Omega 3 is a type of fat. Small amounts of omega 3 fats are essential for good health, and they can be found in the food that we eat. The main types of omega 3 fatty acids are; alpha­linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).  ALA is normally found in fats from plant foods, such as nuts and seeds (walnuts and rapeseed are rich sources). EPA and DHA, collectively called long chain omega 3 fats, are naturally found in fatty fish, such as salmon and fish oils including cod liver oil.
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The National High Blood Pressure Education Program in the United States has cautioned against inaccurate publicity of fish oil as an effective means of lowering high blood pressure in patients suffering from hypertension. According to its report, fish oil supplements lower blood pressure in a very small way in hypertensive patients. Research conducted at the Channing Laboratory in Boston has revealed that moderate doses of fish oil supplements have little effect on the condition of high blood pressure in normotensive people.
^ Jump up to: a b Jensen, Craig L.; Voigt, Robert G.; Llorente, Antolin M.; Peters, Sarika U.; Prager, Thomas C.; Zou, Yali L.; Rozelle, Judith C.; Turcich, Marie R.; Fraley, J. Kennard; Anderson, Robert E.; Heird, William C. (2010). "Effects of Early Maternal Docosahexaenoic Acid Intake on Neuropsychological Status and Visual Acuity at Five Years of Age of Breast-Fed Term Infants". The Journal of Pediatrics. 157 (6): 900–05. doi:10.1016/j.jpeds.2010.06.006. PMID 20655543.
The evidence that fish oil consumption should be used for primary prevention of CAD is based on observational studies. The only randomized trial for primary prevention, the JELIS trial, showed a moderate relative risk reduction and was conducted in a very specific group. Nevertheless, to date, there has been no strong signal suggesting any serious adverse effects of having high DHA and EPA oils in the diet. We agree with the national guidelines that one should consume moderate amounts of fish oil— either in supplement or through the dietary intake of fatty fish with low mercury levels.
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.
Here is a brief on omega-3 fatty acids: There are three types of omega-3 fatty acids, namely alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). All three are important for the body. Vegetable sources, including flaxseed oil, soybean oil, hemp oil, canola oil, walnut oil, rapeseed, perilla, chia, and tofu are rich in ALA. The human body has the ability to convert ALA to DHA and EPA, though there are certain limitations to this conversion.
Several studies suggest that people suffering symptoms of depression and/or anxiety see improvement after adding an omega-3 supplement to their routine, even in double-blinded, randomized, controlled trials. (29, 30, 31, 32, 33) At least one study comparing a common depression medication found omega-3 supplements to be just as effective in combating depression symptoms. (34)
Another study conducted by researchers at Rhode Island Hospital examined the relationship between fish oil supplementation and indicators of cognitive decline. The subjects of the study were older adults: 229 cognitively normal individuals, 397 patients with mild cognitive impairment and 193 patients with Alzheimer’s disease. They were assessed with neuropsychological tests and brain magnetic resonance imaging every six months while taking fish oil supplements. The study found that the adults taking fish oil (who had not yet developed Alzheimer’s and did not have genetic risk factor for developing Alzheimer’s known as APOE ε4) experienced significantly less cognitive decline and brain shrinkage than adults not taking fish oil. (9)
What about blood clotting? Circulating cells called platelets are critical in causing your blood to clot. When platelets are activated, they aggregate and cause clots. If these clots occur in particularly sensitive regions of your body, they can lead to a heart attack or stroke. EPA reduces platelet activation, an early step in platelet aggregation to help to reduce clotting. One study found that EPA was superior to DHA in decreasing platelet activation, a precursor to blood clotting.1

Those foods provide enormous amounts of other nutrients that are good for you. nSo it is way better to eat those foods than to take fish oil. With that said, some people find it very difficult to get vitamin A or vitamin D, and particularly for vitamin A, cod liver oil may be a very important source of that vitamin. Cod liver oil is a form of fish oil that happens to be high in the fat-soluble vitamins. Vitamin A is best found in liver. It’s better in my opinion to eat liver once a week, but there are a lot of people out there who are not going to eat liver once a week. So if you are using cod liver oil to get the vitamins that you can’t get from food—and I should point out that vitamin A can also be derived from plant foods, but many people genetically or for other reasons don’t derive it very well from plant foods.
