A six week, double-blind study on fish oil supplementation for body composition showed that the group taking 4 grams/day of fish oil (contained 1600mg if EPA & 800mg of DHA) experienced a significant increase in lean body mass and significant decrease in fat mass compared to a group that took safflower oil (an omega-6 oil). The fish oil group also saw a tendency for decreases in cortisol, a hormone associated with belly fat gain when elevated.
Not all forms of fish oil may be equally digestible. Of four studies that compare bioavailability of the glyceryl ester form of fish oil vs. the ethyl ester form, two have concluded the natural glyceryl ester form is better, and the other two studies did not find a significant difference. No studies have shown the ethyl ester form to be superior, although it is cheaper to manufacture.[114][115]
Although there was significant heterogeneity among the included studies (Cochran Q, 178.820; df, 18; I2, 89.934%; P < .001), the sensitivity test suggested that the main significant results of the meta-analysis would not change after removal of any of the included studies. However, through direct inspection of the forest plot, we detected the potential influence of some outliers, such as the studies by Sohrabi et al56 and Yehuda et al.61 These 2 studies evaluated anxiety symptoms with a visual analog scale of anxiety and test anxiety severity, which are seldom used in psychiatric research and lack a definite report to prove their equivalent sensitivity and specificity to some other frequently used anxiety rating scales, such as depression, anxiety, and stress scales or the Hamilton anxiety rating scale. Therefore, these studies might have affected the interpretation of the current meta-analysis.

It’s uncertain whether omega-3 fatty acid supplements are helpful for depression. Although some studies have had promising results, a 2015 evaluation of 26 studies that included more than 1,400 people concluded that if there is an effect, it may be too small to be meaningful. Other analyses have suggested that if omega-3s do have an effect, EPA may be more beneficial than DHA and that omega-3s may best be used in addition to antidepressant medication rather than in place of it. 


Dry eye. Higher intake of fish oil from the diet has been linked to a lower risk of dry eye in women. But the effects of fish oil in people with dry eye are inconsistent. Some research shows that fish oil reduces dry eye symptoms such as pain, blurred vision, and sensitivity. But fish oil doesn’t seem to improve other signs and symptoms of dry eye such as tear production and damage to the surface of the eye. Taking fish oil also doesn’t improve signs and symptoms of dry eye when used with other dry eye treatments.

Increased EPA levels in the blood and cell membranes effectively regulates inflammatory pathways and reduces total inflammatory ‘load’, so for any inflammatory conditions or concerns, we recommend a phase of pure EPA supplementation for at least 3-6 months. Pre-loading the body with pure EPA (without the opposing actions of DHA for uptake and utilisation) ensures constant replenishment of EPA ’supplies’ to support its high rate of turnover. Since DHA levels remain fairly stable and much lower daily amounts are required, DHA levels can be supported continually through dietary intake, or increased to 250 mg daily in later stages of treatment through supplementation.


There are numerous omega-3 sources with varying proportions of EPA and DHA, and the balance of EPA and DHA in a supplement influences the actions of these fats in the body. For more information about the different types of omega-3 sources and which are most suited for your individual needs, read our page on the different types of omega-3 supplements
ACS Breast Cancer Screening Guideline CDC Guideline for Prescribing Opioids CDC Guideline for Prevention of Surgical Site Infections Consensus Definitions for Sepsis and Septic Shock Global Burden of Cancer, 1990-2016 Global Burden of Disease in Children, 1990-2013 Global Burden of Hypertension, 1990-2015 Global Firearm Mortality, 1990-2016 Health Care Spending in the US and Other High-Income Countries Income and Life Expectancy in the US JNC 8 Guideline for Management of High Blood Pressure President Obama on US Health Care Reform Screening for Colorectal Cancer Screening for Depression in Adults Screening for Prostate Cancer Statins for Primary Prevention of Cardiovascular Disease The State of US Health, 1990-2016 US Burden of Cardiovascular Disease, 1990-2016 WMA Declaration of Helsinki, 7th Revision
Omega-3s are important components of the membranes that surround each cell in your body. DHA levels are especially high in retina (eye), brain, and sperm cells. Omega-3s also provide calories to give your body energy and have many functions in your heart, blood vessels, lungs, immune system, and endocrine system (the network of hormone-producing glands).
Most people get far too little omega-3s in their diet. In fact, research consistently indicates that the majority of Americans have just slightly more than half the amount of EPA and DHA in their tissues than they need for optimum brain and body health. This is partly due to a high dietary intake of unhealthy fats combined with an inadequate intake of EPA and DHA.

