Omega-3s have been studied in various mood disorders, such as postpartum depression, with some promising results. In bipolar disorder (manic depression), the omega-3s may be most effective for the depressed phase rather than the manic phase of the illness. The omega-3s have also been proposed to alleviate or prevent other psychiatric conditions including schizophrenia, borderline personality disorder, obsessive compulsive disorder, and attention deficit disorder. However, there is still not enough evidence to recommend the omega-3s in these conditions.

Haberka, M., Mizia-Stec, K., Mizia, M., Janowska, J., Gieszczyk, K., Chmiel, A., Zahorska-Markiewicz, B., and Gasior, Z. N-3 polyunsaturated fatty acids early supplementation improves ultrasound indices of endothelial function, but not through NO inhibitors in patients with acute myocardial infarction: N-3 PUFA supplementation in acute myocardial infarction. Clin.Nutr. 2011;30(1):79-85. View abstract.


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]

Fish oil is effective in reducing inflammation in the blood and tissues. Regular consumption of fish oil supplements, tablets, pills, and capsules is helpful to those who suffer from chronic inflammatory diseases. Fish oil is effective in treating gastrointestinal disorders, Celiac disease, short bowel syndrome and inflammatory bowel disease (IBD) including Crohn’s Disease and ulcerative colitis, which are both typical disorders of the intestine. Patients suffering from Crohn’s disease often find it difficult to absorb vitamins, fats, and essential supplements. Fish oil supplements are an effective diet for such patients.
Fish oil contamination even among “molecularly distilled” brands and those aimed at children is a widespread problem. One study in California tested 10 common brands and found PCBs — toxic industrial pollutants that have contaminated our oceans — in all of them. Some had 70 times the PCBs of other ones and 240x the toxicity. In another study, researchers tested 13 over-the-counter children’s dietary supplements containing fish oil for PCBs. PCBs were detected in all products. Our family takes algae-derived omega-3 (DHA/EPA) capsules, which are bioequivalent to fish oil capsules. Algae are actually the source where fish get their omega-3 content, so we skip the contaminated middle man (or, fish, in this case) and the neurotoxins that come with them given how polluted our oceans are now. I highly recommend parents do their research on what studies show about fish oil contamination and not just trust the labels, as well as consider algae-derived omega-3 capsules as more healthful bioequivalent to fish oil.
Most Americans take in far more of another essential fat—omega-6 fats—than they do omega-3 fats. Some experts have raised the hypothesis that this higher intake of omega-6 fats could pose problems, cardiovascular and otherwise, but this has not been supported by evidence in humans. (4) In the Health Professionals Follow-up Study, for example, the ratio of omega-6 to omega-3 fats wasn’t linked with risk of heart disease because both of these were beneficial. (5) Many other studies and trials in humans also support cardiovascular benefits of omega-6 fats. Although there is no question that many Americans could benefit from increasing their intake of omega-3 fats, there is evidence that omega-6 fats also positively influence cardiovascular risk factors and reduce heart disease.
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]
Omega−3 fatty acids are formed in the chloroplasts of green leaves and algae. While seaweeds and algae are the source of omega−3 fatty acids present in fish, grass is the source of omega−3 fatty acids present in grass fed animals.[134] When cattle are taken off omega−3 fatty acid rich grass and shipped to a feedlot to be fattened on omega−3 fatty acid deficient grain, they begin losing their store of this beneficial fat. Each day that an animal spends in the feedlot, the amount of omega−3 fatty acids in its meat is diminished.[135]
A six week, double-blind study on fish oil supplementation for body composition showed that the group taking 4 grams/day of fish oil (contained 1600mg if EPA & 800mg of DHA) experienced a significant increase in lean body mass and significant decrease in fat mass compared to a group that took safflower oil (an omega-6 oil). The fish oil group also saw a tendency for decreases in cortisol, a hormone associated with belly fat gain when elevated.

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.


