Your best way to achieve a good balance of omega-3 and omega-6 is by getting your fish oil from wild-caught fish like salmon. However, I still think it is beneficial for some to supplement with a high-quality omega-3 fish oil or cod liver oil. Plus, cold water fish are frequently contaminated with mercury and pesticide residues, making it very difficult to safely achieve recommended levels.

When it comes to fat, there's one type you don’t want to cut back on: omega-3 fatty acids. Two crucial ones -- EPA and DHA -- are primarily found in certain fish. ALA (alpha-linolenic acid), another omega-3 fatty acid, is found in plant sources such as nuts and seeds. Not only does your body need these fatty acids to function, but also they deliver some big health benefits.
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.

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
One of the most well-known benefits of omega-3s are the way they positively affect risk factors associated with heart disease. That’s one reason the American Heart Association is very clear about encouraging people to get enough in their diets. (8) Heart disease and stroke are the leading causes of death worldwide, but communities who eat diets rich in fish have remarkably low instances of these diseases, which is at least partially due to their high omega-3 consumption. (9, 10)
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.]

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. 
These conversions occur competitively with omega−6 fatty acids, which are essential closely related chemical analogues that are derived from linoleic acid. They both utilize the same desaturase and elongase proteins in order to synthesize inflammatory regulatory proteins.[50] The products of both pathways are vital for growth making a balanced diet of omega−3 and omega−6 important to an individual's health.[77] A balanced intake ratio of 1:1 was believed to be ideal in order for proteins to be able to synthesize both pathways sufficiently, but this has been controversial as of recent research.[78]
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.
In my opinion, the key benefit of DHA lies in its unique spatial characteristics. As mentioned earlier, the extra double bond (six in DHA vs. five in EPA) and increased carbon length (22 carbons in DHA vs. 20 in EPA) means that DHA takes up takes up a lot more space than does EPA in the membrane. Although this increase in spatial volume makes DHA a poor substrate for phospholipase A2 as well as the COX and LOX enzymes, it does a great job of making membranes (especially those in the brain) a lot more fluid as the DHA sweeps out a much greater volume in the membrane than does EPA. This increase in membrane fluidity is critical for synaptic vesicles and the retina of the eye as it allows receptors to rotate more effectively thus increasing the transmission of signals from the surface of the membrane to the interior of the nerve cells. This is why DHA is a critical component of these highly fluid portions of the nerves (7). On the other hand, the myelin membrane is essentially an insulator so that relatively little DHA is found in that part of the membrane.
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
While fish oil has plenty of beneficial qualities, there is a lot of hype around its possible applications, and not all of them are accurate, so be wary when reading literature on this useful oil. Fish oil manufacturers have attempted to market it as a remedy for almost anything. We suggest that readers educate themselves fully before making an informed decision, rather than getting affected by both negative and positive propaganda about the beneficial applications of fish oil.
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]
There have been conflicting results reported about EPA and DHA and their use with regard to major coronary events and their use after myocardial infarction. EPA+DHA has been associated with a reduced risk of recurrent coronary artery events and sudden cardiac death after an acute myocardial infarction (RR, 0.47; 95% CI: 0.219–0.995) and a reduction in heart failure events (adjusted HR: 0.92; 99% CI: 0.849–0.999) (34–36). A study using EPA supplementation in combination with a statin, compared with statin therapy alone, found that, after 5 y, the patients in the EPA group (n = 262) who had a history of coronary artery disease had a 19% relative reduction in major coronary events (P = 0.011). However, in patients with no history of coronary artery disease (n = 104), major coronary events were reduced by 18%, but this finding was not significant (37). This Japanese population already has a high relative intake of fish compared with other nations, and, thus, these data suggest that supplementation has cardiovascular benefits in those who already have sufficient baseline EPA+DHA levels. Another study compared patients with impaired glucose metabolism (n = 4565) with normoglycemic patients (n = 14,080). Impaired glucose metabolism patients had a significantly higher coronary artery disease HR (1.71 in the non-EPA group and 1.63 in the EPA group). The primary endpoint was any major coronary event including sudden cardiac death, myocardial infarction, and other nonfatal events. Treatment of impaired glucose metabolism patients with EPA showed a significantly lower major coronary event HR of 0.78 compared with the non–EPA-treated impaired glucose metabolism patients (95% CI: 0.60–0.998; P = 0.048), which demonstrates that EPA significantly suppresses major coronary events (38). When looking at the use of EPA+DHA and cardiovascular events after myocardial infarction, of 4837 patients, a major cardiovascular event occurred in 671 patients (13.9%) (39). A post hoc analysis of the data from these diabetic patients showed that rates of fatal coronary heart disease and arrhythmia-related events were lower among patients in the EPA+DHA group than among the placebo group (HR for fatal coronary heart disease: 0.51; 95% CI: 0.27–0.97; HR for arrhythmia-related events: 0.51; 95% CI: 0.24–1.11, not statistically significant) (39). Another study found that there was no significant difference in sudden cardiac death or total mortality between an EPA+DHA supplementation group and a control group in those patients treated after myocardial infarction (40). Although these last 2 studies appear to be negative in their results, it is possible that the more aggressive treatment with medications in these more recent studies could attribute to this.
