According to the Cardiovascular Research Institute in Maastricht in Netherlands, “Epidemiological studies show that replacing fat with carbohydrates may even be worse [than the Western-type high-fat diet] and that various polyunsaturated fatty acids (FA) have beneficial rather than detrimental effects on CVD (cardiovascular disease) outcome.” This includes fish-oil fatty acids with anti-inflammatory properties, which can help prevent and reverse a plethora of cardiovascular diseases. (19)


Anxiety, the most commonly experienced psychiatric symptom, is a psychological state derived from inappropriate or exaggerated fear leading to distress or impairment. The lifetime prevalence of any anxiety disorder is reported to be approximately 1 in 3.1 Anxiety is often comorbid with depressive disorders2 and is associated with lower health-related quality of life3 and increased risk of all-cause mortality.4 Treatment options include psychological treatments, such as cognitive-behavioral therapy and pharmacological treatments, mainly with selective serotonin reuptake inhibitors.5 Individuals with anxiety and related disorders tend to be more concerned about the potential adverse effects of pharmacological treatments (eg, sedation or drug dependence) and may be reluctant to engage in psychological treatments that can be time-consuming and costly, as well as sometimes limited in availability.6 Thus, evidence-based and safer treatments are required, especially for anxious patients with comorbid medical conditions.
Today, the average American has a 20:1 ratio of omega-6 to omega-3 fats, when a healthy ratio is more ideally around 2:1. Put in other numerical terms, the typical American diet tends to contain 14 to 25 times more omega-6 fatty acids than omega-3 fatty acids. (35) This shows just how deficient most of us are and why supplementing with fish oil is so beneficial.
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.
The effect of fish oil consumption on prostate cancer is controversial,[28][29] as one study showed decreased risk with higher blood levels of DPA, whereas another reported increased risk of more aggressive prostate cancer with higher blood levels of combined EPA and DHA.[30] Some evidence indicated an association between high blood levels of omega-3 fatty acids and an increased prostate cancer risk.[31]

