They function as essential building blocks in every membrane of every cell in your body, keeping beneficial substances within your cells and harmful ones out. Because our bodies cannot make them, we have to obtain them from vegetable and fish sources, where they are naturally occurring.
Flax seed contains high amounts of both essential fatty acids and is a natural, vegetarian source.
Today's North American diet is sorely lacking in omega-3 EFAs. Our intake of omega-6 EFAs are much higher but mostly from refined and hydrogenated oils, and these have negative effects. Good quality omega-6 is available in fresh vegetables. The best omega-3 vegetable source is flax seeds.