Excessive amounts of chemicals. Using excessive amounts of fish products such as shark, farm raised salmon or mackerel can be dangerous. These products may be exposed to excessive amounts of chemicals such as mercury which can build up in the body and cause negative effects. While it is healthy to consume fish, it is important to seek out quality sources to avoid exposure to these chemicals. Using a supplement to get high levels of omega-3s into your system is also recommended because these products are produced in such a way that they will not expose you to unsafe chemicals.

Norris, J. M., Yin, X., Lamb, M. M., Barriga, K., Seifert, J., Hoffman, M., Orton, H. D., Baron, A. E., Clare-Salzler, M., Chase, H. P., Szabo, N. J., Erlich, H., Eisenbarth, G. S., and Rewers, M. Omega-3 polyunsaturated fatty acid intake and islet autoimmunity in children at increased risk for type 1 diabetes. JAMA 9-26-2007;298(12):1420-1428. View abstract.
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.

Some studies suggest that people who get higher amounts of omega-3s from foods and dietary supplements may have a lower risk of breast cancer and perhaps colorectal cancer. More research is needed to confirm this possible link. Whether omega-3s affect the risk of other cancers is not clear. Clinical trials to examine this possibility are in progress.
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 has been shown to have a direct electrophysiological effect on the myocardium. Initial experience with animal ischemia models demonstrated that the ventricular fibrillation threshold was increased in both animals fed or infused with omega-3 FA.23,24 This progressed to a demonstration, on a cellular and ion channel level, that omega-3 FA reduce both sodium currents and L-type calcium currents.25–29 It is hypothesized that during ischemia, a reduction in the sodium ion current protects hyperexcitable tissue, and a reduction in the calcium ion current reduces arrhythmogenic depolarizing currents.30
Fish oil therapy is efficacious and safe for patients with severe to moderate hypertriglyceridemia. Combination therapy with HMG-CoA reductase inhibitors is also efficacious and has not been associated with any serious adverse reactions. Fish oil therapy added to fenofibrate in patients with severe hypertriglyceridemia is also effective and safe. Accordingly, it may be a safe and effective adjunct in the pharmacotherapy of the mixed lipid disorder that is frequently encountered in patients with the metabolic syndrome and/or type II diabetes mellitus.
As a result, we depend on our diet to get the necessary Omega-3 fatty acids into our bodies. These two fatty acids work together in human health. DHA helps with cell membrane structure and assists in normal growth and development. While both EPA and DHA participate in key pathways of the immune system where they control key processes that support our health. Together they provide a number of important health benefits throughout our lifetime.
In addition to depression, chronic stress leads to loss of volume of the hippocampus—and also causes enlargement of the amygdala, the portion of the brain that regulates anxiety and anger.24 When rats were supplemented with omega-3s during exposure to stress, they showed lower corticosterone levels (a marker of stress), and improved learning on a maze—indicating that the omega-3s helped preserve memory and reduce anxiety.24
When taking fish oil, more is not always better. Remember that you want it to stay in a balanced ratio with omega-6 fats. For most people, I recommend a 1,000-milligram dose of fish oil daily as a good amount and the most scientifically studied dosage. I highly recommend not taking more than that unless directed to under the supervision of a doctor.
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
Omega-3 [(n-3)] long-chain PUFA, including EPA and DHA, are dietary fats with an array of health benefits (1). They are incorporated in many parts of the body including cell membranes (2) and play a role in antiinflammatory processes and in the viscosity of cell membranes (3, 4). EPA and DHA are essential for proper fetal development and healthy aging (5). DHA is a key component of all cell membranes and is found in abundance in the brain and retina (6). EPA and DHA are also the precursors of several metabolites that are potent lipid mediators, considered by many investigators to be beneficial in the prevention or treatment of several diseases (7).
What makes omega-3 fats special? They are an integral part of cell membranes throughout the body and affect the function of the cell receptors in these membranes. They provide the starting point for making hormones that regulate blood clotting, contraction and relaxation of artery walls, and inflammation. They also bind to receptors in cells that regulate genetic function. Likely due to these effects, omega-3 fats have been shown to help prevent heart disease and stroke, may help control lupus, eczema, and rheumatoid arthritis, and may play protective roles in cancer and other conditions.
Age-related macular degeneration (AMD) is an eye disease that can cause vision loss in older people. Two major National Institutes of Health (NIH)-sponsored studies, called Age-Related Eye Disease Study (AREDS) and Age-Related Eye Disease Study 2 (AREDS2), showed that dietary supplements containing specific combinations of vitamins, antioxidants, and zinc helped slow the progression of AMD in people who were at high risk of developing the advanced stage of this disease. AREDS2, which had more than 4,000 participants and was completed in 2013, also tested EPA and DHA. The results showed that adding these omega-3s to the supplement formulation didn’t provide any additional benefits. Other, smaller studies of omega-3 supplements also haven’t shown them to have a beneficial effect on the progression of AMD. 
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.
The benefits of omega-3 fatty acids (EPA and DHA), which are found in fish oil, have been supported by repeated double-blind clinical trials. In 2004, the FDA announced qualified health claims for omega-3 fatty acids, noting supportive but not conclusive research that shows that consuming EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease. Our Fish Oil includes 200mg of omega-3 fatty acids from EPA and DHA.
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:
In my opinion, the key benefit of DHA lies in its unique spatial characteristics. As mentioned earlier, the extra double bond (six in DHA vs. five in EPA) and increased carbon length (22 carbons in DHA vs. 20 in EPA) means that DHA takes up takes up a lot more space than does EPA in the membrane. Although this increase in spatial volume makes DHA a poor substrate for phospholipase A2 as well as the COX and LOX enzymes, it does a great job of making membranes (especially those in the brain) a lot more fluid as the DHA sweeps out a much greater volume in the membrane than does EPA. This increase in membrane fluidity is critical for synaptic vesicles and the retina of the eye as it allows receptors to rotate more effectively thus increasing the transmission of signals from the surface of the membrane to the interior of the nerve cells. This is why DHA is a critical component of these highly fluid portions of the nerves (7). On the other hand, the myelin membrane is essentially an insulator so that relatively little DHA is found in that part of the membrane.
Fish or seafood allergy: Some people who are allergic to seafood such as fish might also be allergic to fish oil supplements. There is no reliable information showing how likely people with seafood allergy are to have an allergic reaction to fish oil. Until more is known, advise patients allergic to seafood to avoid or use fish oil supplements cautiously.
Bo and I worked with Dr. Harris many years ago to measure the impact of eating one Omega Cookie® daily on the study participants’ omega-3 index levels, and we recently ran into him at ISFFAL. At the conference, we remeasured our omega-3 index and omega-6/omega-3 ratios, and a few weeks later, we got our results in the mail. For the two of us, it was exciting to get another concrete measure of how our daily omega-3 consumption impacted our scores. For the record, we take one vial of Omega Restore™ per night and frequently sneak an Omega Heaven® or Omega Cookie during the day.
Today, some doctors are starting to measure the omega-3 index levels of their patients, just like they do with cholesterol levels. However, if your doctor does not offer this, several companies provide a quick and easy blood test you can conduct yourself, including OmegaQuant. This company is run by by Dr. William Harris, one of the scientists who initially developed the concept of the omega-3 index.

