Good for you for eating healthily! Sadly, many people do not like omega-3 containing foods such as fish, and for these people, supplementation may be a good alternative to obtain omega-3. As a clinical investigator, my research focuses on study supplements, which is what I was asked to cover in this article. I’m all for healthy eating, but not everyone can afford it or wants to eat certain foods, and this is perhaps why supplements are so popular.

Jump up ^ Miller M, Stone NJ, Ballantyne C, Bittner V, Criqui MH, Ginsberg HN, Goldberg AC, Howard WJ, Jacobson MS, Kris-Etherton PM, Lennie TA, Levi M, Mazzone T, Pennathur S (May 2011). "Triglycerides and cardiovascular disease: a scientific statement from the American Heart Association". Circulation. 123 (20): 2292–333. doi:10.1161/CIR.0b013e3182160726. PMID 21502576.

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.)
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.
Pay attention to the quality of fish oil when purchasing it. It is obtained from almost all fishes – fresh water, farm, ocean, deep sea and shallow sea fish. All these fishes can be contaminated with toxic compounds such as mercury, arsenic, lead, forms of calcium, furans, dioxins, PCBs, and methylmercury, and can negatively affect the human body. Therefore, the fish oil used must be pure. Many companies sell ultra refined or distilled fish oil, but you should always check if the standards have been followed and research on the company or the product before adding it to your diet.
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.
After just seven days, those supplementing with krill had their CRP levels reduced by 19.3%, while in the placebo group, CRP levels rose by 15.7%. Even more impressive, the krill benefit was long-lasting. The krill group’s CRP levels continued to fall by 29.7% at 14 days, and 30.9% at 30 days. More importantly from the patients’ points of view, the krill oil supplement reduced pain scores by 28.9%, reduced stiffness by 20.3%, and reduced functional impairment by 22.8%.
Gajos G1, Rostoff P, Undas A, et al. Effects of polyunsaturated omega-3 fatty acids on responsiveness to dual antiplatelet therapy in patients undergoing percutaneous coronary intervention: the OMEGA-PCI (OMEGA-3 fatty acids after pci to modify responsiveness to dual antiplatelet therapy) study. J Am Coll Cardiol. 2010 Apr 20;55(16):1671-8. View abstract.
One reason omega-3 fatty acids may be so beneficial to this many aspects of health could be that they help decrease system-wide inflammation. (49, 50, 51, 52, 53) Inflammation is at the root of most diseases and is related to the development of nearly every major illness, so by eating a nutrient-dense, anti-inflammatory diet, you give your body its best chance to fight disease like it was designed to do.
Fish oil has been shown to have a direct electrophysiological effect on the myocardium. Initial experience with animal ischemia models demonstrated that the ventricular fibrillation threshold was increased in both animals fed or infused with omega-3 FA.23,24 This progressed to a demonstration, on a cellular and ion channel level, that omega-3 FA reduce both sodium currents and L-type calcium currents.25–29 It is hypothesized that during ischemia, a reduction in the sodium ion current protects hyperexcitable tissue, and a reduction in the calcium ion current reduces arrhythmogenic depolarizing currents.30
Brain function and vision rely on dietary intake of DHA to support a broad range of cell membrane properties, particularly in grey matter, which is rich in membranes.[61][62] A major structural component of the mammalian brain, DHA is the most abundant omega−3 fatty acid in the brain.[63] It is under study as a candidate essential nutrient with roles in neurodevelopment, cognition, and neurodegenerative disorders.[61]
The bottom line of all that is that there was no clear health benefit from consuming omega-3 fatty acids in food or supplements. There was a suggestion of a possible benefit from LCn3 on cardiac events, but this did not hold up when they took into consideration the quality of the evidence. The better trials, with less risk of bias, tended to be negative.
