Chemical structure of alpha-linolenic acid (ALA), an essential omega−3 fatty acid, (18:3Δ9c,12c,15c, which means a chain of 18 carbons with 3 double bonds on carbons numbered 9, 12, and 15). Although chemists count from the carbonyl carbon (blue numbering), biologists count from the n (ω) carbon (red numbering). Note that, from the n end (diagram right), the first double bond appears as the third carbon-carbon bond (line segment), hence the name "n-3". This is explained by the fact that the n end is almost never changed during physiological transformations in the human body, as it is more energy-stable, and other compounds can be synthesized from the other carbonyl end, for example in glycerides, or from double bonds in the middle of the chain.

If, however, we want to target the actions and benefits of either fat for more intensive support or clinical use, we need to alter the natural 1.5:1 EPA:DHA ratio found in most omega-3 sources such as fish oil – which is when concentrated supplements are especially useful. Certain forms of omega-3 called ethyl-ester and re-esterified triglyceride give nature a helping hand – allowing us to achieve targeted ratios of specific fatty acids at high concentration and physiologically active doses.

Research conducted at the Louisiana State University has shown that fatty acids are effective in treating Alzheimer’s disease. Since fish oil is one of the best sources of essential fatty acids, including EPA and DHA, it helps in the treatment of Alzheimer’s disease. More research conducted at the University of California in Los Angeles (UCLA) validates the usefulness of fish oil as a possible remedy for the disease. The Alzheimer’s Association recommends fish containing a higher content of omega-3 fatty acids to patients since it acts as a defense against Alzheimer’s disease and dementia.

Several studies confirmed the benefit of omega-3 supplementation during pregnancy in terms of proper development of the brain and retina. Of the 2 most important long-chain omega-3 fatty acids, EPA and DHA, DHA is the more important for proper cell membrane function and is vital to the development of the fetal brain and retina (17). During the third trimester, vast amounts of DHA accumulate in fetal tissue (20). The 2 most infiltrated fetal areas include the retina and brain, which may correlate with normal eyesight and brain function (19). A study by Judge et al. (20) found that children whose mothers had taken DHA supplementation during pregnancy (n = 29) had significantly better problem-solving skills at 9 mo old (P = 0.017) than those whose mothers had not taken DHA supplementation during pregnancy (n = 15). Another study provided a cognitive assessment of children 2.5 y after maternal EPA+DHA supplementation during pregnancy from 20 wk of gestation until delivery (n = 33) compared with children in a placebo group (n = 39). Children in the EPA + DHA–supplemented group attained significantly higher scores for eye and hand coordination [mean score, 114 (SD 10.2] than those in the placebo group [mean score, 108 (SD 11.3)] (P = 0.021, adjusted P = 0.008) (19).

The Lyon Diet Heart Study, performed shortly after the DART study, was a prospective trial of 607 survivors of MI who were randomized to either a Mediterranean diet or a regular Western diet.49 At a mean follow-up of 27 months, the primary end point of death from cardiovascular causes and nonfatal deaths had a 73% relative risk reduction—a positive effect that continued at follow up assessment at a mean of 46 months.50 FA analysis of plasma lipids showed that in the patients randomized to a Mediterranean diet, there was a higher concentration of alpha-linolenic acid as well as EPA. Fish, however, was consumed in similar amounts by both the Western and Mediterranean diet groups. The higher blood level of EPA in the Mediterranean diet arm was attributed to its synthesis from alpha-linolenic acid, which was 60-times higher than the plasma concentration of EPA. In addition, the risk reduction that occurred in this trial could not be attributed to one particular diet intervention because as the consumption of fruits and vegetables increased, the consumption of monounsaturated fat increased, while saturated fat and cholesterol were decreased.
This systematic review and meta-analysis of clinical trials conducted on participants with clinical anxiety symptoms provides the first meta-analytic evidence, to our knowledge, that omega-3 PUFA treatment may be associated with anxiety reduction, which might not only be due to a potential placebo effect, but also from some associations of treatment with reduced anxiety symptoms. The beneficial anxiolytic effects of omega-3 PUFAs might be stronger in participants with specific clinical diagnoses than in those without specific clinical conditions. Larger and well-designed clinical trials should be performed with high-dose omega-3 PUFAs, provided as monotherapy and as adjunctive treatment to standard therapy.
“Lipid peroxidation induced by DHA enrichment modifies paracellular permeability in Caco-2 cells: protective role of taurine.” We conclude that hydrogen peroxide and peroxynitrite may be involved in the DHA-induced increase in paracellular permeability and that the protective role of taurine may be in part related to its capacity to counteract the effects of hydrogen peroxide.

