Omega-3 Fatty Acids

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Latest Edit: Iva Lloyd, ND 2021-08-24 (EDT)

See Also Food Supplements

Omega-3 fatty acids are found in large amounts in marine life, especially in the form eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These are long chain fatty acids (containing 20 and 22 carbons) that are polyunsaturated meaning that they contain several double bonds within their carbon chains. EPA and DHA are derived from a parent omega-3 molecule known as alpha-linolenic acid (ALA) [1].

Significant amounts of research has gone into the area of omega-3 fatty acids and the benefits they have on human health, especially cardiovascular health. Of particular interest is understanding the importance of an omega-6, omega-3 balanced diet to increase health and well-being. It is suggested that to optimize health, one must increase intake of omega-3s and decrease intake of omega-6s. In a typical North American diet, the intake of omega-6 fatty acids is approximately 10-40 times higher than the intake of omega-3 fatty acids [2]. This is due to the consumption of large amounts of vegetable oils which contain linoleic-acid. Changes in body fat composition won't occur over night, but require several years of proper daily intake to achieve the proper balance in the body [1]

Omega-3s provide their benefit through a variety of mechanisms namely, they improve one's lipid profile, provide anti-inflammatory effects by producing anti-inflammatory prostaglandins, decrease platelet aggregation, and change the composition of cell membranes [1]

Food Sources

The following foods have the highest concentration of omega-3 fatty acids.

  • EPA and DHA Sources: fish, fish oil (cod liver, herring, menhaden, salmon, pilchard, mackerel, anchovy, and sardine), eggs from hens fed DHA, infant formula, some milks are EPA/DHA fortified
Article Why it is best to avoid farmed salmon, Vital Link; 2008 Summer

Fish that are farmed or cultured do not contain nearly the same high levels of EPA and DHA that wild fish do because they are not fed a diet rich in omega-3s.

  • ALA Sources: canola oil, eggs from hens fed flaxseed, hemp seed oil, eichium seed oil, flaxseed, perilla seed, pumpkin seed, purslane, walnuts, wheat germ, black currant oil

Oils derived from soy, safflower, sesame, and sunflower also contain large amounts of omega-6s which can reduce some of the therapeutic effect of their omega-3 content.


The following is a list of the primary uses for omega-3 fatty acids. [1]