There was no significant association between the Hedges g and mean age (k, 17; P = .51), female proportion (k, 18; P = .32), mean omega-3 PUFA dosage (k, 19; P = .307), EPA to DHA ratio (k, 17; P = .86), dropout rate in the omega-3 PUFA group (k, 18; P = .71), duration of omega-3 PUFA treatment (k, 19; P = .14), Jadad score of randomization (k, 19; P = .10), Jadad score of blindness (k, 19; P = .57), or total Jadad score (k, 19; P = .18).
Abnormal cholesterol or fat levels in the blood (dyslipidemia). There is conflicting evidence about the effects of fish oil on cholesterol and fat levels in the blood. Some research shows that taking fish oil can lower triglyceride levels, low density lipoprotein (LDL or "bad") cholesterol, and increase high density lipoprotein (HDL or "good") cholesterol in people with abnormal cholesterol levels. However, other research shows that taking fish oil daily does not have this effect.
Nonetheless, large population studies with solid data both on the participants’ diets and causes of disease and death bolstered the beliefs that eating fish often was a heart-healthy practice linked to reduced rates of cardiovascular disease. For example, a comprehensive analysis conducted by Dr. Dariush Mozaffarian and Eric Rimm of the Harvard T.H. Chan School of Public Health found that eating two servings of fatty fish a week — equal to about two grams of omega-3 fatty acids — lowered the risk of death from heart disease by more than a third and total deaths by 17 percent.
The FDA product label on Lovaza warns of potential bleeding complications with the coadministration of anticoagulants. This warning is based on observational studies that suggested a prolonged bleeding time in populations ingesting high levels of fish oil77 and on in vitro studies that demonstrated an effect on pro-thrombotic mediators such as a reduction in thromboxane A2 production78 and platelet activation factor.79 The same trend, however, has not been clearly demonstrated in measurements of clotting times or in factors of fibrinolysis.80 In addition, in randomized clinical trials of patients undergoing coronary artery bypass graft surgery, percutaneous transluminal coronary angioplasty, endarterectomy and diagnostic angiography, no adverse bleeding related events have been demonstrated.81 For example, in a trial of 500 patients randomized to pretreatment with 6.9 g of DHA and EPA preparation 2 weeks before balloon percutaneous transluminal coronary angioplasty (where all the patients received 325 mg/d of aspirin and heparin bolus periprocedure), no difference was seen in bleeding complications.82 Similar results were seen in a trial of 610 patients undergoing coronary artery bypass graft surgery, randomized to either placebo or 4 g/d of fish oil and then further randomized to aspirin or warfarin (dosed to an international normalized ratio [INR] goal of 2.5–4.2). At 1 year, the number of bleeding complications was not increased.15 The effect of fish oil on INR values has not been studied extensively, but a small, randomized trial showed that fish oil did not alter the Coumadin dosing regimen.83 There is very little evidence that a lower target INR is necessary in patients receiving chronic warfarin therapy and fish oil.
Omega-3 FA most likely reduce serum triglyceride levels by modulating very-low-density lipoprotein (VLDL) and chylomicron metabolism. There is a consistent finding in the literature that the end effect of fish oil is decreased hepatic secretion of VLDL17—the major endogenous source of triglycerides. This effect occurs most likely through multiple mechanisms, including: (1) decreased synthesis of triglycerides because these omega-3 FA may not be the preferred substrates of the enzyme diacylglycerol O-acyltransferase,18 or they may interact with nuclear transcription factors that control lipogenesis19; cellular metabolism consequently shifts toward a decrease in triglyceride synthesis and an increase in FA oxidation; and (2) the promotion of apolipoprotein B degradation in the liver through the stimulation of an autophagic process.20 This means that fewer VLDL particles can be assembled and secreted. Fish oil may also accelerate VLDL and chylomicron clearance21 by inducing lipoprotein lipase activity.22
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Maclean, C. H., Mojica, W. A., Morton, S. C., Pencharz, J., Hasenfeld, Garland R., Tu, W., Newberry, S. J., Jungvig, L. K., Grossman, J., Khanna, P., Rhodes, S., and Shekelle, P. 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. Evid.Rep.Technol.Assess.(Summ.) 2004;(89):1-4. View abstract.
Rondanelli, M., Giacosa, A., Opizzi, A., Pelucchi, C., La, Vecchia C., Montorfano, G., Negroni, M., Berra, B., Politi, P., and Rizzo, A. M. Effect of omega-3 fatty acids supplementation on depressive symptoms and on health-related quality of life in the treatment of elderly women with depression: a double-blind, placebo-controlled, randomized clinical trial. J.Am.Coll.Nutr. 2010;29(1):55-64. View abstract.

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)

