A group out of India conducted a study published in Cancer Chemotherapy and Pharmacology based on the premise that “fish oil rich in n-3 polyunsaturated fatty acids has been preferred to chemosensitize tumor cells to anti-cancer drugs.” The study found that using 5-Fluorouracil (5-FU) to treat colorectal cancer along with fish oil increased the survival rate in carcinogen-treated animals. Researchers also found that the fish oil ameliorated hematologic depression, along with gastrointestinal, hepatic and renal toxicity caused by the 5-FU. (15)
Today the only Food and Drug Administration (FDA)-approved form of dietary omega-3 FA supplement is Lovaza (omega-3-acid ethyl esters; GlaxoSmithKline), which contains 375 mg of DHA and 465 mg of EPA per 1 g capsule. The myriad of dietary supplements of fish oil, including Kosher capsules, vary from comparable content to insignificant amounts, and for the most part can include other fats and cholesterols. In comparison, to achieve approximately 1 g of EPA and DHA in a meal, 12 ounces of canned light tuna, 2 to 3 ounces of sardines, 1.5 to 2.5 ounces of farmed Atlantic salmon, or 20 ounces of farmed catfish must be consumed (Table 1).65 Unfortunately, potentially high levels of harmful pollutants offset this source of omega-3 FA. The FDA action level for unacceptably high mercury content in fish is 1.0 μg/g. The mercury level in most fish is at or below 0.1 μg/g, but tilefish, swordfish, and king mackerel have high levels of mercury. The majority of fish species also contain <100 ng/g of polychlorinated biphenyls, which is below the FDA action level of 2000 ng/g. Dioxins, which do not have FDA action levels, are present in the majority of marine life.66
Unsafe for children. Fish oil supplements are not considered safe for children. Too much of this fat in their system can lead to a chemical imbalance in the brain which could stunt healthy growth and development. Because of this, and the possible exposure to polychlorinated biphenyls, methylmercury and other toxins which are found in some sources of fish, it is not recommended that women who are pregnant take excessive amounts of fish oil. Servings of fish should be limited to six ounces per week and they should refrain from using fish oil or other fatty acid supplement pills. Children should not consume more than two ounces of fish per week to avoid overexposure to these chemicals. Now you know although fish oil can benefit human beings a lot, fish oil side effects should never be neglected for the sake of your safety. 
DHA is one of the most prevalent fatty acids in the brain. This could partly explain why our brains do better with a greater supply. A Rush Institute for Healthy Aging study analyzed fish-eating patterns of more than 800 men and women, ages 65 to 94. Those eating fish at least once a week were much less likely to develop Alzheimer's disease than those who turned up their nose at it.

Fish oil supplements came under scrutiny in 2006, when the Food Standards Agency in the UK and the Food Safety Authority of Ireland reported PCB levels that exceeded the European maximum limits in several fish oil brands,[60][61] which required temporary withdrawal of these brands. To address the concern over contaminated fish oil supplements, the International Fish Oil Standards (IFOS) Program, a third-party testing and accreditation program for fish oil products, was created by Nutrasource Diagnostics Inc. in Guelph, Ontario, Canada.[62]
The GISSI-Heart Failure trial was the first blinded, randomized trial to assess the efficacy of fish oil supplements in patients with heart failure.51 The trial enrolled 7046 subjects with heart failure; 60% with New York Heart Association class II symptoms and 40% with a history of MI. The majority of patients were on a standard heart failure regimen, including angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, beta-blockers, and spironolactone, but only 22% were on a statin. At an average of 3.9 years, the coprimary end points of death and death or hospital admission for cardiovascular reasons were reduced by approximately 9% with fish oil supplementation. Sudden cardiac death, a secondary end-point, showed a statistically nonsignificant relative risk reduction of 7% with fish oil. There was also a reduction in 2 other arrhythmia-related secondary end-points: first hospitalization for ventricular arrhythmia and presumed arrhythmic death.