In later life, cognitive function and brain deterioration may become a concern. Once again, maintaining high levels of EPA has been shown to lower the risk of developing and worsening cognitive decline and dementia. If, however, you know someone who already has a diagnosis of dementia or Alzheimer’s, their brain has already been damaged and needs structural support. At this point, DHA becomes important again and taking a high-EPA product that contains 250mg of DHA also is important to prevent further loss of brain tissue.
It is well known that fish oil has the ability to improve vision. It also helps in avoiding age-related macular degeneration. The National Eye Institute at the National Institute of Health in the United States plans to conduct a nationwide study to evaluate the effect of fish oil in treating macular degeneration. This study will provide strong scientific evidence regarding the benefits of fish oil for eye care, thereby allowing government agencies and physicians to strongly recommend fish oil for macular degeneration.
for canned sardines i noticed the omega 3 EPA/DHA levels (written on the can) varied between the different company brands (sometimes by a lot!) , and also, the EPA/DHA amounts varied depending on what was added in the can with the sardines (sunflower oil, olive oil, brine, spring water, etc --- little note: there's more fat in the oily fish, than found in the brine/spring water)
ODS seeks to strengthen knowledge and understanding of dietary supplements by evaluating scientific information, supporting research, sharing research results, and educating the public. Its resources include publications (such as Dietary Supplements: What You Need to Know), fact sheets on a variety of specific supplement ingredients and products (such as vitamin D and multivitamin/mineral supplements), and the PubMed Dietary Supplement Subset
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.]
Both omega−6 and omega−3 fatty acids are essential: humans must consume them in their diet. Omega−6 and omega−3 eighteen-carbon polyunsaturated fatty acids compete for the same metabolic enzymes, thus the omega−6:omega−3 ratio of ingested fatty acids has significant influence on the ratio and rate of production of eicosanoids, a group of hormones intimately involved in the body's inflammatory and homeostatic processes, which include the prostaglandins, leukotrienes, and thromboxanes, among others. Altering this ratio can change the body's metabolic and inflammatory state.[16] In general, grass-fed animals accumulate more omega−3 than do grain-fed animals, which accumulate relatively more omega−6.[86] Metabolites of omega−6 are more inflammatory (esp. arachidonic acid) than those of omega−3. This necessitates that omega−6 and omega−3 be consumed in a balanced proportion; healthy ratios of omega−6:omega−3, according to some authors, range from 1:1 to 1:4.[87] Other authors believe that a ratio of 4:1 (4 times as much omega−6 as omega−3) is already healthy.[88][89] Studies suggest the evolutionary human diet, rich in game animals, seafood, and other sources of omega−3, may have provided such a ratio.[90][91]
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.
Mercury and polychlorinated biphenyls (PCBs) are common toxins in seafood. Although the U.S. banned the use of PCBs and DDT in 1976, these and other chemicals are still used in half the world's commercial chemical processes. Substances like these can hang around in the air, soil, and water for many years. They end up in the bodies of fish and animals.

The chemical structure of eicosapentaenoic acid and docosahexaenoic acid. Eicosapentaenoic acid consists of 20 carbons (C20) with 5 double bonds, and the last unsaturated carbon is located third from the methyl end (n-3). Do-cosahexaenoic acid consists of 22 carbons (C22) with 6 double bonds, and also with the3 last unsaturated carbon located third from the methyl end (n-3). Adapted with permission from Frishman et al, eds. Cardiovascular Pharmacotherapeutics. New York, NY: McGraw Hill; 2003.3

Scientific studies have found that fish oil can help to prevent and kill various cancers, including colon, prostate and breast. (13a) Not only has research proven that it makes conventional cancer drugs more effective, but it’s also an effective stand-alone therapy in natural cancer treatment. Intravenous fish oil lipid emulsions, in particular, are rich in omega-3 polyunsaturated fatty acids, which exhibit anti-inflammatory and immunomodulatory effects. (13b)


Weight loss. Some research shows that eating fish improves weight loss and decreases blood sugar in people who are overweight with high blood pressure. Early research also shows that taking a specific fish oil supplement (Hi-DHA, NuMega) lowers body fat when combined with exercise. But other evidence suggests that taking another specific fish oil supplement (Lovaza) does not lower body weight in overweight people.

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