I now suspect that those thousands of gel-covered capsules I’ve swallowed over the years may have done little more than enrich the pockets of supplement producers and sellers. A number of extensive analyses have been conducted, some supporting and others refuting the value of fish oils to the cardiovascular system, along with studies of other purported health benefits that also have had mixed results.
2. Omega-3 normalizes and regulates your cholesterol triglyceride levels. Compared to a statin, both fish oil and krill oil are more efficient in doing this. According to a study comparing the efficiency of krill and fish oils in reducing triglyceride levels,7 both oils notably reduced the enzyme activity that causes the liver to metabolize fat, but krill had a more pronounced effects, reducing liver triglycerides significantly more.
The US National Institutes of Health lists three conditions for which fish oil and other omega-3 sources are most highly recommended: hypertriglyceridemia (high triglyceride level), preventing secondary cardiovascular disease, and hypertension (high blood pressure). It then lists 27 other conditions for which there is less evidence. It also lists possible safety concerns: "Intake of 3 grams per day or greater of omega-3 fatty acids may increase the risk of bleeding, although there is little evidence of significant bleeding risk at lower doses. Very large intakes of fish oil/omega-3 fatty acids may increase the risk of hemorrhagic (bleeding) stroke."[12]
Dry eye. Some clinical research shows that eating more fish oil is linked to a lower risk of getting dry eye syndrome in women. Other research shows that taking a specific fish oil product (PRN Dry Eye Omega Benefits softgels) daily modestly improves symptoms of dry eye such as pain, blurred vision, and sensitivity. Other research using other forms of fish oil products suggests that taking these supplements for 4-12 weeks modest improves some dry eye symptoms. However, the sensation of eye dryness is not always improved. Other research also shows that taking a specific combination products containing fish oil and other ingredients might improve some dry eye symptoms; however, this research is conflicted and poor quality.
Kremer, J. M., Lawrence, D. A., Petrillo, G. F., Litts, L. L., Mullaly, P. M., Rynes, R. I., Stocker, R. P., Parhami, N., Greenstein, N. S., Fuchs, B. R., and . Effects of high-dose fish oil on rheumatoid arthritis after stopping nonsteroidal antiinflammatory drugs. Clinical and immune correlates. Arthritis Rheum. 1995;38(8):1107-1114. View abstract.
Your retina contains quite a bit of DHA, making it necessary for that fatty acid to function. (90) The National Eye Institute, part of the National Institutes of Health, concludes that there is “consistent evidence” suggesting long-chain polyunsaturated fatty acids DHA and EPA are necessary for retinal health and may help protect the eyes from disease. (91)
After a large number of lab studies found that omega-3 fatty acids may be effective in slowing or reversing the growth of hormonal cancers, namely prostate and breast cancer cells, animal and human epidemiological studies have been conducted to see whether this effect occurred in real-life scenarios. The evidence is somewhat conflicting in some reports, but there is some evidence to suggest breast and prostate cancers may be potentially slowed (or the risk reduced) in people who eat a lot of oily fish and possibly those who supplement with omega-3. (66, 67, 68)
The omega-3 index is also important because it is inversely related to one’s omega-6 to omega-3 ratio — another important measurement (3). A lower omega-6/omega-3 ratio (meaning, you consume a balanced amount of these two fatty acid families) is associated with a reduced risk of many chronic diseases, including cardiovascular disease, cancer, and autoimmune disease, to name a few (4). Of course, most people get far too much omega-6 and too little omega-3, thanks to the plethora of highly processed foods in the Western diet.
Jump up ^ Burch, Ernest S. (2006). Social Life in Northwest Alaska: The Structure of Iñupiaq Eskimo Nations. University of Alaska Press. p. 278. ISBN 9781889963921. Retrieved 2014-10-23. Oil was also used externally as an ointment to heal cold sores, cuts, insect bites, frostbite, rashes - in short, skin problems of all kinds. Duck or goose body-cavity fat was apparently as useful as seal or fish oil in dealing with skin problems.

Most brands of fish oil have been proven safe, free of detectable traces of mercury, and do not contain unsafe levels of PCBs (polychlorinated biphenyls), a toxin and pollutant believed to pose various health threats. To avoid contaminants in an unrefined supplement, it's best to choose a fish-oil supplement made from small, oily fish like anchovy, sardines or menhaden.
Weimann, A., Bastian, L., Bischoff, W. E., Grotz, M., Hansel, M., Lotz, J., Trautwein, C., Tusch, G., Schlitt, H. J., and Regel, G. Influence of arginine, omega-3 fatty acids and nucleotide-supplemented enteral support on systemic inflammatory response syndrome and multiple organ failure in patients after severe trauma. Nutrition 1998;14(2):165-172. View abstract.
For slowing weight loss in patients with cancer: 30 mL of a specific fish oil product (ACO Omega-3, Pharmacia, Stockholm, Sweden) providing 4.9 grams of EPA and 3.2 grams of DHA daily for 4 weeks has been used. 7.5 grams of fish oil daily providing EPA 4.7 grams and DHA 2.8 grams has been used for about 6 weeks. In addition, two cans of a fish oil nutritional supplement containing 1.09 grams of EPA and 0.96 grams of DHA per can have been used daily for up to 7 weeks.
Studies have also shown that omega-3 fats are anti-arrhythmic (preventing or counteracting cardiac arrhythmia), anti-thrombotic (prevents thrombosis or a blood clot within a blood vessel), anti-atherosclerotic (preventing fatty deposits and fibrosis of the inner layer of your arteries), and anti-inflammatory (counteracting inflammation – the heat, pain, swelling, etc).
• Fish oil – Fish oil is among the primary ways that people enhance their intake of omega-3 fats. High-quality fish oils can certainly provide many health benefits. However, this oil is weak in antioxidants. This means that as you increase your omega-3 intake through fish oil consumption, you actually increase your need for added antioxidant protection.
Omega-3 FA most likely reduce serum triglyceride levels by modulating very-low-density lipoprotein (VLDL) and chylomicron metabolism. There is a consistent finding in the literature that the end effect of fish oil is decreased hepatic secretion of VLDL17—the major endogenous source of triglycerides. This effect occurs most likely through multiple mechanisms, including: (1) decreased synthesis of triglycerides because these omega-3 FA may not be the preferred substrates of the enzyme diacylglycerol O-acyltransferase,18 or they may interact with nuclear transcription factors that control lipogenesis19; cellular metabolism consequently shifts toward a decrease in triglyceride synthesis and an increase in FA oxidation; and (2) the promotion of apolipoprotein B degradation in the liver through the stimulation of an autophagic process.20 This means that fewer VLDL particles can be assembled and secreted. Fish oil may also accelerate VLDL and chylomicron clearance21 by inducing lipoprotein lipase activity.22
High blood pressure. Fish oil seems to slightly lower blood pressure in people with moderate to very high blood pressure. Some types of fish oil might also reduce blood pressure in people with slightly high blood pressure, but results are inconsistent. Fish oil seems to add to the effects of some, but not all, blood pressure-lowering medications. However, it doesn't seem to reduce blood pressure in people with uncontrolled blood pressure who are already taking blood pressure-lowering medications.