Although there are no randomized data on fish oil consumption and protection from sudden death, observational studies have linked omega-3 FA with the prevention of sudden death. In a population-based, case-control study of sudden cardiac death victims, the mean red blood cell membrane omega-3 FA level of the lowest quartile, when compared with the mean level of the third quartile, was associated with a relative risk reduction of 70%.33 A similar finding was appreciated in a nested, prospective, case-control study of the Physician Health Study cohort of 22,000 healthy males. In the 119 patients that succumbed to sudden death, baseline omega-3 FA blood levels were significantly lower than in matched controls.34 Finally, in an analysis of data from the Nurses Health Study, a cohort study of 84,688 women, an inverse association was shown between fish consumption and CAD-related death. The investigators concluded that the reduction in CAD deaths was likely due to a reduction in sudden deaths, as there was no difference in the rate of MI when comparing high and low fish consumption.35
Omega 3 is a type of fat. Small amounts of omega 3 fats are essential for good health, and they can be found in the food that we eat. The main types of omega 3 fatty acids are; alpha­linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).  ALA is normally found in fats from plant foods, such as nuts and seeds (walnuts and rapeseed are rich sources). EPA and DHA, collectively called long chain omega 3 fats, are naturally found in fatty fish, such as salmon and fish oils including cod liver oil.
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.
Research conducted by Professor Peter Howe at the University of South Australia has shown that fish oil improves the efficacy of exercise in attempts to reduce weight. Volunteers who were given fish oil in their diet showed greater weight loss as compared to those who did not regularly consume it. Fish oil contains omega-3 fatty acids, which help to promote the weight loss, so a combination of physical workout and intake of this oil helps in reducing body fat significantly faster.

People used to believe that osteoporosis and osteoarthritis were the result of aging and reduced intake of calcium and milk products. Science has now shown that these bone and joint disorders are, in part, due to inflammation. Because of this, bones and joints are prime targets for the anti-inflammatory properties of omega-3 oils from both fish and krill.

Increased EPA levels in the blood and cell membranes effectively regulates inflammatory pathways and reduces total inflammatory ‘load’, so for any inflammatory conditions or concerns, we recommend a phase of pure EPA supplementation for at least 3-6 months. Pre-loading the body with pure EPA (without the opposing actions of DHA for uptake and utilisation) ensures constant replenishment of EPA ’supplies’ to support its high rate of turnover. Since DHA levels remain fairly stable and much lower daily amounts are required, DHA levels can be supported continually through dietary intake, or increased to 250 mg daily in later stages of treatment through supplementation.

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.

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.
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.
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.
Oftentimes this could be a result of poor body composition, poor activity levels, or other things, like a low-quality diet. Now, for other people, I do think it’s the case that for people who do not eat fish and for people whose animal products, especially their eggs, are mostly from animals fed grains rather than pasture-raised animals or who don’t eat eggs, I think in those cases there is an argument for fish oil in the sense that those people are probably not going to get enough omega-3 fatty acids, but the better argument might be: Eat pastured eggs or eat fish. Even eating an oily fish like salmon once or twice a week is probably good enough to provide the omega-3 fatty acids that you need. Eating some pastured egg yolks every day is probably good enough to provide for the omega-3 fatty acids that you need.
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).
Children require DHA for growth and development, and the brain, CNS and retina rely heavily on the adequate supply of DHA during growth in the womb. Thus women should emphasise DHA in their diets when they become pregnant and continue to take this until they cease breastfeeding. Children continue to need DHA up until the age they start school, so if children under the age of five are taking an omega-3 supplement, it should contain DHA. The exception is for children with developmental problems – where pure EPA or high EPA omega-3 has been shown to be most effective for supporting cognitive function. We would still recommend, where possible, naturally derived sources of omega-3 such as oily fish to support a balanced EPA and DHA intake.
One meta-analysis concluded that omega−3 fatty acid supplementation demonstrated a modest effect for improving ADHD symptoms.[39] A Cochrane review of PUFA (not necessarily omega−3) supplementation found "there is little evidence that PUFA supplementation provides any benefit for the symptoms of ADHD in children and adolescents",[40] while a different review found "insufficient evidence to draw any conclusion about the use of PUFAs for children with specific learning disorders".[41] Another review concluded that the evidence is inconclusive for the use of omega−3 fatty acids in behavior and non-neurodegenerative neuropsychiatric disorders such as ADHD and depression.[42]
As always with such trials, you can never prove zero benefit (or zero risk), but an essentially negative trial or meta-analysis sets statistical limits on the size of any remaining plausible effect. What we can now say with a fairly high degree of confidence is that any health benefit from consuming omega-3 fatty acids is tiny, probably too small to warrant supplementing (or adding it to pasta).
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.

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
Damage to the kidneys caused the drug cyclosporine. Cyclosporine is a medication that reduces the chance of organ rejection after an organ transplant. Taking fish oil seems to prevent kidney damage in people taking this drug. Fish oil also seems to improve kidney function during the recovery phase following the rejection of a transplanted organ in people taking cyclosporine.