Omega-3 [(n-3)] fatty acids have been linked to healthy aging throughout life. Recently, fish-derived omega-3 fatty acids EPA and DHA have been associated with fetal development, cardiovascular function, and Alzheimer's disease. However, because our bodies do not efficiently produce some omega-3 fatty acids from marine sources, it is necessary to obtain adequate amounts through fish and fish-oil products. Studies have shown that EPA and DHA are important for proper fetal development, including neuronal, retinal, and immune function. EPA and DHA may affect many aspects of cardiovascular function including inflammation, peripheral artery disease, major coronary events, and anticoagulation. EPA and DHA have been linked to promising results in prevention, weight management, and cognitive function in those with very mild Alzheimer's disease.
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.
Heart disease. Research suggests that eating fish can be effective for keeping people with healthy hearts free of heart disease. People who already have heart disease might also be able to lower their risk of dying from heart disease by eating fish. The picture is less clear for fish oil supplements. For people who already take heart medications such as a "statin" and those who already eat a decent amount of fish, adding on fish oil might not offer any additional benefit.
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]
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.
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.
FDA pregnancy category C. It is not known whether Fish Oil will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using Fish Oil. It is not known whether omega-3 polyunsaturated fatty acids pass into breast milk or if this could harm a nursing baby. Do not use Fish Oil without telling your doctor if you are breast-feeding a baby. Do not give this medication to anyone under 18 years old.
An analysis based on data from the Norwegian Women and Cancer Study (NOWAC) with regards to the dangers of persistent organic pollutants (POPs) in cod liver came to the conclusion that "in Norwegian women, fish liver consumption was not associated with an increased cancer risk in breast, uterus, or colon. In contrast, a decreased risk for total cancer was found."[65]
One day I was cooking pasta when the kitchen started to fill with the odor of fish. I happen to hate fish, so this was not a pleasant experience. It was also a mystery, since I never cook fish. A little detective work discovered that the offensive odor was coming from the pasta. Apparently I didn’t notice the “Now with Omega 3” label on the box when I purchased it. My daughter and I still refer to this as the “fish pasta incident”.
Consumers of oily fish should be aware of the potential presence of heavy metals and fat-soluble pollutants like PCBs and dioxins, which are known to accumulate up the food chain. After extensive review, researchers from Harvard's School of Public Health in the Journal of the American Medical Association (2006) reported that the benefits of fish intake generally far outweigh the potential risks.
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.
Humans are unable to place double bonds beyond position 9 on long chain polyunsaturated fatty acids (FA), making the omega-3 FA synthesized in plants and in marine microalgae essential elements to the human diet.1 Fish contain high levels of 2 omega-3 FA, eicosapentaenoic acid (EPA; C20:5 n-3), and docosahexaenoic acid [DHA]; C22:6 n-3)2,3 (Fig. 1). Many claims about the role of these omega-3 FA have been made in the prevention and treatment of cardiovascular disease. For instance, fish oil is seen as having a therapeutic role in coronary artery disease (CAD), heart failure, fatal and nonfatal arrhythmias, as well as offering an alternative or adjunct to the standard therapy for hypertriglyceridemia and diabetes. This review will highlight the potential mechanisms of fish oil on cardiovascular disease and provide an update of clinical trial results. The established uses in the treatment of hypertriglyceridemia and sources of omega-3 FA—both dietary and drug therapy—will be iterated, along with its potential application in combination with standard hypolipidemic agents. Finally, the limitations of current data will be addressed, as well as suggested recommendations for clinical use.
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)
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.
According to research conducted at Harvard University, omega-3 fatty acid deficiency is officially one of the top 10 causes of death in America, claiming the lives of up to 96,000 people each year. Out of the 12 dietary, lifestyle and metabolic risk factors examined in the study, omega-3 fatty acid deficiency ranked as the sixth highest killer of Americans. (1) These deaths are considered preventable since getting enough omega 3-fatty acids in your diet can ward off this now common cause of death, and fish oil benefits omega-3 intake as a potent omega-3 source.

The health benefits of fish oil can be incredible for the body’s largest organ, the skin. This source of essential fats improves the health and beauty of human skin in several ways. Fish oil benefits and nourishes the skin with fats and contributes fat-soluble vitamins that help skin maintain a smooth, elastic texture. There is also evidence that fish oil prevents wrinkles and works against the aging process.

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.


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
Omega-3 FA most likely reduce serum triglyceride levels by modulating very-low-density lipoprotein (VLDL) and chylomicron metabolism. There is a consistent finding in the literature that the end effect of fish oil is decreased hepatic secretion of VLDL17—the major endogenous source of triglycerides. This effect occurs most likely through multiple mechanisms, including: (1) decreased synthesis of triglycerides because these omega-3 FA may not be the preferred substrates of the enzyme diacylglycerol O-acyltransferase,18 or they may interact with nuclear transcription factors that control lipogenesis19; cellular metabolism consequently shifts toward a decrease in triglyceride synthesis and an increase in FA oxidation; and (2) the promotion of apolipoprotein B degradation in the liver through the stimulation of an autophagic process.20 This means that fewer VLDL particles can be assembled and secreted. Fish oil may also accelerate VLDL and chylomicron clearance21 by inducing lipoprotein lipase activity.22
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.
Gorjao, R., Verlengia, R., Lima, T. M., Soriano, F. G., Boaventura, M. F., Kanunfre, C. C., Peres, C. M., Sampaio, S. C., Otton, R., Folador, A., Martins, E. F., Curi, T. C., Portiolli, E. P., Newsholme, P., and Curi, R. Effect of docosahexaenoic acid-rich fish oil supplementation on human leukocyte function. Clin Nutr 2006;25(6):923-938. View abstract.
Typical Western diets provide ratios of between 10:1 and 30:1 (i.e., dramatically higher levels of omega−6 than omega−3).[92] The ratios of omega−6 to omega−3 fatty acids in some common vegetable oils are: canola 2:1, hemp 2–3:1,[93] soybean 7:1, olive 3–13:1, sunflower (no omega−3), flax 1:3,[94] cottonseed (almost no omega−3), peanut (no omega−3), grapeseed oil (almost no omega−3) and corn oil 46:1.[95]

My estimate is that close to 90 percent of fish oils on the market today may contain mercury and pesticide residues plus hydrogenated oils. Of course, this is my opinion based on my own research from visiting different manufacturing plants, interviewing companies, and studying the research and the listed ingredients of typical fish oils. I would stay away from ALL fish oils that do not have antioxidants like astaxanthin, which help stabilize the oil from going rancid. I always look for astaxanthin as part of any high-quality fish oil supplement.

