Sangiovanni, J. P., Agron, E., Meleth, A. D., Reed, G. F., Sperduto, R. D., Clemons, T. E., and Chew, E. Y. {omega}-3 Long-chain polyunsaturated fatty acid intake and 12-y incidence of neovascular age-related macular degeneration and central geographic atrophy: AREDS report 30, a prospective cohort study from the Age-Related Eye Disease Study. Am J Clin Nutr 2009;90(6):1601-1607. View abstract.
Omega-3s are important components of the membranes that surround each cell in your body. DHA levels are especially high in retina (eye), brain, and sperm cells. Omega-3s also provide calories to give your body energy and have many functions in your heart, blood vessels, lungs, immune system, and endocrine system (the network of hormone-producing glands).
Wohl, D. A., Tien, H. C., Busby, M., Cunningham, C., Macintosh, B., Napravnik, S., Danan, E., Donovan, K., Hossenipour, M., and Simpson, R. J., Jr. Randomized study of the safety and efficacy of fish oil (omega-3 fatty acid) supplementation with dietary and exercise counseling for the treatment of antiretroviral therapy-associated hypertriglyceridemia. Clin.Infect.Dis. 11-15-2005;41(10):1498-1504. View abstract.
The National High Blood Pressure Education Program in the United States has cautioned against inaccurate publicity of fish oil as an effective means of lowering high blood pressure in patients suffering from hypertension. According to its report, fish oil supplements lower blood pressure in a very small way in hypertensive patients. Research conducted at the Channing Laboratory in Boston has revealed that moderate doses of fish oil supplements have little effect on the condition of high blood pressure in normotensive people.
Children: Fish oil is POSSIBLY SAFE when taken by mouth appropriately. Fish oil has been used safely through feeding tubes in infants for up to 9 months. But young children should not eat more than two ounces of fish per week. Fish oil is also POSSIBLY SAFE when given in the vein by a health care professional to infants who cannot take food by mouth. Fish oil is POSSIBLY UNSAFE when consumed from dietary sources in large amounts. Fatty fish contain toxins such as mercury. Eating contaminated fish frequently can cause brain damage, mental retardation, blindness and seizures in children.
Dornstauder, B., Suh, M., Kuny, S., Gaillard, F., MacDonald, I., Michael T. Clandinin, M. T., & Sauvé, Y. (2012, June). Dietary docosahexaenoic acid supplementation prevents age-related functional losses and A2E accumulation in the retina. Investigative Ophthalmology and Visual Science. Retrieved from http://iovs.arvojournals.org/article.aspx?articleid=2188773

Fish oils rich in omega 3 fatty acids help improve fertility and cell division. Preliminary research conducted on animals has shown that when males are fed a diet containing fish oil, the quality of the sperm is enhanced. After ejaculation, the sperm has increased survival against lipid peroxidative attacks in the female genital tract, thereby increasing the chances of conception. On the other hand, similar animal studies have shown inhibition in the synthesis of prostaglandin E and prostaglandin F, which are produced in large quantities by human seminal vesicles. The research, however, found no impact on the count and mobility of sperm.


In lab experiments, animals given krill showed improved navigation skills. What this means is that they achieved higher levels of cognition and memory required to navigate complex territory.28 In addition, research shows that animals supplemented with krill oil showed significantly fewer signs of depression and resignation. This improvement in mood was equivalent to the effect of the prescription anti-depressant drug imipramine (Tofranil®).29
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 most widely available dietary source of EPA and DHA is cold-water oily fish, such as salmon, herring, mackerel, anchovies, and sardines. Oils from these fish have a profile of around seven times as much omega-3 oils as omega-6 oils. Other oily fish, such as tuna, also contain omega-3 in somewhat lesser amounts. Although fish is a dietary source of omega-3 oils, fish do not synthesize them; they obtain them from the algae (microalgae in particular) or plankton in their diets.[22]

Could you be deficient in omega-3s? The University of Maryland Medical Center says that the symptoms “include fatigue, poor memory, dry skin, heart problems, mood swings or depression, and poor circulation.” They also warn against a poor omega-3 to omega-6 ratio, cautioning readers that it may be “associated with worsening inflammation over time.” (6)

