Essential fatty acids (EFAs) are fats that are required by the human body. We need to get through our diet or through supplements. The two significant groups of EFAs are Omega-3 and Omega-6. (There are Omega-9 fatty acids, but they are not essential.) Omega-3 fatty acids include alpha-linolenic acid, EPA, and DHA. Omega-6 fatty acids include linoleic acid.