Cast about for healthy canned tuna. Think all tuna is created equal? Think again. Choose canned light tuna instead of tuna steaks or albacore tuna. It tends to have less mercury. Albacore may contain three times the mercury of chunk light tuna. Check fish guides for the latest information about foods low in toxins but high in omega-3. Two good online sources are:

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)
Good points, Miroslav. Focusing on your 4th point, with so many different formulations on the market that contain various preservatives, only looking at the blood levels of omega-3’s as the flag for increased risk for prostate cancer tends to ignore the fact that certain populations in coastal regions maintain a diet high in omega fish oils and don’t have a marked increase level of prostate cancer, pointing to the fact that another agent may be to blame here.
To exclude the possible confounding effects of clinical variables on the Hedges g, metaregression analysis was conducted with an unrestricted maximum likelihood random-effects model of single variables when there were more than 10 data sets available. Specifically, the clinical variables of interest included mean age, female proportion, sample size, mean body mass index, daily omega-3 PUFA dosage, EPA to DHA ratio, treatment duration, dropout rate, and others. In addition, a subgroup meta-analysis was conducted to investigate potential sources of heterogeneity, specifically, a further subgroup meta-analysis focused on those trials that were placebo controlled or non–placebo controlled. To more clearly uncover the differences in the meta-analysis results among the recruited studies, a further subgroup meta-analysis was performed according to the presence of a specific clinical diagnosis or no specific clinical condition, mean omega-3 PUFA daily dosage, and mean age. In addition, in a previous study, the EPA percentage (ie, ≥60%) in the PUFA regimens had different effects on depression treatment.9 Therefore, we also arranged the subgroup meta-analysis based on the EPA percentage. Furthermore, we arranged subgroup meta-analysis procedures only when there were at least 3 data sets included.45 To investigate the potentially different estimated effect sizes between subgroups, we performed an interaction test and calculated the corresponding P values.46
Gajos, G., Zalewski, J., Rostoff, P., Nessler, J., Piwowarska, W., & Undas, A. (2011, May 26). Reduced thrombin formation and altered fibrin clot properties induced by polyunsaturated omega-3 fatty acids on top of dual antiplatelet therapy in patients undergoing percutaneous coronary intervention (OMEGA-PCI Clot). Arteriosclerosis, Thrombosis, and Vascular Biology 111.228593. Retrieved from http://atvb.ahajournals.org/content/early/2011/05/26/ATVBAHA.111.228593.abstract

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.


Jump up ^ Abdelhamid, Asmaa S; Brown, Tracey J; Brainard, Julii S; Biswas, Priti; Thorpe, Gabrielle C; Moore, Helen J; Deane, Katherine HO; AlAbdulghafoor, Fai K; Summerbell, Carolyn D; Worthington, Helen V; Song, Fujian; Hooper, Lee (18 July 2018). "Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease". Cochrane Database of Systematic Reviews. doi:10.1002/14651858.CD003177.pub3.

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.


Meta-analyses (research that combines and analyzes results of multiple studies) generally suggest that the omega-3s are effective, but the findings are not unanimous because of variability between doses, ratios of EPA to DHA, and other study design issues. The most effective preparations appear to have at least 60% EPA relative to DHA. While DHA is thought to be less effective as an antidepressant, it may have protective effects against suicide. Recent work at Massachusetts General Hospital and Emory University suggests that depressed individuals who are overweight and have elevated inflammatory activity may be particularly good candidates for EPA treatment.
Infant development. There is some evidence that mothers who eat fish or take fish oil supplements during pregnancy may improve some aspects of their baby's mental development. Taking fish oil during breast-feeding does not have this effect. However, feeding infants formula fortified with fish oil appears to improve some aspect of the baby's vision by the age of 2 months.
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