In recent years, many people – particularly those who strictly follow a vegetarian or vegan diet – have believed that they do not have to consume animal products to get omega-3s, as long as they are consuming high amounts of plant-based omega-3s. But, as I mentioned before, most of the health benefits that you can get from omega-3 fats are linked to animal-based EPA and DHA fats – not plant-based ALA. They are simply NOT interchangeable.
Henriksen, C., Haugholt, K., Lindgren, M., Aurvag, A. K., Ronnestad, A., Gronn, M., Solberg, R., Moen, A., Nakstad, B., Berge, R. K., Smith, L., Iversen, P. O., and Drevon, C. A. Improved cognitive development among preterm infants attributable to early supplementation of human milk with docosahexaenoic acid and arachidonic acid. Pediatrics 2008;121(6):1137-1145. View abstract.
Omega-3 polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are essential nutrients that have potential preventive and therapeutic effects on psychiatric disorders, such as anxiety and depression,7-15 as well as comorbid depression and anxiety in physically ill patients,16-19 patients with coronary heart disease,20,21 and pregnant women.22,23 Preclinical data support the effectiveness of omega-3 PUFAs as treatment for anxiety disorders. Song et al24,25 found that an EPA-rich diet could reduce the development of anxiety-like behaviors in rats as well as normalize dopamine levels in the ventral striatum. In addition, Yamada et al26 showed that a high dietary omega-3 to omega-6 PUFA ratio reduced contextual fear behaviors in mice and that these effects were abolished by a cannabinoid CB1 receptor antagonist.
The American Heart Association (AHA) has made recommendations for EPA and DHA due to their cardiovascular benefits: individuals with no history of coronary heart disease or myocardial infarction should consume oily fish two times per week; and "Treatment is reasonable" for those having been diagnosed with coronary heart disease. For the latter the AHA does not recommend a specific amount of EPA + DHA, although it notes that most trials were at or close to 1000 mg/day. The benefit appears to be on the order of a 9% decrease in relative risk.[106] The European Food Safety Authority (EFSA) approved a claim "EPA and DHA contributes to the normal function of the heart" for products that contain at least 250 mg EPA + DHA. The report did not address the issue of people with pre-existing heart disease. The World Health Organization recommends regular fish consumption (1-2 servings per week, equivalent to 200 to 500 mg/day EPA + DHA) as protective against coronary heart disease and ischaemic stroke.

However, in both observational studies and controlled clinical trials, eating fish was shown to foster optimal development of a baby’s brain and nervous system, prompting advice that pregnant women and nursing mothers eat more fish rich in omega-3s while avoiding species that may contain mercury or other contaminants like PCBs sometimes found in freshwater fish.
The biggest cause of omega-3 deficiency is the overconsumption of foods high in omega-6 fatty acids. Omega-6 comes from things like fried foods, fast foods and boxed foods that contain vegetables oils like soybean oil, canola oil, sunflower oil, cottonseed oil and corn oil. When you consume too much omega-6, it can decrease your body’s ability to metabolize healthy omega-3 fatty acids. (36)

Nine studies with 10 data sets used omega-3 PUFA dosages of less than 2000 mg/d.35,47,48,51,53,55,56,60,61 The main results revealed that there was no significant difference in the association of treatment with reduced anxiety symptoms between patients receiving omega-3 PUFA treatment and those not receiving it (k, 9; Hedges g, 0.457; 95% CI, –0.077 to 0.991; P = .09) (Figure 3B). Ten studies with 10 data sets used omega-3 PUFA dosages of at least 2000 mg/d.33,34,36,49,50,52,54,55,57-59 The main results revealed a significantly greater association of treatment with reduced anxiety symptoms in patients receiving omega-3 PUFA treatment than in those not receiving it (k, 11; Hedges g, 0.213; 95% CI, 0.031-0.395; P = .02) (Figure 3B). Furthermore, there was no significantly different estimated effect sizes between these 2 subgroups by the interaction test (P = .40).


