The short chain omega-3 fatty acid is known as plant-based omega-3. This omega-3 is mainly found in plants and farm animals. The highest levels are found in certain vegetable oils. Omega-3 in plants is known as plant-based omega-3. The three long chain omega-3 fatty acids are known as marine omega-3, and they are almost exclusively found in fish and other seafood. Cod liver oil and fish oils also have a high content of marine omega-3 fatty acids.
Why is omega-3 important?
Omega-3 fatty acids are necessary for the body, and they are incorporated into the cell membranes, which are important for ensuring that the cells function optimally. Plant-based omega-3 is actually called alpha-linolenic acid (ALA,18:3 n-3), while the marine omega-3 fatty acids comprise eicosapentaenoic acid (EPA 20:5 n-3), docosapentaenoic acid (DPA 22:5 n-3) and docosahexaenoic acid (DHA 22:6 n-3).
EPA and DHA are the two most important, and play the biggest part in preventing cardiovascular disease. ALA is the precursor of all omega-3 fatty acids, and can be converted into EPA and DHA in the body, but this process is so inefficient that eating foods containing EPA and DHA is recommended. The preponderance of documentation indicates that it is marine omega-3 that prevents cardiovascular disease.
The health authorities in Norway have not yet stipulated a recommended intake of marine omega-3, but recommend that total omega-3 (plant-based omega-3 + marine omega-3) should constitute 1 energy percent of a person's diet. The EU's food safety authority, EFSA, recommends a daily intake of 0.25 grams of marine omega-3 for healthy people, in order to prevent cardiovascular disease. This constitutes an energy percentage of around 0.1. An intake of between two and four grams per day is recommended for people who are already in the risk group for cardiovascular disease.
The Norwegian health authorities recommend that we eat two to three fish dinners a week, half of which should be fat fish. Seafood is an important part of a varied diet, and regular seafood intake is documented to prevent cardiovascular disease. Eating one cod dinner (150g) and one salmon dinner (150g) a week will enable you to meet the EFSA's recommended omega-3 intake. A higher intake of fat fish, e.g. herring, is required to meet the vitamin D requirement, however.
Status in the population
By measuring the fatty acid composition of the red blood cells, it is possible to deduce the level of marine omega-3 in the body.
If you eat a varied diet that includes seafood, it is not difficult to get enough marine omega-3. However, certain population groups such as children, young people and pregnant women eat so little seafood that they don't get enough marine omega-3.
Marine omega-3 in fish feed
More use of plant ingredients in farmed salmon feed has led to a 50 percent reduction in marine omega-3 in salmon over the past ten years. Farmed salmon is, nonetheless, a good source of marine omega-3 fatty acids.