The essential fatty acids (or EFA's) which you need to get from the food you eat, comprise the omega-3 essential fatty acids. They're typically found in saltwater fish, but also in vegetable foods such as flax seed and walnuts. The other group, the omega-6 essential fatty acids, are found in vegetable oils, e.g. sunflower, wheat germ, soya and thistle oil. All these essential fatty acids are polyunsaturated. For vegans, plant oils are an excellcent alternative to fish oils and other animal based sources of essential fatty acids. Key omega-3 fatty acids include eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA), both found primarily in oily cold-water fish. However, recent advancements in dietary supplements have seen an increase in alternative, non-animal sources of EPA and DHA, such as from seaweed. A third omega-3, called alpha-linolenic acid (ALA), is found primarily in dark green leafy vegetables, flaxseed oils, and certain vegetable oils. Although ALA has different effects on the body than EPA and DHA do, the body has enzymes that can convert ALA to EPA. All three are important to human health (Mann & Skeaff,2007).  

Omega-6 fatty acids are beneficial as well. The most healthful of the omega-6s are those that contain linoleic acid. These convert in the body to gamma linoleic acid (GLA) and ultimately to prostaglandins, molecules that help regulate inflammation and blood pressure as well as heart, gastrointestinal, and kidney functions (Mann & Skeaff,2007). Good dietary sources of omega-6 fatty acids include cereals, eggs, poultry, most vegetable oils, whole-grain breads, baked goods, and margarine. Interestingly, nutritionists are now finding that omega-6s and omega-3s will only maintain their status as "good" fats when you get balanced amounts of both. Unfortunately, most Western diets today are heavy on omega-6s, often at the expense of omega-3s. This means that, for most people, omega-6 supplements are probably not necessary. The best way to ensure adequate intake of essential fatty acids is to eat foods rich in omega-3 and omega-6 fatty acids. Plant oils (flaxseed oil, and evening primrose oil) can also be used to compensate for a diet that is deficient in essential fats. Studies show that omega-3 fatty acids can reduce the risk for heart disease, boost your metabolic rate and help your body burn more fat (Buckley & Howe, 2009). The healing powers of a number of therapeutic oils rich in omega-6s, such as evening primrose oil (EPO), borage oil, black currant seed oil, and flaxseed oil among them, can be attributed to their high concentrations of GLA. GLA-rich supplements such as borage oil and evening primrose oil help calm inflammation (Belch et al, 1988). Essential fatty acids should be included in all diets, including those seeking weight loss and muscle gain.

Plant Oils are commonly presented & sold as Complementary Medicines, Registered Therapeutic Items or Goods and Formulated Supplementary Sports Foods in Australia. Essential fatty acid supplements are not a sole source of nutrition and should be used in conjunction with an appropriate physical training or exercise programme. Not suitable for children or pregnant women. Should only be used under medical or dietetic supervision. Always read label prior to use.

Belch et al (1988), Effects of altering dietary essential fatty acids on requirements for non-steroidal anti-inflammatory drugs in patients with rheumatoid arthritis: A double blind placebo controlled study. Ann Rheum Dis, 47: 96-104
Buckley & Howe (2009), Anti‐obesity effects of long‐chain omega‐3 polyunsaturated fatty acids. Obesity Reviews, 10(6): 648
Mann & Skeaff (2007), Lipids, in Essentials of Human Nutrition. Ed. Mann & Truswell. Oxford University Press