High levels of the oils in blood samples were linked with a 71 per cent increased risk of developing an aggressive and dangerous form of prostate cancer, according to the research. That study, if I recall correctly, mentioned concern about men eating fish more than a certain number of times a week having a 54% increased risk of developing prostate cancer.
Brussels sprouts are a cruciferous vegetable bursting with vitamin K, vitamin C, and a healthy dose of omega-3 fatty acids. With their strong flavor and smell, however, they’re not always loved (or even tolerated) by children or adults with ADHD. If someone in your house considers sprouts the enemy, try this recipe — honey, cranberries, and parmesan cheese give these Brussels sprouts a sweet and savory flavor that even picky eaters love.
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.
Participants treated with a daily dose of 2000 mg or more of omega-3 PUFAs showed a significantly greater association of treatment with reduced anxiety symptoms. In addition, participants receiving supplements containing less than 60% EPA showed a significant association, but not those receiving supplements containing 60% or more EPA. The depression literature supports the clinical benefits of EPA-enriched formulations (≥60% or ≥50%) compared with placebo for the treatment of clinical depression.9,13,73-75 This opposite effect of EPA-enriched formations on anxiety and depression is intriguing and possibly linked to a distinct underlying mechanism of omega-3 PUFAs. Exploration of the effects of omega-3 PUFAs on anxiety symptoms is just beginning and studies assessing the dose response anxiolytic effects of omega-3 PUFAs have not yet been performed. Further phase 2 trials of anxiety symptoms among participants with neuropsychiatric illness or physical illness should aim to determine the optimal dose.
Agency for Healthcare Research and Quality. 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. AHRQ Publication No. 04-E012-1; 2004. Available at: https://archive.ahrq.gov/downloads/pub/evidence/pdf/o3lipid/o3lipid.pdf. (Accessed February 7, 2017).
Pregnancy and breast-feeding: Fish oil is LIKELY SAFE when taken by mouth appropriately. Taking fish oil during pregnancy does not seem to affect the fetus or baby while breast-feeding. Women who are pregnant or who may become pregnant, and nursing mothers should avoid shark, swordfish, king mackerel, and tilefish (also called golden bass or golden snapper), as these may contain high levels of mercury. Limit consumption of other fish to 12 ounces/week (about 3 to 4 servings/week). Fish oil is POSSIBLY UNSAFE when dietary sources are consumed in large amounts. Fatty fish contain toxins such as mercury.