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
Full citation: Abdelhamid AS, Brown TJ, Brainard JS, Biswas P, Thorpe GC, Moore HJ, Deane KHO, AlAbdulghafoor FK, Summerbell CD, Worthington HV, Song F, Hooper L. Omega 3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews 2018, Issue 7. Art. No.: CD003177. DOI: 10.1002/14651858.CD003177.pub3.

56. Davidson MH, Stein EA, Bays HE, et al. COMBination of prescription Omega-3 with Simvastatin (COMBOS) Investigators. Efficacy and tolerability of adding prescription omega-3 fatty acids 4 g/d to simvastatin 40 mg/d in hypertriglyceridemic patients: an 8-week, randomized, double-blind, placebo-controlled study. Clin Ther. 2007;29:1354–1367. [PubMed]
Studies have also found that omega-3 fatty acids from fish oil are associated with improved survival rates for heart attack victims. A study published in the medical journal Circulation found that people who took a high dose of fish oil each for six months following the occurrence of a heart attack actually improved their hearts’ overall functioning and also reduced biomarkers of systemic inflammation. (20)
Not surprising, there are some areas in which both EPA and DHA appear to be equally beneficial. As an example, both are equally effective in reducing triglyceride levels (10). This is probably due to the relatively equivalent activation of the gene transcription factor (PPAR alpha) that causes the enhanced synthesis of the enzymes that oxidize fats in lipoprotein particles. There is also apparently equal activation of the anti-inflammatory gene transcription factor PPAR-gamma (11). Both seem to be equally effective in making powerful anti-inflammatory eicosanoids known as resolvins (12). Finally, although both have no effect on total cholesterol levels, DHA can increase the size of LDL particle to a greater extent than can EPA (10).
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.
Mozaffarian D, Marchioli R, Macchia A, Silletta MG, Ferrazzi P, Gardner TJ, Latini R, Libby P, Lombardi F, O'Gara PT, Page RL, Tavazzi L, Tognoni G; OPERA Investigators. Fish oil and postoperative atrial fibrillation: the Omega-3 Fatty Acids for Prevention of Post-operative Atrial Fibrillation (OPERA) randomized trial. JAMA 2012;308(19):2001-11. View abstract.
Giacco, R., Cuomo, V., Vessby, B., Uusitupa, M., Hermansen, K., Meyer, B. J., Riccardi, G., and Rivellese, A. A. Fish oil, insulin sensitivity, insulin secretion and glucose tolerance in healthy people: is there any effect of fish oil supplementation in relation to the type of background diet and habitual dietary intake of n-6 and n-3 fatty acids? Nutr.Metab Cardiovasc.Dis. 2007;17(8):572-580. View abstract.

Krauss-Etschmann et al. (26) Double-blind, placebo-controlled, randomized 311 DHA+EPA daily with either fish oil with DHA (0.5 g) and EPA (0.15 g) or with methyltetrahydrofolic acid (400 μg), both, or placebo, from gestation week 22 Fish-oil supplementation was associated with decreased levels of maternal inflammatory/TH1 cytokines and a decrease of fetal Th2-related cytokines


Many people focus on the dosage of fish oil to take, like 1000 mg or 1200 mg, but it is the omega-3s that matter. This is where the benefits of fish oil are found. The two types of omega-3 fatty acids to focus on are EPA and DHA. These omega-3s are naturally found in oily fish like salmon, halibut, sardines and anchovies, and are the very reason why fish oil supplements have received such high praise.

Humans can convert short-chain omega−3 fatty acids to long-chain forms (EPA, DHA) with an efficiency below 5%.[73][74] The omega−3 conversion efficiency is greater in women than in men, but less studied.[75] Higher ALA and DHA values found in plasma phospholipids of women may be due to the higher activity of desaturases, especially that of delta-6-desaturase.[76]

