Age-related macular degeneration (AMD) is an eye disease that can cause vision loss in older people. Two major National Institutes of Health (NIH)-sponsored studies, called Age-Related Eye Disease Study (AREDS) and Age-Related Eye Disease Study 2 (AREDS2), showed that dietary supplements containing specific combinations of vitamins, antioxidants, and zinc helped slow the progression of AMD in people who were at high risk of developing the advanced stage of this disease. AREDS2, which had more than 4,000 participants and was completed in 2013, also tested EPA and DHA. The results showed that adding these omega-3s to the supplement formulation didn’t provide any additional benefits. Other, smaller studies of omega-3 supplements also haven’t shown them to have a beneficial effect on the progression of AMD. 
In total, 19 articles with 19 data sets revealed the main results of the meta-analysis, namely that there was a significantly better association of treatment with reduced anxiety symptoms in patients receiving omega-3 PUFA treatment than in those not receiving it (k, 19; Hedges g, 0.374; 95% CI, 0.081-0.666; P = .01; Figure 2), with significant heterogeneity (Cochran Q, 178.820; df, 18; I2, 89.934%; P < .001) but no significant publication bias via Egger regression (t, 1.736; df, 17; P = .10) or inspection of the funnel plot (eFigure 2 in the Supplement). According to the trim-and-fill test, there was no need for adjustment for publication bias. The meta-analysis results remained significant after removal of any one of the included studies, which indicated that the significant results are not owing to any single study.
Many studies documenting the benefits of omega-3s have been conducted with supplemental daily dosages between 2 and 5 grams of EPA and DHA, more than you could get in 2 servings of fish a week. But that doesn't mean eating fish is an exercise in futility. Many studies document its benefits. For example, a 2003 National Eye Institute study showed that 60- to 80-year-olds eating fish more than twice a week were half as likely to develop macular degeneration as those who ate no fish at all.

Boucher, O., Burden, M. J., Muckle, G., Saint-Amour, D., Ayotte, P., Dewailly, E. ... Jacobson, J. L.. (2011, May). Neurophysiologic and neurobehavioral evidence of beneficial effects of prenatal omega-3 fatty acid intake on memory function at school age. American Journal of Clinical Nutrition 93(5), 1025-1037. Retrieved from http://ajcn.nutrition.org/content/93/5/1025.full
Fish oil combined with fenofibrate has not been studied extensively in randomized controlled trials. Data to date, however, suggest that the combination is safe and effective.63,64 A recent randomized controlled trial of 100 patients with severe hypertriglyceridemia and HIV on highly active antiretroviral therapy showed that a regimen of fenofibrate and 3 g/d of fish oil for 8 weeks was well tolerated. The median baseline triglyceride level of 650 mg/dL was reduced by 65%.63 Another recent randomized, 2 month, double-blind, placebo-controlled trial, which was set up to assess the safety and efficacy of fenofibrate with 4 g of fish oil, showed that in the 81 patients assigned to combination therapy, triglyceride levels were reduced by 61%. Therapy was well-tolerated without significant adverse reactions at 8 weeks or at the end of a 2-year open label extension.64 The combination of fish oil and niacin requires further study.
Fish oil supplements vary in the amounts and ratios of DHA and EPA they contain. For example, salmon oil naturally contains more DHA than EPA; a supplement derived from algae may only contain DHA. Krill oil contains significant amounts of both EPA and DHA. Read the labels and remember whatever supplement you buy, it must have at least 600 mg of DHA.
Jump up ^ Crowe, Francesca L.; Appleby, Paul N.; Travis, Ruth C.; Barnett, Matt; Brasky, Theodore M.; Bueno-de-Mesquita, H. Bas; Chajes, Veronique; Chavarro, Jorge E.; Chirlaque, Maria-Dolores (2014-09-01). "Circulating fatty acids and prostate cancer risk: individual participant meta-analysis of prospective studies". Journal of the National Cancer Institute. 106 (9): dju240. doi:10.1093/jnci/dju240. ISSN 1460-2105. PMC 4188122. PMID 25210201.
EPA is the precursor to DHA in the body and can be converted to DHA with the enzyme delta-6 desaturase, but this process is inefficient in many people (much like the inefficiency of short-chain omega-3s to long-chain). For those individuals taking pure EPA products as well as those taking our EPA-rich products, we still recommend eating oily fish at least once each week to provide a natural source of DHA. Fish provides a unique nutritional package, supplying the diet with important amino acids (the building blocks of proteins) and antioxidants, including vitamins and minerals needed to process fats, so eating fish will also support the natural enzyme-dependent EPA to DHA conversion.