Although results from studies regarding the disease processes of AD seem to be promising, there are conflicting data regarding the use of omega-3 fatty acids in terms of cognitive function. Neuropsychiatric symptoms accompany AD from early stages and tend to increase with the progression of the disease (55). An analysis of 174 patients randomized to a placebo group or to a group with mild to moderate AD (MMSE score ≥15) treated with daily DHA (1.7 g) and EPA (0.6 g) found that at 6 mo, the decline in cognitive function did not differ between the groups. Yet, in a subgroup with very mild cognitive dysfunction (n = 32, MMSE score >27), they observed a significant reduction in the MMSE decline rate in the DHA+EPA-supplemented group compared with the placebo group (47). Another study that looked at DHA supplementation in individuals with mild to moderate AD used the Alzheimer's Disease Assessment Scale–Cognitive subscale, which evaluates cognitive function on a 70-point scale in terms of memory, attention, language, orientation, and praxis. This study found that DHA supplementation had no beneficial effect on cognition during the 18-mo trial period for the DHA group vs. placebo (56).


Warfarin (Coumadin) is used to slow blood clotting. Fish oil also might slow blood clotting. Taking fish oil with warfarin might slow blood clotting too much and increase the risk of bleeding. However, conflicting results suggests that fish oil does not increase the effects of warfarin. Until more is known, use cautiously in combination with warfarin. Have your blood checked regularly, as your dose of warfarin (Coumadin) might need to be changed.
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.
The FDA recommends that consumers do not exceed more than three grams per day of EPA and DHA combined, with no more than 2 grams from a dietary supplement.[56] This is not the same as 3000 mg of fish oil. A 1000 mg pill typically has only 300 mg of omega-3; 10 such pills would equal 3000 mg of omega-3. According to the European Food Safety Authority's (EFSA) Panel on Dietetic Products, Nutrition and Allergies, supplementation of 5 grams of EPA and DHA combined does not pose a safety concern for adults.[57] Dyerberg studied healthy Greenland Inuit and found an average intake of 5.7 grams of omega-3 EPA per day; among other effects these people had prolonged bleeding times, i.e., slower blood clotting.[58]
Omega-3 fatty acids are found primarily in fish oil and certain marine algae. Because depression appears less common in nations where people eat large amounts of fish, scientists have investigated whether fish oils may prevent and/or treat depression and other mood disorders. Two omega-3 fatty acids — eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) — are thought to have the most potential to benefit people with mood disorders.
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.
Thanks to fatdog11 for that informative post about PCB’s in fish-oil supplements. Are these same toxicity levels found in fish themselves, or possibly are these levels so high only in highly concentrated fish-oil products? Also, can fatdog11 please inform us more about algae-derived omega-3. What are the DHA and EPA levels in these capsules? What is the cost, and where can they be purchased?

As you likely know (and as I’ve been discussing for years), omega-3 fatty acids have anti-inflammatory properties. They have been studied for the treatment and prevention of many diseases, several of which are related to inflammation, including heart disease, stroke, cancer, and Alzheimer’s disease. They have also been shown to be extraordinarily helpful in preventing and treating other brain conditions such as depression and other psychiatric disorders, attention deficit/hyperactivity disorder (ADHD), and concussions.

Bemelmans, W. J., Broer, J., Feskens, E. J., Smit, A. J., Muskiet, F. A., Lefrandt, J. D., Bom, V. J., May, J. F., and Meyboom-de Jong, B. Effect of an increased intake of alpha-linolenic acid and group nutritional education on cardiovascular risk factors: the Mediterranean Alpha-linolenic Enriched Groningen Dietary Intervention (MARGARIN) study. Am J Clin Nutr 2002;75(2):221-227. View abstract.


