The controversy over polyunsaturated seed oils is in some respects the mirror image of the fight over saturated fats in meat, milk, and eggs. Omega-3 and omega-6 fatty acids are essential fatty acids. They are "essential" since they must be provided by foods because they cannot be synthesized in the body yet are necessary for health. Both act as structural components in cellular membranes and modulate inflammatory responses.
The three main omega-3 fatty acids are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). The principal sources of omega-3 fatty acids are oily fish, flaxseed oil, and nuts like walnuts. The chief omega-6 fatty acid is linoleic acid. The prime sources of linoleic acid in modern diets are seed oils including soybean, corn, cottonseed, sunflower, canola, safflower, rice bran, and grapeseed oils. The use of these oils has increased in modern diets, and they have been dubbed by some self-proclaimed health and wellness gurus as the "hateful eight."