In another study, Australian researchers looked at whether giving infants added omega-3 fatty acids might improve health,4 including reducing their risk for heart disease. They gave 420 infants either an omega 3 supplement or olive oil from birth through six months, then revisited that at age 5 years to see if either group appeared healthier from a heart risk point of view.
According to the National Psoriasis Foundation, fish oil can aid in preventing or slowing heart disease, which is especially great for psoriasis and psoriatic arthritis sufferers who are at a higher risk of developing heart disease. (27) When it comes to using fish oil supplements for the alleviation of psoriasis symptoms, studies have been mixed with some showing improvement but others showing no effect. If you suffer from psoriasis, you may want to try a fish oil supplement, or else I highly recommend that you make sure to have fish rich in omega-3s regularly.
Human growth and intellectual development – DHA plays a very important role during fetal development, early infancy and old age. High concentrations of DHA are found in the brain and increase 300 to 500 percent in an infant’s brain during the last trimester of pregnancy. Adding DHA to a pregnant mother’s diet may be beneficial for the fetus’s brain development. Elderly people should also take EPA DHA, because as we get older, our bodies form less EPA and DHA, which may cause less mental focus and cognitive function. Taking EPA DHA also may help with mental abnormalities, such as Alzheimer’s disease and dementia.
The omega-3 index may also be helpful for assessing health risks beyond cardiovascular disease. Studies are currently investigating the relationship between omega-3 index levels and mental health issues, like depression (15, 16, 17), cognitive functioning (18, 19), body weight (20), as well as eye health issues, like macular degeneration (21), to name just a few.

Whilst EPA and DHA are both considered to be important regulators of immunity, platelet aggregation and inflammation, their health-influencing by-products arise from very different pathways and their effects in the body differ. DHA is the most abundant omega-3 fatty acid in cell membranes, present in all organs and most abundant in the brain and retina, playing an important structural role. EPA is present structurally only in minute quantities, always being utilised and under constant demand to be replaced. Whilst DHA provides mainly a structural role, it is becoming evident that EPA may be the dominant functional fatty acid out of the two in many areas of health and especially in inflammatory conditions.
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.
Fortier, M., Tremblay-Mercier, J., Plourde, M., Chouinard-Watkins, R., Vandal, M., Pifferi, F., Freemantle, E., and Cunnane, S. C. Higher plasma n-3 fatty acid status in the moderately healthy elderly in southern Quebec: higher fish intake or aging-related change in n-3 fatty acid metabolism? Prostaglandins Leukot.Essent.Fatty Acids 2010;82(4-6):277-280. View abstract.
Cashew nuts are a versatile, creamy nut, eaten on their own as a snack or used as a base for many vegan cheese substitutes. RXBAR, a healthy alternative to the standard sugar-loaded snack bar, uses cashews for several of its flavor varieties. And with delicious (and kid-friendly!) flavors like gingerbread, chocolate chip, or “Berry Blast,” these bars are a tasty way to add more cashews to any diet.