Unintended weight loss is a problem that many patients with AD may face, and EPA+DHA supplementation has had a positive effect on weight gain in patients with AD. In a study using EPA+DHA supplementation, patients' weight significantly increased by 0.7 kg in the EPA+DHA treatment group at 6 mo (P = 0.02) and by 1.4 kg at 12 mo (P < 0.001) and was observed mainly in patients with a BMI <23 at the study start (54). This means that those patients with a lower BMI preferentially gained weight compared with those patients already with a higher BMI.

My initial interest in omga-3 was an article by Dr Andrew Stoll in Harvard about May 99, One of my bipolar patients had extreme OCD related to HIV which was not relevant to her. I put her on 9.6g of fish oil and continued her on her regular medication. She was well for the next 3 years with no obvious mental health problem when she was attending here.

It can be challenging to get the appropriate intake of EPA and DHA through diet alone, even though EPA and DHA are produced by water plants such as algae and are prevalent in marine animals. A shorter chain omega-3 fatty acid, α-linolenic acid (ALA),6 is a prominent component of our diet as it is found in many land plants that are commonly eaten, but it does not provide the health benefits seen with EPA and DHA. Although it is possible for the body to convert ALA to EPA and DHA by enlongase and desaturase enzymes, research suggests that only a small amount can be synthesized in the body from this process (8). For example, 1 study suggested that only ∼2 to 10% of ALA is converted to EPA or DHA (9), and other studies found even less: Goyens et al. (10) found an ALA conversion of ∼7% for EPA, but only 0.013% for DHA; Hussein et al. (11) found an ALA conversion of only 0.3% for EPA and <0.01% for DHA.
A March 2010 lawsuit filed by a California environmental group claimed that eight brands of fish oil supplements contained excessive levels of PCB's, including CVS/pharmacy, Nature Made, Rite Aid, GNC, Solgar, Twinlab, Now Health, Omega Protein and Pharmavite. The majority of these products were either cod liver or shark liver oils. Those participating in the lawsuit claim that because the liver is the major filtering and detoxifying organ, PCB content may be higher in liver-based oils than in fish oil produced from the processing of whole fish.[63][64]

Special attention should also be given to the fact that most women have major deficiencies of omega-3. A 1991 study at the Mayo Clinic focused on 19 "normal" pregnant women consuming "normal diets," and it showed that all were deficient in omega-3 fats. Another study compared Inuit (Eskimo) women to Canadian women, and it revealed omega-3 deficiency in the milk of the Canadian nursing moms.
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.
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.
Fish oil seems to be a subject of controversy. Some people swear by it, and there are thousands of clinical trials out now trying to study what the latest and greatest thing about the supplement is. The Natural Standard does a really good job collecting and gathering data for those who are interested in delving through what fish oil may or may not be doing to us. Definitive answers, however, may take a little while to get.
If you want to take higher doses of omega-3 fish oil supplements, talk to your doctor first. Your doctor can guide you in supplementing your diet with omega-3 fish oil. Also, your doctor can monitor all aspects of your health if you take higher doses of fish oil.For people with very high triglyceride levels, prescription omega-3 preparations are also available.

*Swordfish contains high levels of mercury, as does shark, king mackerel, and tilefish (sometimes called golden bass or golden snapper). Women who are or may become pregnant, nursing mothers, and young children should avoid these high-mercury species of fish, but can eat up to 12 ounces (two average meals) a week of a variety of fish and shellfish that are lower in mercury.

An excessive dosage of fish oil can have adverse allergies and side effects on the body. Furthermore, fish oil can be problematic if you have certain conditions so it is necessary to consume fish oil supplements cautiously. Moreover, it can be consumed in various forms. These include eating the fish directly by baking, roasting, frying, grilling, broiling, or smoking it. It can also be consumed in the form of concentrated dietary supplements like liquid, tablet, capsule, pill, or soft gels. Also, there are various pharmaceutical grades of the oil. It is not necessary to constantly consume pharmaceutical-grade oil or even supplements. You should also consult your doctor to confirm the mode of consuming fish oil and the overall need for it in 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.
Fish oils seem to help reduce some fat levels in the blood. These fats are called triglycerides. Birth control pills might decrease the effectiveness of fish oils by reducing these fat levels in the blood.Some birth control pills include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.
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.