Due to the presence of Omega-3 fatty acids, fish oil has been promoted for relieving depression, sadness, anxiety, restlessness, mental fatigue, stress, decreased sexual desire, suicidal tendencies, and other nervous disorders. Researchers at the Case Western Reserve University School of Medicine in Cleveland, Ohio, in their research publication titled “Fish Oils and Bipolar Disorder: A Promising but Untested Treatment”, state that fish oil can be useful in mood stabilization and the treatment of bipolar disorders. It is unsurprising, therefore, that countries where fish is frequently eaten, have a low incidence of depression. Similarly, research conducted on prisoners has shown that when prisoners were given seafood containing a higher amount of omega-3 fatty acids, there was a significant drop in the homicide rate and the frequency of violence. Intake of fish is also a good remedy for depression. Findings of a research study suggest that fish consumption may be beneficial for women’s mental health and reduces the risk of developing depression in women.
Cochrane lead author, Dr. Lee Hooper from the University of East Anglia, UK said: “We can be confident in the findings of this review which go against the popular belief that long-chain omega 3 supplements protect the heart. This large systematic review included information from many thousands of people over long periods.  Despite all this information, we don’t see protective effects.
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.
Agency for Healthcare Research and Quality. Effects of Omega-3 Fatty Acids on Lipids and Glycemic Control in Type II Diabetes and the Metabolic Syndrome and on Inflammatory Bowel Disease, Rheumatoid Arthritis, Renal Disease, Systemic Lupus Erythematosus, and Osteoporosis. AHRQ Publication No. 04-E012-1; 2004. Available at: https://archive.ahrq.gov/downloads/pub/evidence/pdf/o3lipid/o3lipid.pdf. (Accessed February 7, 2017).
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
A study published in Brain Research shows how far-reaching fish oil can be for people with diabetes. Researches found that fish oil can help reduce the risk of diabetics from developing cognitive deficit because it protects the hippocampus cells from being destroyed. The study also showed that fish oil could help reduce oxidative stress, which plays a central role in the development of diabetes complications, both microvascular and cardiovascular. (22)
So back to fish oil in general. The major fish oil benefits include decreasing the risk of heart disease and stroke while also helping reduce symptoms of depression, hypertension, attention deficit hyperactivity disorder (ADHD), joint pain, arthritis and chronic skin ailments like eczema. (2) Fish oil intake has also been associated with aiding the body in weight loss, fertility, pregnancy and increased energy. Prescription fish oil has even been approved by the FDA to lower unhealthy high triglyceride levels. (3)
46. Gajos G, Rostoff P, Undas A, Piwowarska W. Effects of polyunsaturated omega-3 fatty acids on responsiveness to dual antiplatelet therapy in patients undergoing percutaneous coronary intervention: the OMEGA-PCI (OMEGA-3 fatty acids after pci to modify responsiveness to dual antiplatelet therapy) study. J Am Coll Cardiol. 2010;55:1671–8. [PubMed]

Could you be deficient in omega-3s? The University of Maryland Medical Center says that the symptoms “include fatigue, poor memory, dry skin, heart problems, mood swings or depression, and poor circulation.” They also warn against a poor omega-3 to omega-6 ratio, cautioning readers that it may be “associated with worsening inflammation over time.” (6)


Our scientists also focused on each oil’s freshness, measured by the degree of oxidation. Oxidation occurs in two phases: primary (measured by peroxide values) and secondary (measured by p-anisidine values). Total oxidation is formalized into a quantitative score, TOTOX. While Labdoor conducted tests of both primary and secondary oxidation, advances in rancidity testing confirm that added flavors–particularly added citrus flavors prevalent in liquid formulations–skew p-anisidine values and result in false positive outcomes. Until analytical techniques measuring p-anisidine values that are able to account for added flavors are established, Labdoor will use peroxide values as the primary indicator of freshness. All products recorded measurable levels of oxidation, with the average product recording a peroxide values of 3.7 meq/kg. 14/51 products recorded peroxide levels at or above the upper limit (10 meq/kg).