Metagenics offers a wide range of educational opportunities including webinars, group meetings, and seminars as part of our commitment to continuing functional medicine education. Our goal is to give our practitioners further insight to help address their patients’ unique health needs for a higher level of personalized, lifetime wellness care. We have been sharing this ever-growing body of nutritional and lifestyle research for over 25 years.
Three omega−3 fatty acids are important in human physiology, α-linolenic acid (18:3, n-3; ALA), eicosapentaenoic acid (20:5, n-3; EPA), and docosahexaenoic acid (22:6, n-3; DHA).[67] These three polyunsaturates have either 3, 5, or 6 double bonds in a carbon chain of 18, 20, or 22 carbon atoms, respectively. As with most naturally-produced fatty acids, all double bonds are in the cis-configuration, in other words, the two hydrogen atoms are on the same side of the double bond; and the double bonds are interrupted by methylene bridges (-CH

Fish oil supplements in our study averaged 473.3mg EPA + 243.1mg DHA in a single serving. These average values were stretched by outliers on both extremes of the spectrum. Nature Made Cod Liver Oil (50mg EPA/serving) and Schiff MegaRed Krill Oil (29mg DHA/serving) recorded category lows for the two omega-3 fatty acids. Ocean Blue Professional Omega-3 (1260mg EPA/serving) and Dr. Tobias Optimum Omega-3 Fish Oil (600mg DHA/serving), on the other hand, recorded category highs for EPA and DHA content.
Increasing ALA intake probably makes little or no difference to all‐cause mortality (RR 1.01, 95% CI 0.84 to 1.20, 19,327 participants; 459 deaths, 5 RCTs),cardiovascular mortality (RR 0.96, 95% CI 0.74 to 1.25, 18,619 participants; 219 cardiovascular deaths, 4 RCTs), and it may make little or no difference to CHD events (RR 1.00, 95% CI 0.80 to 1.22, 19,061 participants, 397 CHD events, 4 RCTs, low‐quality evidence). However, increased ALA may slightly reduce risk of cardiovascular events (from 4.8% to 4.7%, RR 0.95, 95% CI 0.83 to 1.07, 19,327 participants; 884 CVD events, 5 RCTs, low‐quality evidence), and probably reduces risk of CHD mortality (1.1% to 1.0%, RR 0.95, 95% CI 0.72 to 1.26, 18,353 participants; 193 CHD deaths, 3 RCTs), and arrhythmia (3.3% to 2.6%, RR 0.79, 95% CI 0.57 to 1.10, 4,837 participants; 141 events, 1 RCT). Effects on stroke are unclear.

Jump up ^ Kwak SM, Myung SK, Lee YJ, Seo HG (May 2012). "Efficacy of omega-3 fatty acid supplements (eicosapentaenoic acid and docosahexaenoic acid) in the secondary prevention of cardiovascular disease: a meta-analysis of randomized, double-blind, placebo-controlled trials". Archives of Internal Medicine. 172 (9): 686–94. doi:10.1001/archinternmed.2012.262. PMID 22493407.
People used to believe that osteoporosis and osteoarthritis were the result of aging and reduced intake of calcium and milk products. Science has now shown that these bone and joint disorders are, in part, due to inflammation. Because of this, bones and joints are prime targets for the anti-inflammatory properties of omega-3 oils from both fish and krill.
Stiefel, P., Ruiz-Gutierrez, V., Gajon, E., Acosta, D., Garcia-Donas, M. A., Madrazo, J., Villar, J., and Carneado, J. Sodium transport kinetics, cell membrane lipid composition, neural conduction and metabolic control in type 1 diabetic patients. Changes after a low-dose n-3 fatty acid dietary intervention. Ann Nutr Metab 1999;43(2):113-120. View abstract.
If you think you may have a medical emergency, call your healthcare provider or 911 immediately. Any mention of products or services is not meant as a guarantee, endorsement, or recommendation of the products, services, or companies. Reliance on any information provided is solely at your own risk. Please discuss any options with your healthcare provider.