For preventing and reversing the progression of hardening of the arteries after angioplasty: 6 grams of fish oil daily starting one month before angioplasty and continuing for one months after, followed by 3 grams daily for 6 months thereafter has been used. Also, 15 grams of fish oil has been taken daily for 3 weeks before angioplasty and for 6 months thereafter.
Bergmann, R. L., Haschke-Becher, E., Klassen-Wigger, P., Bergmann, K. E., Richter, R., Dudenhausen, J. W., Grathwohl, D., and Haschke, F. Supplementation with 200 mg/day docosahexaenoic acid from mid-pregnancy through lactation improves the docosahexaenoic acid status of mothers with a habitually low fish intake and of their infants. Ann Nutr Metab 2008;52(2):157-166. View abstract.
^ 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.
^ 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.
Conflicts of interest comprise financial interests, activities, and relationships within the past 3 years including but not limited to employment, affiliation, grants or funding, consultancies, honoraria or payment, speaker's bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued.
Currently, there isn’t a set standard recommendation for how many omega-3s we need each day, but suggestions range from a fish oil dosage of 500 to 1,000 milligrams daily depending on whom you ask. How easy is it to get these recommended amounts? To give you an idea, there are more than 500 milligrams of total omega-3s in one can of tuna fish and one small serving of wild-caught salmon.
There have been numerous clinical trials looking mainly at death, stroke, and cardiac outcomes related to omega 3 consumption, either in food or in supplements. Now the Cochrane Library has published the largest systematic review of these studies to date. Unfortunately, the review shows little benefit from consuming omega 3 fatty acid. This is a fairly extensive review with good statistical power:
Bergmann, R. L., Haschke-Becher, E., Klassen-Wigger, P., Bergmann, K. E., Richter, R., Dudenhausen, J. W., Grathwohl, D., and Haschke, F. Supplementation with 200 mg/day docosahexaenoic acid from mid-pregnancy through lactation improves the docosahexaenoic acid status of mothers with a habitually low fish intake and of their infants. Ann Nutr Metab 2008;52(2):157-166. View abstract.
Funding/Support: The work was supported in part by grant 17H04253, Grant-in-Aid for Scientific Research (B) from the Japan Society for the Promotion of Science; grant 30-A-17 from the National Cancer Center Research and Development Fund; grants MOST106-2314-B-039-027-MY, 106-2314-B-038-049, 106-2314-B-039-031, 106-2314-B-039-035, 104-2314-B-039-022-MY2, and 104-2314-B-039-050-MY3 from the Ministry of Science and Technology, Taiwan; grant HRI-EX105-10528NI from the National Health Research Institutes, Taiwan; and grants CRS-106-063, DMR-107-202, and DMR-107-204 from the China Medical University, Taiwan.
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.
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.
Only fish and breast milk contain all the members of the omega-3 family, including its two main stars, EPA and DHA. Because Americans as a rule consume far too few omega-3s from fish or fish oil, it’s no surprise that the majority of Americans have low omega-3 index levels as well. A recent study of global omega-3 index levels found that an estimated 95% of Americans (with the exception of folks from Alaska) had an omega-3 index of 4 or below, putting them in the high risk category (5, 6, 7).
The University of East Anglia (UEA) is a UK Top 15 university. Known for its world-leading research and outstanding student experience, it was awarded Gold in the Teaching Excellence Framework and  is a leading member of Norwich Research Park, one of Europe’s biggest concentrations of researchers in the fields of environment, health and plant science.
Nakamura, N., Hamazaki, T., Ohta, M., Okuda, K., Urakaze, M., Sawazaki, S., Yamazaki, K., Satoh, A., Temaru, R., Ishikura, Y., Takata, M., Kishida, M., and Kobayashi, M. Joint effects of HMG-CoA reductase inhibitors and eicosapentaenoic acids on serum lipid profile and plasma fatty acid concentrations in patients with hyperlipidemia. Int J Clin Lab Res 1999;29(1):22-25. View abstract.