Heterogeneity was examined using the Q statistic and the corresponding P values,41 and the I2 statistic was used to evaluate the proportion of variation resulting from among-study differences. Any possible publication bias was detected with both funnel plots and Egger regression in the main part of the meta-analysis.42 By using Duval and Tweedie’s trim-and-fill test, we adjusted the effect sizes for potential publication bias if there was evidence of publication bias detected by this test in the Comprehensive Meta-analysis statistical software, version 3.43 To investigate the potential confounding effects of any outliers within the recruited studies, sensitivity testing was conducted with the 1-study removal method to detect the potential outliers.44
The Federal Government’s Dietary Guidelines for Americans 2015–2020 recommends that adults eat 8 or more ounces of a variety of seafood (fish or shellfish) per week for the total package of nutrients seafood provides, and that some seafood choices with higher amounts of EPA and DHA be included. Smaller amounts of seafood are recommended for young children.
Sorgi, P. J., Hallowell, E. M., Hutchins, H. L. & Sears, B. (2007, January 17). Effects of an open-label pilot study with high-dose EPA/DHA concentrates on plasma phospholipids and behavior in children with attention deficit hyperactivity disorder. Nutrition Journal 6(16). Retrieved from http://nutritionj.biomedcentral.com/articles/10.1186/1475-2891-6-16
^ Jump up to: a b MacLean CH, Newberry SJ, Mojica WA, Khanna P, Issa AM, Suttorp MJ, Lim YW, Traina SB, Hilton L, Garland R, Morton SC (2006-01-25). "Effects of omega−3 fatty acids on cancer risk: a systematic review". JAMA: The Journal of the American Medical Association. 295 (4): 403–15. doi:10.1001/jama.295.4.403. PMID 16434631. Retrieved 2006-07-07.
Cardiovascular disease is the cause of 38% of all deaths in the United States, many of which are preventable (28). Chronic inflammation is thought to be the cause of many chronic diseases, including cardiovascular disease (29). EPA and DHA are thought to have antiinflammatory effects and a role in oxidative stress (30) and to improve cellular function through changes in gene expression (31). In a study that used human blood samples, EPA+DHA intake changed the expression of 1040 genes and resulted in a decreased expression of genes involved in inflammatory and atherogenesis-related pathways, such as nuclear transcription factor κB signaling, eicosanoid synthesis, scavenger receptor activity, adipogenesis, and hypoxia signaling (31). Circulating markers of inflammation, such as C-reactive protein (CRP), TNF α, and some ILs (IL-6, IL-1), correlate with an increased probability of experiencing a cardiovascular event (32). Inflammatory markers such as IL-6 trigger CRP to be synthesized by the liver, and elevated levels of CRP are associated with an increased risk of the development of cardiovascular disease (33). A study of 89 patients showed that those treated with EPA+DHA had a significant reduction in high-sensitivity CRP (66.7%, P < 0.01) (33). The same study also showed a significant reduction in heat shock protein 27 antibody titers (57.69%, P < 0.05), which have been shown to be overexpressed in heart muscle cells after a return of blood flow after a period of ischemia (ischemia-reperfusion injury) and may potentially have a cardioprotective effect (33).
Fearon, K. C., Von Meyenfeldt, M. F., Moses, A. G., Van Geenen, R., Roy, A., Gouma, D. J., Giacosa, A., Van Gossum, A., Bauer, J., Barber, M. D., Aaronson, N. K., Voss, A. C., and Tisdale, M. J. Effect of a protein and energy dense n-3 fatty acid enriched oral supplement on loss of weight and lean tissue in cancer cachexia: a randomised double blind trial. Gut 2003;52(10):1479-1486. View abstract.
Because patients with depression experience rapid shrinking of their hippocampus, many strategies for relieving depression focus on increasing new brain cell growth in that specific area of the brain.23 There’s now evidence that increasing omega-3 intake, especially DHA, may be an effective way of treating or preventing depression, partly by protecting the hippocampus from further shrinkage.23

When it comes to omega-3 benefits, there are rarely nutrients that pack this many positive health outcomes into one compound. The most commonly known benefit of omega-3s is a reduced risk of heart disease, but that’s not the only studied plus of getting lots of omega-3s in your diet — from fetal development to retinal function to weight management (and a lot more in between), these acids support and promote optimal health for anyone. (1)


AMA Manual of Style Art and Images in Psychiatry Breast Cancer Screening Guidelines Colorectal Screening Guidelines Declaration of Helsinki Depression Screening Guidelines Evidence-Based Medicine: An Oral History Fishbein Fellowship Genomics and Precision Health Health Disparities Hypertension Guidelines JAMA Network Audio JAMA Network Conferences Med Men Medical Education Opioid Management Guidelines Peer Review Congress Research Ethics Sepsis and Septic Shock Statins and Dyslipidemia Topics and Collections

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.


Omega-3s are generally safe and well tolerated. Stomach upset and “fishy taste” have been the most common complaints, but they are less frequent now thanks to manufacturing methods that reduce impurities. Past concerns about omega-3s increasing the risk of bleeding have been largely disproven, but caution is still advised in people taking blood thinners or who are about to undergo surgery. As mentioned, caution is needed in people with bipolar disorder to prevent cycling to mania. Because omega-3s are important to brain development, and pregnancy depletes omega-3 in expectant mothers, supplementation should theoretically benefit pregnant women and their children. Fish consumption in pregnancy is supported by the FDA, but because we do not have long-term data on safety or optimal dosing of omega-3s in pregnancy, expectant mothers should consider omega-3 supplements judiciously.
16. Saito Y, Yokoyama M, Origasa H, Matsuzaki M, Matsuzawa Y, Ishikawa Y, Oikawa S, Sasaki J, Hishida H, Itakura H, et al. Effects of EPA on coronary artery disease in hypercholesterolemic patients with multiple risk factors: sub-analysis of primary prevention cases from the Japan EPA Lipid Intervention Study (JELIS). Atherosclerosis. 2008;200:135–40. [PubMed]
Augood, C., Chakravarthy, U., Young, I., Vioque, J., de Jong, P. T., Bentham, G., Rahu, M., Seland, J., Soubrane, G., Tomazzoli, L., Topouzis, F., Vingerling, J. R., and Fletcher, A. E. Oily fish consumption, dietary docosahexaenoic acid and eicosapentaenoic acid intakes, and associations with neovascular age-related macular degeneration. Am J Clin Nutr 2008;88(2):398-406. View abstract.
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.