Hamazaki, K., Itomura, M., Huan, M., Nishizawa, H., Sawazaki, S., Tanouchi, M., Watanabe, S., Hamazaki, T., Terasawa, K., and Yazawa, K. Effect of omega-3 fatty acid-containing phospholipids on blood catecholamine concentrations in healthy volunteers: a randomized, placebo-controlled, double-blind trial. Nutrition 2005;21(6):705-710. View abstract.
Thanks to fatdog11 for that informative post about PCB’s in fish-oil supplements. Are these same toxicity levels found in fish themselves, or possibly are these levels so high only in highly concentrated fish-oil products? Also, can fatdog11 please inform us more about algae-derived omega-3. What are the DHA and EPA levels in these capsules? What is the cost, and where can they be purchased?
While fish for dinner is one way to get EPA and DHA, most people don’t eat the suggested two to three servings of oily fish per week to reap the benefits of omega-3s. What’s more, there are extremely few food sources, aside from fish, that naturally provide EPA and DHA. With all the benefits that can come from fish oil, it’s no surprise that these supplements are increasing in popularity.
Basil — a flavorful and easy-to-find herb — is a strong source of omega-3 fatty acids. Since basil is used primarily as a seasoning, however, you likely won’t get a full day’s supply of omega-3 from a standard serving. For best results, use whole basil leaves, and add them toward the end of your meal’s cooking time to preserve the plant’s nutrients. In addition to delivering omega-3s, basil teas like Buddha Tea’s Organic Holy Basil Tea also promote calm and reduce cell inflammation.
Sangiovanni, J. P., Agron, E., Meleth, A. D., Reed, G. F., Sperduto, R. D., Clemons, T. E., and Chew, E. Y. {omega}-3 Long-chain polyunsaturated fatty acid intake and 12-y incidence of neovascular age-related macular degeneration and central geographic atrophy: AREDS report 30, a prospective cohort study from the Age-Related Eye Disease Study. Am J Clin Nutr 2009;90(6):1601-1607. View abstract.
While I think the article is good, it does not tell the reader that most of fish oil capsules sold over the counter are unregulated, and contain widely different ingredients and potency levels. They are mostly a waste of money. If you have health concerns, you need to consult an MD or a Registered Dietitian. Not a naturopath, homeopath, or other pseudoscience practitioner. Eat a diet rich in whole grains, nuts, and some oily fish. I take a multivitamin supplement made by CVS, formulated for my gender and age. Not from the food supplement shelves, which are unregulated, and might contain anything at all, or nothing but vegetable oil or cornstarch.

16. Saito Y, Yokoyama M, Origasa H, Matsuzaki M, Matsuzawa Y, Ishikawa Y, Oikawa S, Sasaki J, Hishida H, Itakura H, et al. Effects of EPA on coronary artery disease in hypercholesterolemic patients with multiple risk factors: sub-analysis of primary prevention cases from the Japan EPA Lipid Intervention Study (JELIS). Atherosclerosis. 2008;200:135–40. [PubMed]
The results of several small studies had suggested that taking omega-3 supplements might help relieve symptoms of dry eye disease. However, a 2018 NIH-sponsored study that tested omega-3 supplements for a full year in a larger group (535 study participants) with moderate-to-severe dry eye disease found that the supplements were no more helpful than a placebo (an inactive substance).
AMA Manual of Style Art and Images in Psychiatry Breast Cancer Screening Guidelines Colorectal Screening Guidelines Declaration of Helsinki Depression Screening Guidelines Evidence-Based Medicine: An Oral History Fishbein Fellowship Genomics and Precision Health Health Disparities Hypertension Guidelines JAMA Network Audio JAMA Network Conferences Med Men Medical Education Opioid Management Guidelines Peer Review Congress Research Ethics Sepsis and Septic Shock Statins and Dyslipidemia Topics and Collections