Article Specific Applications of Omega 3s for Cardiovascular Disease, NMJ, [1], 2011 November
  • Cardiovascular Disease (CVD): EPA and DHA intake protect against ventricular fibrillation and sudden cardiac death by inhibiting atherosclerotic formation and improving lipid profile (decreasing VLDL and triglycerides). In fact, some researchers have found fish oils to be more effective at reducing ventricular arrhythmias than pharmaceuticals and therefore providing more protection against and better management of cardiovascular disease. These improvements are not seen with the use of vegetable sources of linolenic acid (omega-3) and linoleic acid (omega-6). Fish oil's ability to treat hypertriglyceridemia appears to be beneficial when other lifestyle and pharmaceutical options have not worked. Eating fish regularly may not be enough to exert this effect which is why supplementation of fish oils has gained in popularity.
  • Elevated Serum Lipids: In studies, fish oils have been found to decrease VLDL cholesterol, plasma triglycerides, plasma cholesterol, and LDL cholesterol. There is enough evidence to suggest that daily supplementation is beneficial for patients with high cholesterol and triglycerides. Furthermore, managing blood lipids can decrease risk of coronary heart disease after suffering a myocardial infarction (heart attack).
  • Hypertension: Some studies have found that fish oils reduce blood pressure in those with high cholesterol and hypertension. One hypothesized mechanism is the fish oil consumption aids in the excretion of sodium and fluids via the kidney thus acting somewhat like a diuretic but without increasing excretion of potassium.
  • Angina: Fish oil supplementation can also reduce angina attacks and protect against death in men recovering from heart attack. It has also been found that fish consumption exerts an anti-inflammatory effect that decreases the risk of coronary artery disease.
  • Stroke: A study done in 1995 showed that men have a lower risk of stroke (by 40%) when they consumed fish five or more times a week compared to men who only consumed fish less than once a week. A similar study was done by Harvard Medical School which showed even more impressive results in a study conducted on women. Women who consume fish five or more times a week had a lower risk of stroke by 52% compared to women who consume fish once a week who had a lower risk by 22%. There was no evidence either, that high consumption of fish increased one's risk of hemorrhagic stroke. Fish oils exert this effect by inhibiting platelet aggregation, lowering blood viscosity, suppressing inflammatory mediators, reducing fibrinogen levels, reduces blood pressure, and reducing insulin resistance.
  • Bypass Patients: Fish oil supplementation may help prevent restenosis (re-closing) after angioplasty.
  • Myocardial infarction (Heart Attack): A proper fatty acid profile can reduce the chance of ventricular fibrillation during a heart attack. Omega-3s can also help reduce ventricular arrhythmias which may occur post heart attack. Furthermore, fish and fish oil consumption can reduce risk of mortality after heart attack.
  • Asthma Eating fish more than once a week decreases the risk for asthma.[3], [4]
  • Pregnancy and Lactation: Omega-3 requirements increase during pregnancy, lactation, and infancy. It is even advised to begin supplementation before conception. Omega-3s are of particular importance for the developing brain and nervous system. Fish consumption (once a week during first 16 weeks) has also lead to a lowered risk of giving birth to a low-birth-weight-infant and premature delivery. Mercury content becomes an issue, however; there is no safe amount of mercury that can be consumed during pregnancy as it is a neuro- and feto-toxin. Fish oil supplements are the safest option for this population as mercury levels are undetectable. Furthermore, DHA has been shown to increase breast milk production.
  • Nephrotic Syndrome: Individuals with nephrotic syndrome often have high triglycerides and high cholesterol. Fish oil supplementation can lower triglycerides in this population and has been clinically beneficial. Fish oils have also been shown to slow the progression of IgA nephropathy (normally renal failure develops 5-25 years after diagnosis).
  • Autoimmune Disease: There is some evidence to suggest that fish oils may also be beneficial for conditions such as lupus erythematosus, dermatomyositis, autoimmune nephritis, multiple sclerosis, and inflammatory diseases atopic dermatitis.
  • Rheumatoid Arthritis: One factor which contributes to this disease is the excessive production of pro-inflammatory mediators. More evidence is becoming available to suggest that fish oils are a beneficial treatment for rheumatoid arthritis due to the inhibition of inflammation seen in this condition. Fish oil supplementation can lead to reduced morning stiffness and less joint tenderness. Some patients may even be able to discontinue use of NSAIDs. High doses of fish oils are needed to see these effects.
  • Psoriasis: Fish oils modulate the inflammatory state in psoriasis by replacing pro-inflammatory arachidonic acid with anti-inflammatory EPA in cell membranes and thus reducing the number of inflammatory mediators. In some patients, it may take up to 4 months to see improvement from fish oil supplementation. Fish oils have also proven to be beneficial in combination with other conventional treatments.
  • Cancer: Several animal studies have shown the anticancer effects of fish oils. They appear to exert this effect by altering the metabolism of carcinogens and modulating the synthesis of inflammatory mediators. Epidemiological studies have shown that people in countries who consume fish on a regular basis have a decreased risk of cancer. For example, Japan has the lowest rates of breast cancer compared to any other industrialized country due to high fish intake. This cancer-protective role seems particularly true for colon and breast cancers. The protective effects were especially beneficial in countries which consume high amounts of animal fats; fish oils appeared to counter-act some of the deleterious effects of animal fats. Intervention trials using fish oil supplementation in patients with benign polyps (a risk factor for colon cancer) showed that individuals taking low-dose fish oils had a drop in abnormal cells in the colon lining and this effect was maintained with long-term treatment. A Japanese studies shows that fish consumption, 5 times a week or more, decreased the risk of lung adenocarcinoma when compared to individuals who eat less fish less than once a week. Fish oil is also beneficial in providing nutritional support for cancer patients suffering from cachexia. This nutritional support, along with other nutritional requirements, may increase life expectancy specifically beneficial for those with end-stage metastatic cancer.
  • Migraine Headaches: Some anecdotal evidence also exists that shows the benefit of using fish oils for migraine headaches. Fish oil supplementation has shown a decrease in the frequency and/or intensity of migraines, particularly in males.
  • Diabetes: Some studies suggest that the type of fat that humans ingest is important when it comes to the action of insulin in tissues. Fish oils also decrease VLDL triglycerides and cholesterol, in type II diabetics, and decreases risk of vascular complications in both type I and II diabetics.
  • Raynaud Disease: A decrease in symptoms with fish oil supplementation is observed in patients with idiopathic Raynaud disease but not Raynaud phenomena secondary to progressive systemic sclerosis or connective tissue disease.
  • Malaria: Some unpublished research has suggested that omega-3 fatty acids in fish oils may be beneficial for malaria.
Article Omega-3 oils in psychiatry, IHP, March 2008
Article Omega-3 Fatty Acid and Epilepsy, NMJ, [2], 2012 September
  • Mental Illness [5]: Omega-3 fatty acid deficiencies can cause many central nervous system issues including decrease dopamine, decreased serotonin receptor density, decreased glucose uptake in the brain, decreased integrity of the blood-brain barrier, and decreased membrane fluidity. This deficiency can lead to ADHD, Alzheimer's Disease, schizophrenia, and depression. Omega-3s may be beneficial for these conditions as well as borderline personality disorder, conduct disorder in children, and bipolar disorder. DHA is the main omega-3 in the brain and EPA is important for reducing inflammation; both can play an important part in treating mental illness.

