Quality Sources of Omega-3
In order to better help you identify foods that feature a high concentration of Omega-3. I have posted the following chart from www.whfoods.com which shows the World's Healthiest Foods that are either an excellent, very good, or good source of omega-3 fats. Next to each food name, you'll find the serving size they used to calculate the food's nutrient composition, the calories contained in the serving, the amount of omega-3 fats contained in one serving size of the food, the percent Daily Value (DV%) that this amount represents, the nutrient density that they calculated for this food and nutrient, and the rating they established in their rating system. For most of their nutrient ratings, they adopted the government standards for food labelling that are found in the U.S. Food and Drug Administration's "Reference Values for Nutrition Labelling."
Impact of Cooking, Storage and Processing
Omega-3 fatty acids are very susceptible to free radical damage. Oxidation of omega-3 fats limits their shelf life and their ability to provide you with the nourishment you need. Damage to the omega-3s in your food can be caused by light, oxygen, or heat. For this reason, foods that are rich in omega-3s should usually be stored in the refrigerator in a sealed container. This rule not only applies to animal foods like fish, dairy, eggs, and meat but also to plant foods like nuts and seeds.
The grinding of nuts and seeds deserves special mention in terms of its impact on omega-3 nourishment. As described earlier, many nuts and seeds contain valuable amounts of omega-3s in the form of ALA. However, in the case of small seeds like flax or chia seeds, it can be very difficult to chew the seeds and grind them sufficiently with your teeth to help increase the availability of their ALA. For this reason, many people choose to grind seeds (for example, in a coffee grinder) prior to eating or incorporating into a recipe. If you decide to grind your omega-3 rich seeds, their shelf life will be reduced and it becomes especially important to store them in a sealed, opaque container in your refrigerator. To give you a more practical idea of shelf life, pre-ground flaxseeds—packaged by the manufacturer in a gas-flushed, light-protective pouch—will typically last for 6-16 weeks before going bad. By comparison, whole flaxseeds will last 6-12 months when stored properly. If you are grinding your own seeds, we recommend a more modest storage time of 1-2 months.
If you are following a fairly strict vegetarian or vegan diet, it may be especially difficult for you to get EPA and DHA you directly from food. (That's because animal foods are typically richer sources of these omega-3s than plant foods.) For this reason, we recommend that you increase your intake of ALA-containing foods to a level that will provide you with approximately 4 grams of ALA per day. Here are some choices that can help you reach that 4 gram level.
Although we have partially addressed the following issue earlier in this article, we would like to emphasise one ongoing controversy that continues to hang over omega-3 research related to risk of dietary deficiency. That controversy involves metabolism of omega-3s. Researchers know that humans need all forms of omega-3s—including the forms ALA, EPA, and DHA. Researchers also know that humans can take ALA and convert it into EPA and DHA under favourable circumstances. But researchers still don't know is exactly how often these favoruable circumstances exist. Because the research jury on omega-3 metabolism is still out, we recommend taking one of two approaches to your omega-3 nourishment. A first approach is to focus on including not only ALA-rich plant foods in your meal plan, but EPA-rich and DHA-rich animal foods as well. A second approach is to focus exclusively on ALA-rich foods in your meal plan, but greatly increase your intake to the 4 gram level described earlier.