Although GOED has used diligent care to ensure that the information provided on this website is accurate and up to date, we make no representation or warranty of the accuracy, reliability or completeness of this information. The website is intended to educate and inform readers about omega-3 fatty acids and is not meant to constitute or provide medical advice, diagnosis or treatment and is distributed without warranty of any kind, either expressly or implied. In no event shall GOED be liable for any damages arising from the reader’s reliance upon, or use of, these materials. The reader shall be solely responsible for any interpretation or use of material contained herein. The content of this document is subject to change without further notice.
^ Jump up to: a b Casula M, Soranna D, Catapano AL, Corrao G (August 2013). "Long-term effect of high dose omega-3 fatty acid supplementation for secondary prevention of cardiovascular outcomes: A meta-analysis of randomized, placebo controlled trials [corrected]". Atherosclerosis. Supplements. 14 (2): 243–51. doi:10.1016/S1567-5688(13)70005-9. PMID 23958480.
It is also believed that women who do not have a sufficient intake of EPA and DHA in their diet suffer from depression after childbirth, as there is a transfer of some amount of brain mass from the mother to the child in the last stages of pregnancy. Thus, it is very beneficial to consume fish oil either by eating fish or taking fish oil supplements, tablets, capsules, or pills during pregnancy for the overall development of the child and the well-being of the mother. However, it should be noted that fish oil obtained from the liver of the fish, example – cod liver oil, should not be consumed during pregnancy as cod liver oil is high in retinol and vitamin A, which are usually known to cause birth defects.
Many people focus on the dosage of fish oil to take, like 1000 mg or 1200 mg, but it is the omega-3s that matter. This is where the benefits of fish oil are found. The two types of omega-3 fatty acids to focus on are EPA and DHA. These omega-3s are naturally found in oily fish like salmon, halibut, sardines and anchovies, and are the very reason why fish oil supplements have received such high praise.
The #1 Pharmacist Recommended Omega-3/Fish Oil brand,* Nature Made fish oil supply comes from deep ocean waters, not farm-raised fish. State-of-the-art purification processes remove mercury and ensure high levels of fish oil purity and concentration, guaranteed to pass the stringent standards of the Global Organization for EPA and DHA Omega-3 Voluntary Monograph.‡

Omega-3s have been studied in various mood disorders, such as postpartum depression, with some promising results. In bipolar disorder (manic depression), the omega-3s may be most effective for the depressed phase rather than the manic phase of the illness. The omega-3s have also been proposed to alleviate or prevent other psychiatric conditions including schizophrenia, borderline personality disorder, obsessive compulsive disorder, and attention deficit disorder. However, there is still not enough evidence to recommend the omega-3s in these conditions.

According to the 2012 National Health Interview Survey, which included a comprehensive survey on the use of complementary health approaches in the United States, fish oil supplements are the nonvitamin/nonmineral natural product most commonly taken by both adults and children. The survey findings indicated that about 7.8 percent of adults (18.8 million) and 1.1 percent of children age 4 to 17 (664,000) had taken a fish oil supplement in the previous 30 days.
Omega-3s are generally safe and well tolerated. Stomach upset and “fishy taste” have been the most common complaints, but they are less frequent now thanks to manufacturing methods that reduce impurities. Past concerns about omega-3s increasing the risk of bleeding have been largely disproven, but caution is still advised in people taking blood thinners or who are about to undergo surgery. As mentioned, caution is needed in people with bipolar disorder to prevent cycling to mania. Because omega-3s are important to brain development, and pregnancy depletes omega-3 in expectant mothers, supplementation should theoretically benefit pregnant women and their children. Fish consumption in pregnancy is supported by the FDA, but because we do not have long-term data on safety or optimal dosing of omega-3s in pregnancy, expectant mothers should consider omega-3 supplements judiciously.