The number of presenters and the amount of information stuffed into an action-packed few days at times felt overwhelming, even for two dedicated omega-3 enthusiasts like us. But one important message did hit home: The omega-3 index could be a helpful indicator of various health risks, and we should all be paying closer attention to this measurement.
Boucher, O., Burden, M. J., Muckle, G., Saint-Amour, D., Ayotte, P., Dewailly, E. ... Jacobson, J. L.. (2011, May). Neurophysiologic and neurobehavioral evidence of beneficial effects of prenatal omega-3 fatty acid intake on memory function at school age. American Journal of Clinical Nutrition 93(5), 1025-1037. Retrieved from http://ajcn.nutrition.org/content/93/5/1025.full
Fish oil supplements are available as liquids or capsules. Some capsules are enteric-coated to pass through the stomach before dissolving in the small intestine, thus helping prevent indigestion and "fish burps". Poorly manufactured enteric-coated products have the potential to release ingredients too early. ConsumerLab.com, a for-profit supplement testing company, reported that 1 of the 24 enteric-coated fish oil supplements it evaluated released ingredients prematurely.[48]
The human body can make most of the types of fats it needs from other fats or raw materials. That isn’t the case for omega-3 fatty acids (also called omega-3 fats and n-3 fats). These are essential fats—the body can’t make them from scratch but must get them from food. Foods high in Omega-3 include fish, vegetable oils, nuts (especially walnuts), flax seeds, flaxseed oil, and leafy vegetables.
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Fish oil combined with fenofibrate has not been studied extensively in randomized controlled trials. Data to date, however, suggest that the combination is safe and effective.63,64 A recent randomized controlled trial of 100 patients with severe hypertriglyceridemia and HIV on highly active antiretroviral therapy showed that a regimen of fenofibrate and 3 g/d of fish oil for 8 weeks was well tolerated. The median baseline triglyceride level of 650 mg/dL was reduced by 65%.63 Another recent randomized, 2 month, double-blind, placebo-controlled trial, which was set up to assess the safety and efficacy of fenofibrate with 4 g of fish oil, showed that in the 81 patients assigned to combination therapy, triglyceride levels were reduced by 61%. Therapy was well-tolerated without significant adverse reactions at 8 weeks or at the end of a 2-year open label extension.64 The combination of fish oil and niacin requires further study.
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Doses for depression range from less than 1 g/day to 10 g/day, but most studies use doses between 1 and 2 g/day. In my practice, I recommend 1 to 2 g/day of an EPA+DHA combination, with at least 60% EPA, for major depression. I am more cautious in patients with bipolar depression, because the omega-3s may bring on mania, as can most antidepressants. In these individuals, I recommend using omega-3 cautiously, and preferably in combination with a prescription mood stabilizer.

In a U.K. study, children of mothers who ate more than 12 ounces a week actually scored better on tests of verbal I.Q., social behavior, and development and communication than children of mothers who ate none. In the Seychelles Islands, where people average 12 fish meals -- not ounces -- a week, there are no reports of links between mercury exposure and poor outcomes in children. These studies suggest that eating less than 12 ounces of fish each week could do more harm to a child's developing neurological system than mercury poisoning.
People should get most of their nutrients from food, advises the federal government's Dietary Guidelines for Americans. Foods contain vitamins, minerals, dietary fiber, and other substances that benefit health. In some cases, fortified foods and dietary supplements may provide nutrients that otherwise may be consumed in less-than-recommended amounts. For more information about building your own healthy eating pattern, visit ChooseMyPlate.gov. MyPlate offers messages, resources, and tools to help you make the choices that are right for you, based on the Dietary Guidelines for Americans.

In lab experiments, animals given krill showed improved navigation skills. What this means is that they achieved higher levels of cognition and memory required to navigate complex territory.28 In addition, research shows that animals supplemented with krill oil showed significantly fewer signs of depression and resignation. This improvement in mood was equivalent to the effect of the prescription anti-depressant drug imipramine (Tofranil®).29
A, Subgroup meta-analysis of the anxiolytic effect of omega-3 polyunsaturated fatty acids (PUFAs) based on an underlying specific clinical diagnosis or not. The anxiolytic effect of omega-3 PUFAs was not significant in the subgroup of participants without specific clinical conditions (k, 5; Hedges g, –0.008; 95% CI, –0.266 to 0.250; P = .95) but was significant in the subgroup of participants with specific clinical diagnoses (k, 14; Hedges g, 0.512; 95% CI, 0.119-0.906; P = .01). Furthermore, the association of treatment with reduced anxiety symptoms of omega-3 PUFAs were significantly stronger in subgroups with specific clinical diagnoses than in subgroups without specific clinical conditions (P = .03). B, Subgroup meta-analysis of the anxiolytic effect of omega-3 PUFAs based on different mean omega-3 PUFA dosages. The anxiolytic effect of omega-3 PUFAs was not significant in subgroups of mean omega-3 PUFA dosages less than 2000 mg/d (k, 9; Hedges g, 0.457; 95% CI, –0.077 to 0.991; P = .09) but was significant in the subgroup of mean omega-3 PUFA dosage of at least 2000 mg/d (k, 11; Hedges g, 0.213; 95% CI, 0.031-0.395; P = .02).