After the age of five, the development of the brain and CNS starts to reduce and the body’s need for DHA reduces. This is a good time to increase EPA in the diet, as studies show that EPA can help with childhood behaviour and academic performance, as well as focus, attention and reducing aggression. Dry skin conditions, asthma and allergies are also common in children and good levels of EPA at this time can help reduce the inflammation associated with these issues.
High blood pressure. Fish oil seems to slightly lower blood pressure in people with moderate to very high blood pressure. Some types of fish oil might also reduce blood pressure in people with slightly high blood pressure, but results are inconsistent. Fish oil seems to add to the effects of some, but not all, blood pressure-lowering medications. However, it doesn't seem to reduce blood pressure in people with uncontrolled blood pressure who are already taking blood pressure-lowering medications.
Brussels sprouts are a cruciferous vegetable bursting with vitamin K, vitamin C, and a healthy dose of omega-3 fatty acids. With their strong flavor and smell, however, they’re not always loved (or even tolerated) by children or adults with ADHD. If someone in your house considers sprouts the enemy, try this recipe — honey, cranberries, and parmesan cheese give these Brussels sprouts a sweet and savory flavor that even picky eaters love.
My initial interest in omga-3 was an article by Dr Andrew Stoll in Harvard about May 99, One of my bipolar patients had extreme OCD related to HIV which was not relevant to her. I put her on 9.6g of fish oil and continued her on her regular medication. She was well for the next 3 years with no obvious mental health problem when she was attending here.
Docosahexaenoic acid (DHA) found primarily in fish oil, this is the ultimate form of fatty acid in humans. Most people get far too little of this all-important fatty acid, especially since the conversion of ALA to DHA is slow and minimally yielding. Getting a daily dose of of DHA (600 to 1000 mg) from supplements is preferable to reap the health benefits. You have a choice of taking a fish oil supplement or one derived from algae or krill, a shrimp-like crustacean.
It’s no surprise that fish — particularly cold-water fatty fish like salmon, mackerel, and anchovies — are rich in omega-3s. It’s called fish oil for a reason, right? Mackerel, for instance, may have more than 3300 mg of omega-3 per serving — that’s more than 6 times the recommended per day dose for healthy adults. Not a huge fish connoisseur? Try some of the quick, simple recipes in Cooking with Fish Like a Pro, an accessible collection of fish recipes to suit every palate.
Flaxseed (or linseed) (Linum usitatissimum) and its oil are perhaps the most widely available botanical source of the omega−3 fatty acid ALA. Flaxseed oil consists of approximately 55% ALA, which makes it six times richer than most fish oils in omega−3 fatty acids.[126] A portion of this is converted by the body to EPA and DHA, though the actual converted percentage may differ between men and women.[127]
Keep in mind that APA found in plant-based foods takes a lot of energy for your body to convert to EPA and DHA. I understand that many people following a vegan diet struggle with the concept of fish oil or eating fish, but animal products contain the necessary omega-3 fatty acids to allow your body to absorb and synthesize what you take in. However, there are plant-based options — you’ll just need more APA because of the way your body processes the medium-chain fatty acid.
Reduce Metabolic Syndrome Symptoms: The cluster of risk factors known as metabolic syndrome includes abdominal obesity, high blood sugar, high triglycerides, high blood pressure and low HDL cholesterol. These risk factors are indicative of a high chance you might develop heart disease, stroke or diabetes. Multiple studies have found omega-3 supplementation improve the symptoms of metabolic syndrome and may help to protect you from the related diseases. (22, 23, 24, 25)
^ Jump up to: a b Aursand, Marit; Mozuraityte, Revilija; Hamre, Kristin; Knutsen, Helle; Maage, Amund; Arukwe, Augustine (2011). Description of the processes in the value chain and risk assessment of decomposition substances and oxidation products in fish oils (PDF). Norwegian Scientific Committee for Food Safety. ISBN 978-82-8259-035-8. Retrieved 19 October 2012.[page needed]
56. Davidson MH, Stein EA, Bays HE, et al. COMBination of prescription Omega-3 with Simvastatin (COMBOS) Investigators. Efficacy and tolerability of adding prescription omega-3 fatty acids 4 g/d to simvastatin 40 mg/d in hypertriglyceridemic patients: an 8-week, randomized, double-blind, placebo-controlled study. Clin Ther. 2007;29:1354–1367. [PubMed]
First, all Omega-3 products are not alike. Here's what I learned about Omega-3 from my research. The "3" relates to three sources of Omega-3 fatty acids. Two of them, DHA and EPA are found in marine products such as fish and krill. The third source, ALA, is from plants. So with fish oil you are getting two of the three sources at once. That makes sense to me as a good reason to take Omega-3 fish oil. You will also note below that many of the reasons we choose to take Omega-3 do not occur with plant-based products.
Results  In total, 1203 participants with omega-3 PUFA treatment (mean age, 43.7 years; mean female proportion, 55.0%; mean omega-3 PUFA dosage, 1605.7 mg/d) and 1037 participants without omega-3 PUFA treatment (mean age, 40.6 years; mean female proportion, 55.0%) showed an association between clinical anxiety symptoms among participants with omega-3 PUFA treatment compared with control arms (Hedges g, 0.374; 95% CI, 0.081-0.666; P = .01). Subgroup analysis showed that the association of treatment with reduced anxiety symptoms was significantly greater in subgroups with specific clinical diagnoses than in subgroups without clinical conditions. The anxiolytic effect of omega-3 PUFAs was significantly better than that of controls only in subgroups with a higher dosage (at least 2000 mg/d) and not in subgroups with a lower dosage (<2000 mg/d).
For example, large predatory fish like shark, swordfish, king mackerel, tilefish and albacore tuna can contain high levels of methyl mercury, a toxin that would override any health benefit, especially for the developing brains of fetuses and young children as well as for adults, Dr. Nesheim and Marion Nestle, professor emerita of nutrition, food studies and public health at New York University, noted in 2014 in an editorial in the American Journal of Clinical Nutrition. (Levels of mercury and other contaminants in fish have since declined somewhat but are not negligible.)
If, however, we want to target the actions and benefits of either fat for more intensive support or clinical use, we need to alter the natural 1.5:1 EPA:DHA ratio found in most omega-3 sources such as fish oil – which is when concentrated supplements are especially useful. Certain forms of omega-3 called ethyl-ester and re-esterified triglyceride give nature a helping hand – allowing us to achieve targeted ratios of specific fatty acids at high concentration and physiologically active doses.
Gerber, J. G., Kitch, D. W., Fichtenbaum, C. J., Zackin, R. A., Charles, S., Hogg, E., Acosta, E. P., Connick, E., Wohl, D., Kojic, E. M., Benson, C. A., and Aberg, J. A. Fish oil and fenofibrate for the treatment of hypertriglyceridemia in HIV-infected subjects on antiretroviral therapy: results of ACTG A5186. J.Acquir.Immune.Defic.Syndr. 4-1-2008;47(4):459-466. View abstract.
Lok CE, Moist L, Hemmelgarn BR, Tonelli M, Vazquez MA, Dorval M, Oliver M, Donnelly S, Allon M, Stanley K; Fish Oil Inhibition of Stenosis in Hemodialysis Grafts (FISH) Study Group. Effect of fish oil supplementation on graft patency and cardiovascular events among patients with new synthetic arteriovenous hemodialysis grafts: a randomized controlled trial. JAMA 2012;307(17):1809-16. View abstract.
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]
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.
Recently another Omega-3 fatty acid, DPA (Docosapentaenoic Acid) has been discussed more frequently in the scientific community, as a new and very potent Omega-3 fatty acid. Previously thought to work in through EPA and DHA we are now learning it has very distinct functions in the body. All three of these polyunsaturated fats play an important role in the functioning of our bodies.