36. Marchioli R, Barzi F, Bomba E, Chieffo C, Di Gregorio D, Di Mascio R, Franzosi MG, Geraci E, Levantesi G, Maggioni AP, et al. Early protection against sudden death by n-3 polyunsaturated fatty acids after myocardial infarction: time-course analysis of the results of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI)-Prevenzione. Circulation. 2002;105:1897–903. [PubMed]
Since 2004, scientists have been suggesting that the omega-3 index be used as a way to measure a person’s risk of cardiovascular disease, in a similar way to how cholesterol levels are used today (1). A recent study funded by the National Institutes for Health even indicated that the omega-3 index could be a better predictor of death risk than serum cholesterol levels (2).
The reason why fish oil could increase a man’s risk of prostate cancer is IMBALANCE. Like I said earlier, omega-6 fatty acids aren’t bad for you. In fact, if your diet contains too many omega-3 fatty acids, your immune system wouldn’t work very well because omega-3 and omega-6 fatty acids are meant to work in a system of checks and balances. Omega-3 fatty acids suppress inflammation, and omega-6 fatty acids promote inflammation, which actually supports your body’s natural system of defense like activating your white blood cells.
When taking fish oil, more is not always better. Remember that you want it to stay in a balanced ratio with omega-6 fats. For most people, I recommend a 1,000-milligram dose of fish oil daily as a good amount and the most scientifically studied dosage. I highly recommend not taking more than that unless directed to under the supervision of a doctor.
Omega-3 fats may also impact the development of arthritis. As far back as 1959, studies were published about the effectiveness of cod liver oil on arthritic patients. In the 1959 study, 93 percent of participants “showed major clinical improvement.” (73) While there is no evidence that high omega-3 levels can prevent the development of arthritis, it seems clear that they can reduce inflammation that causes the typical bone and joint pain experienced in the disease. (74)
Australian researchers published results of a study examining the effects of fish oil on weight loss in combination with diet and exercise in the May 2007 issue of American Journal of Clinical Nutrition. The results show that a combination of fish oil supplements and regular exercise can reduce body fat while also improving heart and metabolic health. The fish supplementation group had lowered triglycerides, increased HDL cholesterol and improved blood flow. Overall, adding fish oil to a current exercise program (and a overall healthy lifestyle) looks like it can decrease body fat as well as cardiovascular disease risk. (32)

However, this difference in the length of the carbon chain gives these two types of omega-3s significant characteristics. EPA and DHA are long-chain fatty acids, while ALA is a short-chain fatty acid. The long-chain fatty acids are more important for cellular health. Another omega-3 fat, docosapentaenoic acid (DPA) can also be better synthesized by your body by elongating EPA.
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.
A new Cochrane systematic review, published today in the Cochrane Library, combines the results of seventy-nine randomised trials involving 112,059 people. These studies assessed effects of consuming additional omega 3 fat, compared to usual or lower omega 3, on diseases of the heart and circulation. Twenty-five studies were assessed as highly trustworthy because they were well designed and conducted.

Meanwhile, blood levels of DHA and EPA are very transitory, reflecting what an individual consumed only recently, while of course prostate cancer has a markedly longer progression. The study was not designed to isolate omega oil :: prostate cancer relationships, so conclusion would be weak. Seems likely to me that when faced with a serious disease, men suddenly begin to try living “right” in a hurry.
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.
