Hi. Fish oil is the best form for us as humans as it comes in the form of EPA and DHA, which is the form we need. For plant-based omega 3's ground chia is the highest source at a ratio of 6:1 omega 3 to omega 6. Flax is next, at a ratio of 3:2 omega 3 to omega 6. Hemp is a 3:1 ratio omega 6 to omega 3. All plant-based forms need co-factors, which are speciifc vitamins and minerals in order for us to convert them to EPA and DHA, the form we use. Hemp and chia contain more co-factors than flax and they convert more easily but all three should be consumed with a multi-vitamin/mineral supplement to make sure all the co-factors are present. Your choice should be based on the other foods in your diet. If you eat fish than no supplement is needed for 3. If you have plenty of nuts and seeds in your diet, than you are getting plenty of omega 6 , which is important too. In fact, you need more 6 than 3. Hemp is the best ratio if you do not have any food sources of essential fatty acids.
If buying a fish oil, make sure it is pharmaceutical grade as they are screened for mercury and other toxins. However, your best plan is to get a variety from both fish and plant forms in your diet and for therpauetic purposes, a fish oil is best.
Response by Lorene Sauro B.A., R.H.N