In comparison, the omega-3s found in krill appear to be more rapidly incorporated into red blood cell phospholipids.7 This is important, because not only do scientists view the uptake of essential fatty acids in red blood cells as a biomarker for uptake into the brain,8 but additional research suggests that when omega-3 fatty acids such as DHA are bound to phospholipids as they are with krill, it increases their uptake to the brain.9 This is further supported by human clinical research, which suggests ingestion of phospholipid-bound EPA and DHA increase cognitive function scores to a greater degree compared with scores obtained when the fatty acids in the ingested oil were provided in the triglycerides storage form.10
Fish oil is oil derived from the tissues of oily fish. Fish oils contain the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), precursors of certain eicosanoids that are known to reduce inflammation in the body,[1][2] and have other health benefits, such as treating hypertriglyceridemia, although claims of preventing heart attacks or strokes have not been supported.[3][4][5][6] Fish oil and omega-3 fatty acids have been studied in a wide variety of other conditions, such as clinical depression,[7][8] anxiety,[9][10][11] cancer, and macular degeneration, yet benefits in these conditions have not been verified.[12]
A scientific review published in 2013 looked at omega-3 polyunsaturated fatty acids and prostate cancer prevention. Researchers concluded that there’s a great deal of evidence suggesting that omega-3s have antiproliferative effects – which means they inhibit cancer cell growth – in cancer cell lines, animal models and humans. In addition, the “direct effects on cancer cells” and indirect anti-inflammatory effects on the immune system fighting the cancer likely contribute to the ability of omega-3 fatty acids to inhibit tumor growth. (14)
Jump up ^ Naliwaiko, K.; Araújo, R.L.F.; Da Fonseca, R.V.; Castilho, J.C.; Andreatini, R.; Bellissimo, M.I.; Oliveira, B.H.; Martins, E.F.; Curi, R.; Fernandes, L.C.; Ferraz, A.C. (2004). "Effects of Fish Oil on the Central Nervous System: A New Potential Antidepressant?". Nutritional Neuroscience. 7 (2): 91–99. doi:10.1080/10284150410001704525. PMID 15279495.
Heart rate variability, a possible surrogate outcome for the risk of sudden death, was assessed in a randomized trial of myocardial infarction (MI) survivors with an ejection fraction of 40%. In the 49 patients that were randomized to either fish oil or olive oil, Holter monitor recordings showed an increase in heart rate variability in the fish oil group.31 In a larger cohort assessed in the Japan EPA Lipid Intervention Study (JELIS),32 however, no difference in heart rate variability could be attributed to fish oil.
The human body can make most of the types of fats it needs from other fats or raw materials. That isn’t the case for omega-3 fatty acids (also called omega-3 fats and n-3 fats). These are essential fats—the body can’t make them from scratch but must get them from food. Foods high in Omega-3 include fish, vegetable oils, nuts (especially walnuts), flax seeds, flaxseed oil, and leafy vegetables.
Most vegan omega-3 supplements are made from seaweed, one of very few plant sources of both EPA and DHA. If you’d rather skip the pills, the real thing provides omega-3s as well as vitamin K, vitamin C, niacin, folate, and choline. Seaweed can be eaten raw (look for it at your local organic or Asian market) or dried — try Annie Chun’s Organic Seaweed Snack, which comes in individual packs and is available in several delicious flavors.
Fish oil is very beneficial for pregnant women because the DHA present in it helps in the development of the eyes and brain of the baby. It also helps to avoid premature births, low birth weight, and miscarriages. Research conducted in Denmark, which involved 8,729 pregnant women, concluded that a diet with low amounts of fish resulted in a higher risk of premature or preterm babies.
Abnormal rapid heart rhythms (ventricular arrhythmias). Population research suggests that eating a lot of fish has no effect on the risk for abnormal rapid heart rhythms. Clinical research is inconsistent. Some research shows that taking fish oil daily does not affect the risk for abnormal heart rhythms. But other research shows that taking fish oil for 11 months delays the development of the condition. However, overall, taking fish oil does not seem to reduce the risk of death in people with abnormal rapid heart rhythms.
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