Omega-3 fatty acids: From fins and fish oil 
to flax

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Omega-3 fatty acids are primarily found in fatty fish.
Omega-3 fatty acids are primarily found in fatty fish.

Sources of omega-3 fatty acids

Consumption of fatty fish is by far the best proven way to increase levels of omega-3 fatty acids. Wild Alaskan salmon (sockeye) is a particularly good source, as this fish has the optimal lipid profile. Herring, sardines, and black cod are also high in omega-3 fats. Broiling, baking, and grilling are the best preparation methods. Frying healthy fish in unhealthy oils negates some or all of its beneficial effects. 

Supplementation should be suggested for individuals who do not consume fish 2 to 3 times per week; fish oil is the best source of supplementation. Research has shown that there are more consistent benefits derived from consuming whole fish than isolated EPA/DHA. Fish oil comes in many forms; gelatin capsules and liquids are most common. Liquid forms typically have a higher concentration of omega-3 fats and should be considered especially for individuals for whom higher dosages are recommended. For the best absorption, fish oil in its natural or re-esterified triglyceride form should be considered. 

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Differing amounts of EPA and DHA have been used for different medical problems. According to, dosages range from 300 mg to 4,000 mg of EPA and DHA per day. As with most other foods, whether plant or animal, many of the beneficial effects are derived from the synergy of the combinations of nutrients. In attempting to isolate the "active constituents," the supplement may not be as beneficial as the whole item. This may also be true for cold-water fish. Study findings on EPA/DHA are controversial regarding their therapeutic effects3,4; however, the data on human populations that eat whole fish are not. Whole fish contains not only beneficial omega-3 fatty acids, but also omega-7 fatty acids, which play a role in metabolism and decreasing inflammation, as well as omega-9 fatty acids, which have a role in lipid and blood sugar metabolism. Consuming whole fish oil rather than isolated EPA/DHA omega-3 supplements may offer more benefit because it is closer to the composition of fish than isolated components. Whole fish oil supplements that contain omega-7 and omega-9 components may offer additional benefits beyond supplements that only contain omega-3 fatty acids. 

Benefits of omega-3 fatty acids 

Research has shown that a healthy intake of omega-3 fatty acids can be beneficial in triglyceride management, asthma, attention deficit disorder, bipolar disease, and other conditions. Consumption of whole fish has shown the greatest benefit in cardiovascular and cerebrovascular disease. Eating whole fish has also been shown to decrease the symptoms of rheumatoid arthritis early in the disease process. 

Diets high in omega-6 fatty acids are associated with a 2.3-times increased risk of ulcerative colitis. Preliminary data indicate that omega-3 fatty acid supplementation has been associated with decreases in rates of breast cancer. One large study (N = 30,000) showed a 42% decrease in the risk of age-related macular degeneration with one serving of fish per week. The benefit was greatest with canned tuna or dark-meat fish (eg, mackerel, salmon, sardines, bluefish, and swordfish). 

Higher levels of EPA have been shown to be beneficial in mitigating the symptoms of major and moderate depression, as well as bipolar disorder; depression in elderly patients has also been associated with low levels of EPA. Higher levels of omega-3 fatty acids from fish have been shown to be beneficial in age-related cognitive decline and memory enhancement. Acne severity has been shown to decrease with higher levels of omega-3 fatty acids. In prenatal studies, higher DHA levels have been associated with better neurologic development in the fetus. DHA has been found to be concentrated in the nervous system, particularly in photoreceptors and synaptic membranes.5

Choosing a supplement

When choosing a supplement, it is imperative to avoid contaminants, as neurotoxins and carcinogens can accumulate in fish. Consumers should look at labels or manufacturers that meet Good Manufacturing Practice standards. To avoid contaminants, supplements made from small, oily fish that are low on the food chain should be chosen; anchovies and sardines are common. Fish liver oils can contain high levels of vitamin A, in the form of retinol, which can be toxic in high dosages over time; molecularly distilled products generally contain the highest concentrations. Clinicians should research the brands they recommend and have confidence in their manufacturing process and testing procedures for contaminants.

Lynn Green, APNP-BC, MSN, MHC, is a fellow with the University of Arizona Center for Integrative Medicine and a member of Green & Associates, Consultants, LLC.


  1. Egger G, Dixon J. Beyond obesity and lifestyle: A review of 21st century chronic disease determinants [published online April 7, 2014]. Biomed Res Int. doi: 10.1155/2014/731685. 

  2. Simopoulos AP. The importance of the omega-6/omega-3 fatty acid ratio in cardiovascular disease and other chronic diseases. Exp Biol Med (Maywood). 2008;233(6):674-688. 

  3. Rizos EC, Ntzani EE, Bika E, et al. Association between omega-3 fatty acid supplementation and risk of major cardiovascular disease events: a systematic review and meta-analysis. JAMA. 2012;308(10):1024-1033. 

  4. Filion KB, El Khoury F, Bielinski M, et al. Omega-3 fatty acids in high-risk cardiovascular patients: A meta-analysis of randomized controlled trials. BMC Cardiovasc Disord. 2010;10:24. 

  5. Bazan NG, Molina MF, Gordon WC. Docosahexaenoic acid signalolipidomics in nutrition: Significance in aging, neuroinflammation, macular degeneration, Alzheimer's, and other neurodegenerative diseases. Annu Rev Nutr. 2011;31:321-351.

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