[edit] Nutritional supplement
Food-grade flaxseed oil is cold-pressed, obtained without solvent extraction, and marketed as edible flaxseed oil. Fresh, refrigerated and unprocessed, linseed oil is used as a nutritional supplement. It contains the highest level of omega-3 fatty acids among vegetable oils[3], especially alpha-linolenic acid, which may be beneficial for reducing inflammation leading to atherosclerosis,[4] preventing heart disease and arrhythmia,[5] and is required for normal infant development.[6] However, recent well-controlled placebo studies suggest that regular consumption of flaxseed oil may not reduce the risk of stroke, heart disease, or cancer any greater than placebo.[7] Regular flaxseed oil contains between 52 and 63% alpha linolenic acid (C18:3 n-3). Plant breeders have developed flaxseed with higher alpha linoleic acid content (70%) and very low alpha linolenic acid content (< 3%).[8] The USFDA granted GRAS (Generally Recognized As Safe) status for high alpha linolenic flaxseed oil.[9]
Although flax seeds themselves contain lignans, a class of phytoestrogens considered to have antioxidant and cancer-preventing properties,[10][11][12] the extracted linseed oil does not contain the lignans found in flax seed,[10] and therefore does not have the same antioxidant properties. In fact, flax seed oil is easily oxidized, and rapidly becomes rancid with an unpleasant odor unless refrigerated. Even when kept under cool conditions it has a shelf life of only a few weeks.[13][14] Oil with an unpleasant or rancid odour should be discarded. Rancid oils contribute to the formation of free radicals and may be carcinogenic.[15][16][17] Oxidation of flax seed oil is major commercial concern, and antioxidants may be added to prevent rancidification.[18]
May have adverse effect due to its content of neurotoxic cyanogen glycosides and immuno-suppressive cyclic nonapeptides.[19]
