acid deficiency will result in hair loss, poor wound healing, and scaly dermatitis.
Alpha-linolenic acid (ALA) is used as a source of energy by the body. It also serves as the parent substance to omega-3 fatty acids, compounds that regulate blood pressure, blood clotting, heart rate, blood vessel dilation, the immune response, and breakdown of fats. Additionally, alpha-linolenic acid lowers triglycerides, another blood lipid fraction which when elevated increases coronary heart disease risk. ALA may reduce the risk of heart disease by improving the arteries that carry blood throughout the body and to the brain, and by lowering cholesterol and triglyceride levels. Essential fatty acids are also used to make brain and nervous tissue. ALA may be useful in treating skin cancer, and may be useful in treating persons with anorexia nervosa. Good sources of ALA include flax seeds, flaxseed oil, canola (rapeseed) oil, soybean oil, margarine, if made from canola or soybean oil, pumpkin, and walnuts. Alpha-linolenic acid is converted in the body to EPA (eiocosapentaenoic acid) usually found in marine oil and DHA (docosahexaenoic acid) usually found in marine fish oil.
Gamma-linolenic acid (GLA) is an important conditionally essential fatty acid (EFA). GLA is an omega-6 polyunsaturated fatty acid (PUFA). Linoleic acid (LA), another omega-6 fatty acid, is found in cooking oils and processed foods and converted to GLA in the body. GLA is then broken down to arachidonic acid (AA) and/or another substance called dihomogamma-liolenic acid (DGLA). GLA formation is dependent on the activity of the delta-O-desaturase enzyme, which is hindered by numerous factors, including aging, nutrient deficiency, trans-fatty acids, hydrogenated oils, smoking, and excessive alcohol consumption. GLA, via conversion to PGE1, exhibits anti-inflammatory, antithrombotic, antiproliferative, and lipid-lowering potential. It also enhances smooth muscle relaxation and vasodilation. GLA may be beneficial in dry-eye conditions such as Sjögren's syndrome (a condition with symptoms of dry eyes, dry mouth, and, often, arthritis). GLA is found naturally to varying extents in the fatty acid fraction of some plant seed oils e.g. evening primrose, black currant, borage, and fungal oils. Spirulina (often called blue-green algae) also contains GLA. Dietary GLA supplementation bypasses the rate-limiting step of delta-6-desaturation and is quickly elongated to dihomo-gamma-linolenic acid (DGLA).