Jump up ^ Ilse Schreiber: Die Schwestern aus Memel (1936), quoted, and extract translated in: Strzelczyk, Florentine (2014). "16: 'Fighting against Manitou': German Identity and Ilse Schreiber's Canada Novels Die Schwestern aus Memel (1936) and Die Flucht in Paradies (1939)". In McFarland, Rob; James, Michelle Stott. Sophie Discovers Amerika: German-Speaking Women Write the New World. Studies in German Literature Linguistics and Culture. 148. Boydell & Brewer. p. 207. ISBN 9781571135865. Hoffentlich zogen die Eltern in eine Gegend, wo es recht viele Eingeborene gab. Indianer, die nur von Jagd und Fischfang leben. Ach, und womöglich Eskimos, die sich mit Tran einschmieren, um sich gegen die Kälte zu schützen und rohes Fleisch essen [...]. [She hoped her parents would move to an area where there were many aboriginals. Indians who live solely by hunting and fishing. Oh, and if possible Eskimos who smear themselves with fish oil to protect themselves from the cold, and who eat raw meat.]
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.
To evaluate the potential placebo effect, we made further subgrouping analyses. In the subgroups of studies using placebo controls, the omega-3 PUFAs still revealed a consistent positive anxiolytic association with anxiety symptoms. These phenomena meant that the anxiolytic effect of omega-3 PUFAs is probably not entirely owing to the placebo effect.

Unintended weight loss is a problem that many patients with AD may face, and EPA+DHA supplementation has had a positive effect on weight gain in patients with AD. In a study using EPA+DHA supplementation, patients' weight significantly increased by 0.7 kg in the EPA+DHA treatment group at 6 mo (P = 0.02) and by 1.4 kg at 12 mo (P < 0.001) and was observed mainly in patients with a BMI <23 at the study start (54). This means that those patients with a lower BMI preferentially gained weight compared with those patients already with a higher BMI.
A report by the Harvard Medical School studied five popular brands of fish oil, including Nordic Ultimate, Kirkland and CVS. They found that the brands had "negligible amounts of mercury, suggesting either that mercury is removed during the manufacturing of purified fish oil or that the fish sources used in these commercial preparations are relatively mercury-free".[66]
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.
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.
The US National Institutes of Health lists three conditions for which fish oil and other omega-3 sources are most highly recommended: hypertriglyceridemia (high triglyceride level), preventing secondary cardiovascular disease, and hypertension (high blood pressure). It then lists 27 other conditions for which there is less evidence. It also lists possible safety concerns: "Intake of 3 grams per day or greater of omega-3 fatty acids may increase the risk of bleeding, although there is little evidence of significant bleeding risk at lower doses. Very large intakes of fish oil/omega-3 fatty acids may increase the risk of hemorrhagic (bleeding) stroke."[12]
We've been taking Omega 3 supplement as recommended anti inflammatory and did helps a lot in keeping our arthritis(RA) at bay. We had been discussing with our doctors on what is the recommended dose of Omega 3 that we can take. We have been taking these gel caps since - Very informative article most specially the discussions on the effect of both EPA and DHA.

Kabir, M., Skurnik, G., Naour, N., Pechtner, V., Meugnier, E., Rome, S., Quignard-Boulange, A., Vidal, H., Slama, G., Clement, K., Guerre-Millo, M., and Rizkalla, S. W. Treatment for 2 mo with n 3 polyunsaturated fatty acids reduces adiposity and some atherogenic factors but does not improve insulin sensitivity in women with type 2 diabetes: a randomized controlled study. Am.J.Clin.Nutr. 2007;86(6):1670-1679. View abstract.
EPA and DHA  stand for eicosapentaenoic acid and docosahexaenoic acid respectively. These fatty acids are omega-3 fats, which are found in cold water fish. EPA DHA are highly unsaturated fats because they contain six and five double bonds on their long structural chains. These polyunsaturated fats play a very important role with the function of our bodies.