Omega-3 is a group of long-chain polyunsaturated fatty acids, perhaps most notably found in fatty fish. As science parses the biological actions of nutrients, it turns out that omega-3 fats do many good things for the body and the brain. Known as an "essential" fatty acid, meaning the body must take it in from food sources, omega-3 is important to human metabolism.
Throughout their history, the Council for Responsible Nutrition and the World Health Organization have published acceptability standards regarding contaminants in fish oil. The most stringent current standard is the International Fish Oils Standard.[108][non-primary source needed] Fish oils that are molecularly distilled under vacuum typically make this highest-grade; levels of contaminants are stated in parts per billion per trillion.[citation needed][109]

Your body also needs omega-6s, another type of fatty acid, to function properly and prevent disease. Unfortunately, these are found in much more abundance than omega-3s in the standard American diet, although your body craves a 1:1 ratio to keep inflammation low. Most modern diets contain a ratio closer to 20:1 or 30:1 omega-6 to omega-3 fatty acids.
Fish oil can be consumed in various ways such as capsules or can be included in daily meals. The dosage should not exceed 3 fish oil capsules per day. 1000mg of fish oil contains approximately 300mg omega-3 fatty acids so you can accordingly use the amount of fish oil in your meals. A daily intake of 3000mg or less is safe for all. Pregnant and lactating women can consume approximately 3200 mg per day.

