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.‡
The most widely available dietary source of EPA and DHA is oily fish, such as salmon, herring, mackerel, anchovies, menhaden, and sardines. Oils from these fish have a profile of around seven times as much omega−3 as omega−6. Other oily fish, such as tuna, also contain n-3 in somewhat lesser amounts. 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) [110] reported that the benefits of fish intake generally far outweigh the potential risks. Although fish are a dietary source of omega−3 fatty acids, fish do not synthesize them; they obtain them from the algae (microalgae in particular) or plankton in their diets.[111] In the case of farmed fish, omega-3 fatty acids is provided by fish oil; In 2009, 81% of the global fish oil production is used by aquaculture.[112]

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.

“This systematic review did find moderate evidence that ALA, found in plant oils (such as rapeseed or canola oil) and nuts (particularly walnuts) may be slightly protective of some diseases of the heart and circulation. However, the effect is very small, 143 people would need to increase their ALA intake to prevent one person developing arrhythmia. One thousand people would need to increase their ALA intake to prevent one person dying of coronary heart disease or experiencing a cardiovascular event.  ALA is an essential fatty acid, an important part of a balanced diet, and increasing intakes may be slightly beneficial for prevention or treatment of cardiovascular disease."
Stiefel, P., Ruiz-Gutierrez, V., Gajon, E., Acosta, D., Garcia-Donas, M. A., Madrazo, J., Villar, J., and Carneado, J. Sodium transport kinetics, cell membrane lipid composition, neural conduction and metabolic control in type 1 diabetic patients. Changes after a low-dose n-3 fatty acid dietary intervention. Ann Nutr Metab 1999;43(2):113-120. View abstract.
What's more, ALA is just a precursor to EPA and DHA. You need certain enzymes to elongate and desaturate ALA so it can become long-chained omega-3s. Unfortunately, this does not work in some people, particularly those who are deficient in certain vitamins and minerals, leading to very low conversion rates – only 1 percent of ALA is converted to EPA/DHA. In some, the conversion can even dip as low as 0.1 to 0.5 percent!

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.
The supplements contain omega-3 fatty acids, the polyunsaturated oils prominent in fatty cold water fish like salmon, sardines and mackerel. In many observational studies, people who regularly consumed fish two or more times a week were less likely to suffer heart attacks, strokes and cardiovascular deaths than those who ate fish infrequently or not at all.
Sekikawa, A., Curb, D., Ueshima, H., El-Saed, A., Kadowaki, T., Abbott, R. D., ... Kuller, L. H. (2008 August 5). Marine-derived n-3 fatty acids and atherosclerosis in Japanese, Japanese Americans, and Whites: a cross-sectional study. Journal of the American College of Cardiology 52(6), 417–424. Retrieved from
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)
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
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.
1. Omega-3 benefits your heart health. An Italian study (GISSI)5 of 11,324 heart attack survivors found that patients supplementing with fish oils markedly reduced their risk of another heart attack, stroke, or death. In a separate study, 6 American medical researchers reported that men who consumed fish once or more every week had a 50 percent lower risk of dying from a sudden cardiac event than do men who eat fish less than once a month.
We hypothesized that omega-3 PUFAs might have anxiolytic effects in patients with significant anxiety- and fear-related symptoms. However, there have been no systematic reviews of this topic to date. Thus, we examined the anxiolytic effects of omega-3 PUFAs in participants with elevated anxiety symptoms in the results of clinical trials to determine the overall efficacy of omega-3 PUFAs for anxiety symptoms irrespective of diagnosis.

Krauss-Etschmann, S., Hartl, D., Rzehak, P., Heinrich, J., Shadid, R., Del, Carmen Ramirez-Tortosa, Campoy, C., Pardillo, S., Schendel, D. J., Decsi, T., Demmelmair, H., and Koletzko, B. V. Decreased cord blood IL-4, IL-13, and CCR4 and increased TGF-beta levels after fish oil supplementation of pregnant women. J.Allergy Clin.Immunol. 2008;121(2):464-470. View abstract.
Macchia, A., Levantesi, G., Franzosi, M. G., Geraci, E., Maggioni, A. P., Marfisi, R., Nicolosi, G. L., Schweiger, C., Tavazzi, L., Tognoni, G., Valagussa, F., and Marchioli, R. Left ventricular systolic dysfunction, total mortality, and sudden death in patients with myocardial infarction treated with n-3 polyunsaturated fatty acids. Eur.J.Heart Fail. 2005;7(5):904-909. View abstract.
Respected health care organizations proposed intake recommendations for oily fish of two servings per week for healthy adults, which equates to approximately a daily total of 500 milligrams (mg) EPA and DHA.‡ The recommendation encourages adults already with or at-risk of developing cardiovascular disease to talk to their primary healthcare professional about supplementing with amounts greater than 500 mg of EPA and DHA per day. Supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease.
Other suspected health benefits of omega-3s and fish are less well established and need further study. They include suggestions of a reduced risk of breast cancer, colorectal cancer and possibly advanced prostate cancer, all related to eating fish rather than taking supplements. Some observational studies have associated omega-3s to a lower risk of cognitive decline, Alzheimer’s disease and dementia, as well as age-related macular degeneration.

As mentioned above, the omega-3 index has been suggested as a predictor of the risk of coronary heart disease and other cardiovascular events. One study on a population in Seattle found that people with low omega-3 index levels were 10 times as likely to die from sudden cardiac death compared to people with higher omega-3 index levels (13). The NIH-funded Framingham study referenced above showed that the people with the highest omega-3 index levels had a 33% reduction in risk of death from any cause compared to the people with the lowest levels (2). In addition, a new study focused on individuals age 25 to 41 found that higher omega-3 index levels were associated with lower blood pressure in healthy adults (14).

The Japanese notably have the lowest levels of coronary heart disease mortality and atherosclerosis among developed nations — a phenomena that has been largely subscribed to diet. However, even within Japan, a 10-year study of over 41,000 people found that higher intakes of omega-3s were associated with lower risks of nonfatal coronary events (8). A more recent study also found that Japanese with higher omega-3 index levels (10%) had a lower risk of fatal coronary heart disease than those with a lower omega-3 index levels (8%) (9). The study begs the question of whether maybe even the Japanese have room to improve their omega-3 intake and whether 8% should be considered the lower limit of a desirable range.
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.