Prescribing Considerations

The recommended dosages have not yet been established. To determine what your specific requirements are talk to your naturopathic doctor or other trained medical professional.

The following are recommended dosages for health maintenance and do not apply to specific disease conditions [2]

  • Child
  • Supplementation in infants who are breastfed is not necessary if maternal dietary intake is adequate. Supplementation in non-breastfed infants is beneficial but dosage is not established.
  • Adolescent
  • Adult:
  • Dietary: No daily requirement for fish oil or EPA and DHA has been established. The adequate intake for ALA is 1.6g for men and 1.1g for women. Adequate intakes do not take into account disease prevention so a daily requirement for disease prevention is likely much higher.
  • Supplemental/Maintenance: 3000-4000mg fish oil/day (equivalent to approximately 2-3 servings of fatty fish/week); 1 Tbsp 1-3 times daily of flaxseed (or 2-4 Tbsp once daily), ground and consumed with water; 1-2 Tbsp of flax oil daily
  • Pregnancy and Lactation:
  • 300mg of DHA daily promotes healthy neural and optical development in the fetus and child. It can also decrease risk of post-partum depression.
  • Fish oil is available in capsule and liquid forms.
  • A typical 1g capsule contains 180mg of EPA and 120mg of DHA (ratio of 3:2 EPA to DHA), although there are forms with higher EPA or DHA.
  • Emulsions of fish oils are now available that can be used as constituents for salad dressings and other foods. Functional foods, including bars are also becoming available. Some chicken farmers also feed their chickens high omega-3 diets making their eggs rich in omega-3 fatty acids.
  • Many infant formulas now contain DHA.
  • It is recommended to find a product which contains an antioxidant in order to protect the oil.
  • Best tolerated with meals; take in divided doses [6].

Deficiency Symptoms

  • dry, scaly skin
  • hair loss
  • immune system insufficiency
  • inflammation
  • poor wound healing
  • impaired vision
  • reduced childhood growth
  • impaired brain and eye development

Assessment Procedure

No clinical standards for laboratory evaluation of omega-3 fatty acid status has been established. [2]


The safety precautions of Omega-3 Fatty Acids include:

  • Few clinically significant adverse effects have been reported. Rare side effects may include GI complaints (nausea, loose stools, diarrhea), dyspepsia, burping, reflux, abdominal bloating, and discomfort, and flatulence. Patients may complain about a fishy after taste with fish oils. The effects can be lessened if taken with meals and if doses are gradually increased. Daily dose of more than 3g may increase risk of bleeding time. Very high doses may increase risk of nose bleeds, hematuria, and hemorrhagic stroke. In the case of nose bleeds and hematuria, these usually occur with concomitant use of fish oils and other anticoagulants.
  • Children: Caution with the use of fish and fish oil is warranted in infants and children due to the issue of toxic substances in the oil. Methylmercury, present in some fish exposed to pollution, may cause neurological and developmental disorders.
  • Issues of Toxicity
  • Fish oils have an excellent safety profile. The main issue of toxicity surrounding omega-3 fish oils is not a nutritional issue but one of contamination. Toxic substances from pollution, namely from methylmercury, pesticides, heavy metals, toxic organochlorines, and polychlorinated biphenyls (PCBs) can be found in seafood, especially large fish. Wild fish tend to be less contaminated. Furthermore, it is the fish meat that tends to accumulate mercury more than the fish oil and therefore fish oil products are relatively clear of mercury contamination; proper techniques are employed to rid the oil of other contaminates. The issue of sustainability is another problem which presents itself when discussing global use of fish and fish oil products [2]
  • Pregnancy and Breastfeeding
  • Caution with the use of fish and fish oil is warranted in this population due to the issue of toxic substances in the oil. Methylmercury, present in some fish exposed to pollution, may cause neurological and developmental disorders.
  • Adverse Effects in Specific Populations
  • hypomania has been reported in those with bipolar disorder or major depression, however, clinical studies show benefit in this population (monitor closely); elevations in blood glucose have been reported with doses of 3g or greater/day which may be of concern in diabetics and those individuals with hypertriglyceridemia but research is not clear on this.
  • Precautions
  • patients being treated for cardiac arrhythmias require close supervision; similar caution ought to be employed for those with diabetes, hypertension, and other cardiovascular disease; individuals with familial combined hyperlipidemia may experience increased risk of spontaneous bleeding; fish oil use may also increase risk of vitamin A, D, and E toxicity as the oil increases the absorption of these fat-soluble vitamins. Particular caution should be made with use of fish liver oil as they are particularly rich in these vitamins.
  • Interactions:[7]
Supportive or Beneficial:
  • Angiotensin-converting Enzyme (ACE) Inhibitors - Consider co-administration of fish oils with ACE inhibitors in IgA nephropathy to reduce renal damage and slow disease progression.
  • Anticonvulsant Medications - Co-administration may enhance therapeutic action through mediation of inflammatory processes. Preliminary findings indicated reduced frequency of seizures with low dose omega-3 oil.
  • Chemotherapy - Fish oils can benefit oncology patients by reversing decreased appetite and weight loss associated with cancer and chemotherapy. Fish oils can alter pro-inflammatory cytokines, mitigate oxidative damage and drug toxicity and protect cardiac function.
  • Cyclosporine - Co-administration may support kidney function and reduce hypertension.
  • Etretinate - Co-administration may enhance therapeutic efficacy of oral etretinate for patients with recalcitrantpsoriasis. Synergy with acitretin (which replaced etretinate in the U.S. and Canada) seems likely.
  • HMG-CoA Reductase Inhibitors (Statins) - Co-administration can provide synergistic effect in mixed dylipidemias particularly with integrative strategy combining healthy diet, regular exercise, and customized nutrient support program. Some adverse effects may include increase LDL and decreased glycemic control. These potential effects appear to be transient or related to patient-specific factors but can be prevented with aerobic exercise and pectin fiber.
  • Selective Serotonin Reuptake Inhibitors (SSRI) Antidepressants - Co-administration may enhance therapeutic activity of drug due to critical role of essential fatty acids for normal serotonin synthesis.
  • Sulfasalazine (and Oral Corticosteroids) - Omega-3s may reduce many symptoms of inflammatory bowel disease. Co-administration may exert additive effects.


  1. 1.0 1.1 1.2 1.3 Pizzorno Joseph E, Murray Michael T (1999) Textbook of Natural Medicine, Elsevier
  2. 2.0 2.1 2.2 2.3 Stargrove Mitchell Bebell, Treasure Jonathan, McKee Dwight L (2008) Herb, Nutrient, and Drug Interactions, Clinical Implications and Therapeutic Strategies. Mosby
  3. Nagakura T, Matsuda S, Shichijyo K, Sugimoto H, Hata K (Nov 2000) Dietary supplementation with fish oil rich in omega-3 polyunsaturated fatty acids in children with bronchial asthma. Eur Respir J;16(5):861-5. PMID: 11153584.
  4. Okamoto M, Mitsunobu F, Ashida K, Mifune T, Hosaki Y, Tsugeno H, Harada S, Tanizaki Y (Feb 2000) Effects of dietary supplementation with n-3 fatty acids compared with n-6 fatty acids on bronchial asthma. Intern Med;39(2):107-11. PMID: 10732825.
  5. Hoffer Abram, Prousky Jonathan Naturopathic Nutrition, A Guide to Nutrient-Rich Food & Nutritional Supplements for Optimum Health, CCNM Press
  6. Hendler Sheldon S., Rorvik David (Editors). (2001) PDR for Nutritional Supplements, Medical Economics Company Inc.
  7. Stargrove Mitchell Bebell, Treasure Jonathan, McKee Dwight L (2008) Herb, Nutrient, and Drug Interactions, Clinical Implications and Therapeutic Strategies. Mosby