Another small study had all volunteers consume the same exact control diet and substituted fish oil for visible fats (things like butter and cream). The volunteers consumed six grams of fish oil each day for three weeks. They found that body fat mass decreased with the intake of fish oil. The researchers conclude that dietary fish oil reduces body fat and stimulates the use of fatty acids for the production of energy in healthy adults. (33a)

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Some studies suggest that people who get higher amounts of omega-3s from foods and dietary supplements may have a lower risk of breast cancer and perhaps colorectal cancer. More research is needed to confirm this possible link. Whether omega-3s affect the risk of other cancers is not clear. Clinical trials to examine this possibility are in progress.
Soy can get a bad rap — and may indeed cause problems for people with certain food sensitivities — but this delicious bean is one of the most powerful (and versatile) ways to add omega-3 to your diet. Whole soybeans (known as edamame) are a favorite protein-packed snack for vegetarians; more processed forms (including tofu, soy milk, and soybean-based cooking oil) make soy infinitely more accessible. For some ideas, check out the 1998 classic, The Whole Soy Cookbook, which outlines how to cook with soy-based products ranging from miso to tempeh and beyond.
During pregnancy and breastfeeding, eating 8 to 12 ounces per week of fish and other seafood may improve your baby’s health. However, it is important to choose fish that are higher in EPA and DHA and lower in mercury. Examples are salmon, herring, sardines, and trout. It is not clear whether taking dietary supplements containing EPA and DHA during pregnancy or breastfeeding affects a baby’s health or development. However, some studies show that taking these supplements may slightly increase a baby’s weight at birth and the length of time the baby is in the womb, both of which may be beneficial. Breast milk contains DHA. Most commercial infant formulas also contain DHA.

