== Ernæring ==
Nogle af de vigtigste omega-3-fedtsyrer, ernæringsmæssigt set, er [[alfalinolensyre]] (ALA), [[icosapentaensyre]] (EPA) og [[docosahexaensyre]] (DHA).<ref name="nih">[https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/ nih.gov: Omega-3 Fatty Acids. Fact Sheet for Health Professionals] Citat: "...The two major classes of polyunsaturated fatty acids (PUFAs) are the omega-3 and omega-6 fatty acids...Several different omega-3s exist, but the majority of scientific research focuses on three: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA)...The human body can only form carbon–carbon double bonds after the 9th carbon from the methyl end of a fatty acid [1]. Therefore, ALA and linoleic acid are considered essential fatty acids, meaning that they must be obtained from the diet [2]. ALA can be converted into EPA and then to DHA, but the conversion (which occurs primarily in the liver) is very limited, with reported rates of less than 15% [3]. Therefore, consuming EPA and DHA directly from foods and/or dietary supplements is the only practical way to increase levels of these fatty acids in the body...ALA is present in plant oils, such as flaxseed, soybean, and canola oils [3]. DHA and EPA are present in fish, fish oils, and krill oils, but they are originally synthesized by microalgae, not by the fish. When fish consume phytoplankton that consumed microalgae, they accumulate the omega-3s in their tissues [3]... Plant oils that contain ALA include flaxseed (linseed), soybean, and canola oils [2,3]. Chia seeds and walnuts also contain ALA...The omega-3 content of fish varies widely. Cold-water fatty fish, such as salmon, mackerel, tuna, herring, and sardines, contain high amounts of LC omega-3s, whereas fish with a lower fat content—such as bass, tilapia and cod—as well as shellfish contain lower levels [3]. The omega-3 content of fish also depends on the composition of the food that the fish consumes [24]. Farmed fish usually have higher levels of EPA and DHA than wild-caught fish, but it depends on the food they are fed [24,25]. An analysis of the fatty acid composition of farm-raised Atlantic salmon from Scotland showed that the EPA and DHA content significantly decreased between 2006 and 2015 due to the replacement of traditional marine ingredients in fish feed with other ingredients [26]. Beef is very low in omega-3s, but beef from grass-fed cows contains somewhat higher levels of omega-3s, mainly as ALA, than that from grain-fed cows [27]...Table 2: Selected Food Sources of ALA, EPA, and DHA [29]...", [https://web.archive.org/web/20200523143158/https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/ backup]</ref>
Kemi Videnskab Ernæring Naturvidenskab