The Cochrane researchers found that increasing long-chain omega 3 provides little if any benefit on most outcomes that they looked at. They found high certainty evidence that long-chain omega 3 fats had little or no meaningful effect on the risk of death from any cause. The risk of death from any cause was 8.8% in people who had increased their intake of omega 3 fats, compared with 9% in people in the control groups.
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.
56. Davidson MH, Stein EA, Bays HE, et al. COMBination of prescription Omega-3 with Simvastatin (COMBOS) Investigators. Efficacy and tolerability of adding prescription omega-3 fatty acids 4 g/d to simvastatin 40 mg/d in hypertriglyceridemic patients: an 8-week, randomized, double-blind, placebo-controlled study. Clin Ther. 2007;29:1354–1367. [PubMed]

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.

Finally, it is often assumed since there are not high levels of EPA in the brain, that it is not important for neurological function. Actually it is key for reducing neuro-inflammation by competing against AA for access to the same enzymes needed to produce inflammatory eicosanoids. However, once EPA enters into the brain it is rapidly oxidized (2,3). This is not the case with DHA (4). The only way to control cellular inflammation in the brain is to maintain high levels of EPA in the blood. This is why all the work on depression, ADHD, brain trauma, etc. have demonstrated EPA to be superior to DHA (5).
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]

Your body can convert some ALA into EPA and then DHA, but not enough to meet all your body’s needs but the best way to assure you are getting enough heart healthy fats is to eat foods high in the omega 3 fats, and if you can’t or don’t get enough of these necessary fats in your diet, you might consider taking an omega 3 supplement to boost these needed fats. More on this later.

In the United States, the Institute of Medicine publishes a system of Dietary Reference Intakes, which includes Recommended Dietary Allowances (RDAs) for individual nutrients, and Acceptable Macronutrient Distribution Ranges (AMDRs) for certain groups of nutrients, such as fats. When there is insufficient evidence to determine an RDA, the institute may publish an Adequate Intake (AI) instead, which has a similar meaning, but is less certain. The AI for α-linolenic acid is 1.6 grams/day for men and 1.1 grams/day for women, while the AMDR is 0.6% to 1.2% of total energy. Because the physiological potency of EPA and DHA is much greater than that of ALA, it is not possible to estimate one AMDR for all omega−3 fatty acids. Approximately 10 percent of the AMDR can be consumed as EPA and/or DHA.[105] The Institute of Medicine has not established a RDA or AI for EPA, DHA or the combination, so there is no Daily Value (DVs are derived from RDAs), no labeling of foods or supplements as providing a DV percentage of these fatty acids per serving, and no labeling a food or supplement as an excellent source, or "High in..."[citation needed] As for safety, there was insufficient evidence as of 2005 to set an upper tolerable limit for omega−3 fatty acids,[105] although the FDA has advised that adults can safely consume up to a total of 3 grams per day of combined DHA and EPA, with no more than 2 g from dietary supplements.[8]
Augood, C., Chakravarthy, U., Young, I., Vioque, J., de Jong, P. T., Bentham, G., Rahu, M., Seland, J., Soubrane, G., Tomazzoli, L., Topouzis, F., Vingerling, J. R., and Fletcher, A. E. Oily fish consumption, dietary docosahexaenoic acid and eicosapentaenoic acid intakes, and associations with neovascular age-related macular degeneration. Am J Clin Nutr 2008;88(2):398-406. View abstract.
Widenhorn-Müller  K, Schwanda  S, Scholz  E, Spitzer  M, Bode  H.  Effect of supplementation with long-chain ω-3 polyunsaturated fatty acids on behavior and cognition in children with attention deficit/hyperactivity disorder (ADHD): a randomized placebo-controlled intervention trial.  Prostaglandins Leukot Essent Fatty Acids. 2014;91(1-2):49-60. doi:10.1016/j.plefa.2014.04.004PubMedGoogle ScholarCrossref
Nielsen, G. L., Faarvang, K. L., Thomsen, B. S., Teglbjaerg, K. L., Jensen, L. T., Hansen, T. M., Lervang, H. H., Schmidt, E. B., Dyerberg, J., and Ernst, E. The effects of dietary supplementation with n-3 polyunsaturated fatty acids in patients with rheumatoid arthritis: a randomized, double blind trial. Eur J Clin Invest 1992;22(10):687-691. View abstract.