Alpha Linolenic acid: Nutraceutical, pharmacological and toxicological evaluation

Alpha Linolenic acid (ALA), a carboxylic acid with 18 carbons and three cis double bonds, is an essential fatty acid needed for human health and can be acquired via regular dietary intake of foods that contain ALA or dietary supplementation of foods high in ALA, for example flaxseed. ALA has been reported to have cardiovascular protective, anti cancer, neuro protective, anti osteoporotic, anti inflammatory, and antioxidative effects. ALA is the precursor of longer chain omega 3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), but its beneficial effects on risk factors for cardiovascular diseases are still inconclusive. The recommended intake of ALA for cardiovascular health is reported to be 1.1 to 2.2 g per day. Although there are limited toxicological data for ALA, no serious adverse effects have been reported. The evidence on an increased prostate cancer risk in association with dietary ALA is not conclusive.  Based on the limited data currently available, it may be concluded that ALA may be beneficial as a nutraceutical/pharmaceutical candidate and is safe for use as a food ingredient. (Authors abstract)

ALA is the precursor of two important longer chain omega 3 fatty acids, EPA and DHA , both of which have vital roles in brain development, cardiovascular health, inflammatory response, etc. ALA shows protective effects against cardiovascular disease when omega 3 fatty acids are sufficiently consumed via the diet, and its mechanisms are associated with down-regulating proinflammatory and pro atherogenic genes, including adhesion molecules and cytokines, during early atherogenesis or during the later stage of plaque development. In patients with mild hypercholesterolemia, ALA rich oil was able to decrease oxidative stress and CD40 ligand, a protein responsible for various immune and inflammatory responses. ALA can also reduce endoplasmic reticulum (ER) stress-mediated apoptosis of stearic acid lipotoxicity in primary rat hepatocytes and protect renal cells against palmitic acid lipotoxicity through inhibition of ER stress. Oral intake of ALA is the major exposure route to humans and ALA has been generally considered to be a safe compound. In this paper, characteristics of ALA as a food ingredient are evaluated from the view of nutraceutics, pharmacology and toxicology, based on the current information, with the intention of providing up to date. ALA is deemed to be safe as a dietary ingredient because it has not been reported to produce serious health problems; is an essential fatty acid; nutraceutical and pharmacological mechanisms support the safety of dietary exposure to ALA as a food ingredient. ALA is not currently regulated in most countries. However, it should be noted that ALA like other fatty acids can produce lipid peroxidation products under exposure to air or UV radiation, which may produce adverse effects if not controlled appropriately. (Editors comments)