Flaxseed is a source of essential fatty acids (omega-3 fatty acids like alpha-linoleic acid and omega-6 fatty acids), which are necessary for health. Alpha-linoleic acid seems to reduce risk of cardiovascular diseases by inhibition of vascular inflammation and endothelial function.(1) Use of flaxseed oil results in reduction of blood lipids (total cholesterol and LDL), and so is effective in protection of the heart via this mechanism as well. Also, this oil increases HDL; however, there is fear that despite simultaneous reduction of LDL, the level of heart protection would be decreased. Fortunately, research has shown that the amount of cholesterol exit from the macrophage cells and its entry to the plasma would not be affected.
Flaxseed and its oil suppress the production of oxygen free radicals by white blood cells. Flaxseed contains 32-45% oil, which consists of 51-55% alpha-linoleic acid (ALA) and 15-18% linoleic acid. Flaxseed is one of the richest sources of a lignan called secoisolariciresinol diglucoside (SDG) which has anti-oxidant activity. Flaxseed reduces the occurrence of atherosclerosis caused by hypercholesterolemia without having an effect on serum lipids. The antiatherogenic effect of flaxseed might be due to suppression of oxygen free radical production by multinuclear white blood cells by alpha-linoleic acid or the anti-oxidant effects of SDG. Also, the antiatherogenic effect of SDG in the arteries is attributed to its effect in reduction of serum lipids. In rat, the n-3 fatty acids present in flaxseed oil enhance the effects of antioxidant catalase and glutathione peroxidase enzymes.