Of great clinical importance, EPA and DHA supplementation during pregnancy has been associated with longer gestation and increased concentrations of EPA and DHA in fetal tissues (21). In 2005, preterm births accounted for 12.7% of all births in the United States, increasing the likelihood of health complications (22). Carrying a baby to term is very important because prematurity is the cause of various infant diseases and can lead to death; preterm delivery is an underlying factor for 85% of the deaths of normally formed infants (23). One mechanism by which EPA and DHA may decrease the incidence of preterm birth is by decreasing prostaglandin E2 and prostaglandin F2α production, therefore reducing inflammation within the uterus, which could be associated with preterm labor (21, 24). Several studies investigated EPA and DHA intake during pregnancy and its correlation with longer gestation. Conclusions were that EPA+DHA supplementation during pregnancy delayed the onset of delivery to term or closer to term; however, supplementation did not delay delivery to the point of being post-term (20, 23, 25). This supports the evidence that EPA+DHA ingestion leads to optimal pregnancy length. EPA+DHA supplementation reduced the HR of preterm delivery by 44% (95% CI: 14–64%) in those who consumed relatively low amounts of fish and 39% (95% CI: 16–56%) in those who consumed medium amounts of fish; however, a level of statistical significance was not met (P = 0.10) (23). The Judge et al. (20) study found that women who had DHA supplementation from gestation week 24 until full-term delivery carried their infants significantly (P = 0.019) longer than did the women in the placebo group. One study found that DHA supplementation after gestation week 21 led to fewer preterm births (<34 wk of gestation) in the DHA group compared with the control group (1.09% vs. 2.25%; adjusted RR, 0.49; 95% CI: 0.25–0.94; P = 0.03). Also, mean birth weight was 68 g heavier (95% CI: 23–114 g; P = 0.003) and fewer infants were of low birth weight in the DHA group compared with the control group (3.41% vs. 5.27%; adjusted RR, 0.65; 95% CI: 0.44–0.96; P = 0.03) (25).
To reach the required dose of EPA for treating certain conditions such as depression, CVD or CFS/ME you would need to take approximately 1-2 grams of ‘free EPA’ daily. Even with a concentrated omega-3 fish oil supplement, offering 180 mg excess EPA over DHA, this would require 10-20 capsules daily – significant in terms of volume and cost, and not efficient in terms of uptake in the body as our capacity for fat absorption is limited. The most effective and efficient way to ensure high EPA uptake in the body rapidly is to supplement with pure EPA for a minimum of 3-6 months.
If we want to deliver the benefits associated with EPA therapeutically, it is essential to optimise digestion and uptake. If we take EPA and DHA in their natural 1.5:1 ratio, it’s an uphill struggle for EPA because we know that DHA is more effectively absorbed and assimilated into cells. Delivering the benefits of EPA (for example, for cognitive function, mood and depression, inflammation regulation, heart health, skin health and so on), requires doses of EPA in excess of DHA, which determines the type of benefits obtained and the degree of the beneficial outcomes. The higher the ratio of EPA to DHA (meaning higher doses of EPA in relation to DHA), the more likely that EPA will be digested and absorbed, ready to meet the body’s high demands for this important nutrient.
This fact sheet by the Office of Dietary Supplements (ODS) provides information that should not take the place of medical advice. We encourage you to talk to your healthcare providers (doctor, registered dietitian, pharmacist, etc.) about your interest in, questions about, or use of dietary supplements and what may be best for your overall health. Any mention in this publication of a specific product or service, or recommendation from an organization or professional society, does not represent an endorsement by ODS of that product, service, or expert advice.
Secondary prevention fish oil studies demonstrate a significant reduction in MI. But unfortunately, both the observational and randomized trials were conducted in an era before the widespread use of HMG-CoA reductase inhibitors, and therefore, the incremental benefit is still unknown. Nevertheless, in patients receiving antiplatelet and anticoagulant therapy in addition to fish oil supplementation (even at doses as high as 4 g per day), no serious adverse complications have been reported.
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.
×