The systematic review suggests that eating more ALA through food or supplements probably has little or no effect on cardiovascular deaths or deaths from any cause. However, eating more ALA probably reduces the risk of heart irregularities from 3.3 to 2.6%. The review team found that reductions in cardiovascular events with ALA were so small that about 1000 people would need to increase consumption of ALA for one of them to benefit. Similar results were found for cardiovascular death. They did not find enough data from the studies to be able to measure the risk of bleeding or blood clots from using ALA.
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.
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.
“This systematic review did find moderate evidence that ALA, found in plant oils (such as rapeseed or canola oil) and nuts (particularly walnuts) may be slightly protective of some diseases of the heart and circulation. However, the effect is very small, 143 people would need to increase their ALA intake to prevent one person developing arrhythmia. One thousand people would need to increase their ALA intake to prevent one person dying of coronary heart disease or experiencing a cardiovascular event.  ALA is an essential fatty acid, an important part of a balanced diet, and increasing intakes may be slightly beneficial for prevention or treatment of cardiovascular disease."
Full citation: Abdelhamid AS, Brown TJ, Brainard JS, Biswas P, Thorpe GC, Moore HJ, Deane KHO, AlAbdulghafoor FK, Summerbell CD, Worthington HV, Song F, Hooper L. Omega 3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews 2018, Issue 7. Art. No.: CD003177. DOI: 10.1002/14651858.CD003177.pub3.
What about blood clotting? Circulating cells called platelets are critical in causing your blood to clot. When platelets are activated, they aggregate and cause clots. If these clots occur in particularly sensitive regions of your body, they can lead to a heart attack or stroke. EPA reduces platelet activation, an early step in platelet aggregation to help to reduce clotting. One study found that EPA was superior to DHA in decreasing platelet activation, a precursor to blood clotting.1
One of the most well-known benefits of omega-3s are the way they positively affect risk factors associated with heart disease. That’s one reason the American Heart Association is very clear about encouraging people to get enough in their diets. (8) Heart disease and stroke are the leading causes of death worldwide, but communities who eat diets rich in fish have remarkably low instances of these diseases, which is at least partially due to their high omega-3 consumption. (9, 10)

Even healthy oils form trans fats when heated. Each oil has a different temperature at which it forms its own trans fats. Generally, when the oil begins to smoke is when trans fats are formed. Did this study consider how and at what temperatures the fish were cooked? Are some of the suppliments heated before being made into capsules? Did it also consider that many types of fish have dangerous levels of mercury?
It’s uncertain whether omega-3 fatty acid supplements are helpful for depression. Although some studies have had promising results, a 2015 evaluation of 26 studies that included more than 1,400 people concluded that if there is an effect, it may be too small to be meaningful. Other analyses have suggested that if omega-3s do have an effect, EPA may be more beneficial than DHA and that omega-3s may best be used in addition to antidepressant medication rather than in place of it. 
Several other analyses of the evidence have been done in the last few years (2012 or later), and like the 2018 analysis and the AHRQ report, most found little or no evidence for a protective effect of omega-3 supplements against heart disease. However, some earlier analyses suggested that omega-3s could be helpful. The difference between the newer conclusions and the older ones may reflect two changes over time: 
Only fish and breast milk contain all the members of the omega-3 family, including its two main stars, EPA and DHA. Because Americans as a rule consume far too few omega-3s from fish or fish oil, it’s no surprise that the majority of Americans have low omega-3 index levels as well. A recent study of global omega-3 index levels found that an estimated 95% of Americans (with the exception of folks from Alaska) had an omega-3 index of 4 or below, putting them in the high risk category (5, 6, 7).

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]
EPA is the precursor to DHA in the body and can be converted to DHA with the enzyme delta-6 desaturase, but this process is inefficient in many people (much like the inefficiency of short-chain omega-3s to long-chain). For those individuals taking pure EPA products as well as those taking our EPA-rich products, we still recommend eating oily fish at least once each week to provide a natural source of DHA. Fish provides a unique nutritional package, supplying the diet with important amino acids (the building blocks of proteins) and antioxidants, including vitamins and minerals needed to process fats, so eating fish will also support the natural enzyme-dependent EPA to DHA conversion.

Ozaydin, M., Erdogan, D., Tayyar, S., Uysal, B. A., Dogan, A., Icli, A., Ozkan, E., Varol, E., Turker, Y., and Arslan, A. N-3 polyunsaturated fatty acids administration does not reduce the recurrence rates of atrial fibrillation and inflammation after electrical cardioversion: a prospective randomized study. Anadolu.Kardiyol.Derg. 2011;11(4):305-309. View abstract.

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