Birch, E. E., Carlson, S. E., Hoffman, D. R., Fitzgerald-Gustafson, K. M., Fu, V. L., Drover, J. R., Castaneda, Y. S., Minns, L., Wheaton, D. K., Mundy, D., Marunycz, J., and Diersen-Schade, D. A. The DIAMOND (DHA Intake And Measurement Of Neural Development) Study: a double-masked, randomized controlled clinical trial of the maturation of infant visual acuity as a function of the dietary level of docosahexaenoic acid. Am J Clin Nutr 2010;91(4):848-859. View abstract.

Because of the preliminary state of knowledge on the effects of omega-3 PUFA treatment on anxiety, we decided to include as many studies as possible and not to set further limitations on specific characteristics, such as length of study, diagnosis, omega-3 PUFA dosage, omega-3 PUFA preparation (EPA to DHA ratio), rated anxiety coding scale, or type of control. Therefore, we chose to make the inclusion criteria as broad as possible to avoid missing any potentially eligible studies. The inclusion criteria included clinical trials in humans (randomized or nonrandomized), studies investigating the effects of omega-3 PUFA treatment on anxiety symptoms, and formal published articles in peer-reviewed journals. The clinical trials could be placebo controlled or non–placebo controlled. The target participants could include healthy volunteers, patients with psychiatric illness, and patients with physical illnesses other than psychiatric illnesses. The exclusion criteria included case reports or series, animal studies or review articles, and studies not investigating the effects of omega-3 PUFA treatment on anxiety symptoms. We did not set any language limitation to increase the number of eligible articles. Figure 1 shows the literature search and screening protocol.
EPA and DHA are vital nutrients and may be taken to maintain healthy function of the following: brain and retina: DHA is a building block of tissue in the brain and retina of the eye. It helps with forming neural transmitters, such as phosphatidylserine, which is important for brain function. DHA is found in the retina of the eye and taking DHA may be necessary for maintaining healthy levels of DHA for normal eye function.
6. Krauss-Etschmann S, Shadid R, Campoy C, Hoster E, Demmelmair H, Jimenez M, Gil A, Rivero M, Veszpremi B, Decsi T, et al. Effects of fish-oil and folate supplementation of pregnant women on maternal and fetal plasma concentrations of docosahexaenoic acid and eicosapentaenoic acid: a European randomized multicenter trial. Am J Clin Nutr. 2007;85:1392–400. [PubMed]
Dioxins and PCBs may be carcinogenic at low levels of exposure over time. These substances are identified and measured in one of two categories, dioxin-like PCBs and total PCBs. While the U.S. FDA has not set a limit for PCBs in supplements, the Global Organization for EPA and DHA (GOED) has established a guideline allowing for no more than 3 picograms of dioxin-like PCBs per gram of fish oil. In 2012, samples from 35 fish oil supplements were tested for PCBs. Trace amounts of PCBs were found in all samples, and two samples exceeded the GOED‘s limit.[52] Although trace amounts of PCBs contribute to overall PCB exposure, claims the amounts reported by tests it ordered on fish oil supplements are far below those found in a single typical serving of fish.[52]
Irish AB, Viecelli AK, Hawley CM, et al; Omega-3 Fatty Acids (Fish Oils) and Aspirin in Vascular Access Outcomes in Renal Disease (FAVOURED) Study Collaborative Group. Effect of fish oil supplementation and aspirin use on arteriovenous fistula failure in patients requiring hemodialysis: A randomized clinical trial. JAMA Intern Med. 2017;177(2):184-193. View abstract.
Nielsen, A. A., Jorgensen, L. G., Nielsen, J. N., Eivindson, M., Gronbaek, H., Vind, I., Hougaard, D. M., Skogstrand, K., Jensen, S., Munkholm, P., Brandslund, I., and Hey, H. Omega-3 fatty acids inhibit an increase of proinflammatory cytokines in patients with active Crohn's disease compared with omega-6 fatty acids. Aliment.Pharmacol.Ther. 2005;22(11-12):1121-1128. View abstract.