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 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]
Omega−3 fatty acids are important for normal metabolism.[8] Mammals are unable to synthesize omega−3 fatty acids, but can obtain the shorter-chain omega−3 fatty acid ALA (18 carbons and 3 double bonds) through diet and use it to form the more important long-chain omega−3 fatty acids, EPA (20 carbons and 5 double bonds) and then from EPA, the most crucial, DHA (22 carbons and 6 double bonds).[8] The ability to make the longer-chain omega−3 fatty acids from ALA may be impaired in aging.[9][10] In foods exposed to air, unsaturated fatty acids are vulnerable to oxidation and rancidity.[11]
The question is whether the observed cardiovascular benefits often found among fish eaters is due solely to the oils in fish or to some other characteristics of seafood or to still other factors common to those who eat lots of fish, like eating less meat or pursuing a healthier lifestyle over all. Whatever the answer, it does not seem to be fish oil supplements.
Some people who are hypersensitive to fish or have a known allergy to fish products may have a negative reaction to fatty acids which were derived from fish. Some fish oil tablets are also produced with alpha-linolenic acids which come from nuts, which may aggravate those which have an allergy to these products. In many cases these allergies will manifest themselves as a skin rash, but the symptoms could be more severe depending on the severity of your allergies. People with this concern will need to avoid using these products.
Grigg, L. E., Kay, T. W., Valentine, P. A., Larkins, R., Flower, D. J., Manolas, E. G., O'Dea, K., Sinclair, A. J., Hopper, J. L., and Hunt, D. Determinants of restenosis and lack of effect of dietary supplementation with eicosapentaenoic acid on the incidence of coronary artery restenosis after angioplasty. J Am Coll Cardiol. 3-1-1989;13(3):665-672. View abstract.

Brain function and vision rely on dietary intake of DHA to support a broad range of cell membrane properties, particularly in grey matter, which is rich in membranes.[61][62] A major structural component of the mammalian brain, DHA is the most abundant omega−3 fatty acid in the brain.[63] It is under study as a candidate essential nutrient with roles in neurodevelopment, cognition, and neurodegenerative disorders.[61]


One day I was cooking pasta when the kitchen started to fill with the odor of fish. I happen to hate fish, so this was not a pleasant experience. It was also a mystery, since I never cook fish. A little detective work discovered that the offensive odor was coming from the pasta. Apparently I didn’t notice the “Now with Omega 3” label on the box when I purchased it. My daughter and I still refer to this as the “fish pasta incident”.
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]

What are the benefits of cod liver oil? This article provides detailed information on the health benefits associated with cod liver oil, and its potential therapeutic properties. This article looks at some of the claims that cod liver oil might improve cardiovascular health, ease joint stiffness caused by arthritis, and repair wounds. Read on to learn more. Read now
Moertl, D., Hammer, A., Steiner, S., Hutuleac, R., Vonbank, K., and Berger, R. Dose-dependent effects of omega-3-polyunsaturated fatty acids on systolic left ventricular function, endothelial function, and markers of inflammation in chronic heart failure of nonischemic origin: a double-blind, placebo-controlled, 3-arm study. Am.Heart J. 2011;161(5):915-919. View abstract.

The number, location, and orientation of the double bonds determine the health effects of fatty acids on the body. One aspect of this is their effect on triglycerides and LDL and HDL types of cholesterol, which in turn affect how much cholesterol gets deposited on the inside of blood vessels. There are also subtypes of LDL and HDL which are also likely important to their health effects.
Ramakrishnan, U., Stein, A. D., Parra-Cabrera, S., Wang, M., Imhoff-Kunsch, B., Juarez-Marquez, S., Rivera, J., and Martorell, R. Effects of docosahexaenoic acid supplementation during pregnancy on gestational age and size at birth: randomized, double-blind, placebo-controlled trial in Mexico. Food Nutr Bull 2010;31(2 Suppl):S108-S116. View abstract.

Fish oil contains two very important omega-3 PUFAs. I’m talking about docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). DHA and EPA are sometimes called the marine omega-3s because they mainly come from fish. Some of the best fish to eat to obtain fish oil from in your diet include wild-caught salmon, herring, white fish, sardines and anchovies.


Good points, Miroslav. Focusing on your 4th point, with so many different formulations on the market that contain various preservatives, only looking at the blood levels of omega-3’s as the flag for increased risk for prostate cancer tends to ignore the fact that certain populations in coastal regions maintain a diet high in omega fish oils and don’t have a marked increase level of prostate cancer, pointing to the fact that another agent may be to blame here.
Cancer. Research on the effects of fish oil in preventing cancer has produced conflicting results. Some population research suggests that eating fish or having higher blood levels of omega-3 fatty acids from fish oil is linked to a lower risk of different cancers, including oral cancer, pharyngeal cancer, esophageal cancer, colon cancer, rectal cancer, breast cancer, ovarian cancer, and prostate cancer. But other research suggests that eating fish does not reduce the risk of cancer.
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