The effect of fish oil on incident atrial fibrillation has not been studied in large randomized trials, and observational population-based trials show mixed results. The Danish Diet, Cancer and Health Study, and the Rotterdam Study followed 47,000 and 5100 middle-aged adults, respectively.45,46 Neither study found that the consumption of fish oil affected the incidence of atrial fibrillation. Similar findings were seen in the Women’s Health Initiative where there was no association between fish and omega-3 FA intake regarding incident atrial fibrillation.47 However, in a 12-year prospective, observational study of 4815 adults over the age of 65, daily fish consumption was associated with a 31% risk reduction in incident atrial fibrillation.48
Bo and I worked with Dr. Harris many years ago to measure the impact of eating one Omega Cookie® daily on the study participants’ omega-3 index levels, and we recently ran into him at ISFFAL. At the conference, we remeasured our omega-3 index and omega-6/omega-3 ratios, and a few weeks later, we got our results in the mail. For the two of us, it was exciting to get another concrete measure of how our daily omega-3 consumption impacted our scores. For the record, we take one vial of Omega Restore™ per night and frequently sneak an Omega Heaven® or Omega Cookie during the day.
A number of trials have found that omega-3 PUFAs might reduce anxiety under serious stressful situations. Case-controlled studies have shown low peripheral omega-3 PUFA levels in patients with anxiety disorders.27-31 A cohort study found that high serum EPA levels were associated with protection against posttraumatic stress disorder.32 In studies of therapeutic interventions, while a randomized clinical trial of adjunctive EPA treatment in patients with obsessive-compulsive disorder revealed that EPA augmentation had no beneficial effect on symptoms of anxiety, depression, or obsessive-compulsiveness,33 a randomized clinical trial involving participants with substance abuse showed that EPA and DHA administration was accompanied by significant decreases in anger and anxiety scores compared with placebo.34 In addition, a randomized clinical trial found that omega-3 PUFAs had additional effects on decreasing depressive and anxiety symptoms in patients with acute myocardial infarction,35 and a randomized clinical trial demonstrated that omega-3 PUFAs could reduce inflammation and anxiety among healthy young adults facing a stressful major examination.36 Despite the largely positive findings of these trials, the clinical application of the findings is unfortunately limited by their small sample sizes.
Ample evidence from animal studies supports regular supplementation with omega-3 oils as a means of lowering long-term cardiovascular risk. This may be due to omega-3 fatty acids’ effects on reducing inflammation, lowering triglycerides, reducing blood pressure, improving endothelial function, inducing new blood vessel formation after heart attack or stroke, and favorable modification of obesity-related inflammatory molecules.35-39
Although results from studies regarding the disease processes of AD seem to be promising, there are conflicting data regarding the use of omega-3 fatty acids in terms of cognitive function. Neuropsychiatric symptoms accompany AD from early stages and tend to increase with the progression of the disease (55). An analysis of 174 patients randomized to a placebo group or to a group with mild to moderate AD (MMSE score ≥15) treated with daily DHA (1.7 g) and EPA (0.6 g) found that at 6 mo, the decline in cognitive function did not differ between the groups. Yet, in a subgroup with very mild cognitive dysfunction (n = 32, MMSE score >27), they observed a significant reduction in the MMSE decline rate in the DHA+EPA-supplemented group compared with the placebo group (47). Another study that looked at DHA supplementation in individuals with mild to moderate AD used the Alzheimer's Disease Assessment Scale–Cognitive subscale, which evaluates cognitive function on a 70-point scale in terms of memory, attention, language, orientation, and praxis. This study found that DHA supplementation had no beneficial effect on cognition during the 18-mo trial period for the DHA group vs. placebo (56).
DHA is vital for early brain development and maintenance, while EPA seems to be closely related to behavior and mood. Together, both molecules provide critical neuroprotective benefits.11 These neuroprotective effects are important for the prevention of age-related brain shrinkage (cortical atrophy). Aging adults with brain shrinkage often experience memory loss, cognitive decline, and an increase in depression.12-14
It is well known that fish oil has the ability to improve vision. It also helps in avoiding age-related macular degeneration. The National Eye Institute at the National Institute of Health in the United States plans to conduct a nationwide study to evaluate the effect of fish oil in treating macular degeneration. This study will provide strong scientific evidence regarding the benefits of fish oil for eye care, thereby allowing government agencies and physicians to strongly recommend fish oil for macular degeneration.
The Federal Government’s Dietary Guidelines for Americans 2015–2020 recommends that adults eat 8 or more ounces of a variety of seafood (fish or shellfish) per week for the total package of nutrients seafood provides, and that some seafood choices with higher amounts of EPA and DHA be included. Smaller amounts of seafood are recommended for young children.
One meta-analysis concluded that omega−3 fatty acid supplementation demonstrated a modest effect for improving ADHD symptoms.[39] A Cochrane review of PUFA (not necessarily omega−3) supplementation found "there is little evidence that PUFA supplementation provides any benefit for the symptoms of ADHD in children and adolescents",[40] while a different review found "insufficient evidence to draw any conclusion about the use of PUFAs for children with specific learning disorders".[41] Another review concluded that the evidence is inconclusive for the use of omega−3 fatty acids in behavior and non-neurodegenerative neuropsychiatric disorders such as ADHD and depression.[42]
So for those people who will not eat liver, cod liver oil on a daily basis can be a very good way of getting that. And you do benefit from the omega-3 fatty acids, and with the cod liver oil, it may even be unimportant to eat fish if you’re getting the cod liver oil, although it’s still better to focus on the fish, the egg yolks, and just add some of the cod liver oil.
For slowing weight loss in patients with cancer: 30 mL of a specific fish oil product (ACO Omega-3, Pharmacia, Stockholm, Sweden) providing 4.9 grams of EPA and 3.2 grams of DHA daily for 4 weeks has been used. 7.5 grams of fish oil daily providing EPA 4.7 grams and DHA 2.8 grams has been used for about 6 weeks. In addition, two cans of a fish oil nutritional supplement containing 1.09 grams of EPA and 0.96 grams of DHA per can have been used daily for up to 7 weeks.
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