Bergmann, R. L., Haschke-Becher, E., Klassen-Wigger, P., Bergmann, K. E., Richter, R., Dudenhausen, J. W., Grathwohl, D., and Haschke, F. Supplementation with 200 mg/day docosahexaenoic acid from mid-pregnancy through lactation improves the docosahexaenoic acid status of mothers with a habitually low fish intake and of their infants. Ann Nutr Metab 2008;52(2):157-166. View abstract.
^ 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.
Due to the presence of Omega-3 fatty acids, fish oil has been promoted for relieving depression, sadness, anxiety, restlessness, mental fatigue, stress, decreased sexual desire, suicidal tendencies, and other nervous disorders. Researchers at the Case Western Reserve University School of Medicine in Cleveland, Ohio, in their research publication titled “Fish Oils and Bipolar Disorder: A Promising but Untested Treatment”, state that fish oil can be useful in mood stabilization and the treatment of bipolar disorders. It is unsurprising, therefore, that countries where fish is frequently eaten, have a low incidence of depression. Similarly, research conducted on prisoners has shown that when prisoners were given seafood containing a higher amount of omega-3 fatty acids, there was a significant drop in the homicide rate and the frequency of violence. Intake of fish is also a good remedy for depression. Findings of a research study suggest that fish consumption may be beneficial for women’s mental health and reduces the risk of developing depression in women.
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.
Omega-3s have been studied in various mood disorders, such as postpartum depression, with some promising results. In bipolar disorder (manic depression), the omega-3s may be most effective for the depressed phase rather than the manic phase of the illness. The omega-3s have also been proposed to alleviate or prevent other psychiatric conditions including schizophrenia, borderline personality disorder, obsessive compulsive disorder, and attention deficit disorder. However, there is still not enough evidence to recommend the omega-3s in these conditions.
Your body also needs omega-6s, another type of fatty acid, to function properly and prevent disease. Unfortunately, these are found in much more abundance than omega-3s in the standard American diet, although your body craves a 1:1 ratio to keep inflammation low. Most modern diets contain a ratio closer to 20:1 or 30:1 omega-6 to omega-3 fatty acids.
You “beat me to the punch.” despite labels, cured meats , aged fats, as well as those heated to a high enough temperature all have trans bonds. Fish that offer high amounts of Omega-3 also often are high in mercury. I was fortunate to have a very good teacher for experimental design. One should be careful to assume that a study actually measures what it claims to and without “confounders” Confounders are parts of the study that complicate the the “logic” of the design. Also, were other fat contents measured or controlled? It would be reasonable to suspect that those with higher levels of Omega-3 could have higher levels of Omega-6, fats in general , High levels of protein, higher levels of testosterone, or lower levels of certain hormones. In addition, statistical studies do not and have never indicated a causal relationship. I have a fear of how much we have begun to rely on statistical correlational studies which are at the end of the day”soft” science.
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: 

The Department of Ecology of the State of Washington has ranked various seafood based on its EPA and DHA concentrations. The highest-ranking seafood is mackerel, excluding King mackerel, that has a concentration of 1,790 milligrams of combined EPA and DHA per 100 grams, followed by salmon at 1,590; bluefin tuna has between 1173 and 1504 milligrams; sardines contain 980 milligrams; albacore tuna has 862 milligrams; bass has 640 milligrams; tuna has 630 milligrams; trout and swordfish have 580 milligrams; and walleye has 530 milligrams. Other seafood, which includes sea bass, clams, lobster, scallops, catfish, cod, pollock, crayfish and scallops contains between 200 and 500 milligrams of EPA and DHA per 100 grams. Breaded fish products rank lowest on the list with only 0.26 milligram per 100 grams.
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

Your body can convert some ALA into EPA and then DHA, but not enough to meet all your body’s needs but the best way to assure you are getting enough heart healthy fats is to eat foods high in the omega 3 fats, and if you can’t or don’t get enough of these necessary fats in your diet, you might consider taking an omega 3 supplement to boost these needed fats. More on this later.
There’s evidence that points to the mechanism behind the effects of fish oil on body composition, showing that fat burning at rest is increased with 6 grams/day of fish oil supplementation, and additional research suggests that higher omega-3 levels may be helpful for enhancing satiety during weight loss efforts. Other evidence suggests that fat loss may be a side-effect of the reduction in inflammation that fish oil can help with. Any way you look at it, supporting your dietary habits with 4 or more grams of fish oil per day is probably a good idea!
EPA, which is eicosapentaenoic acid, and DHA, which is docosahexaenoic acid, are two types of omega-3 fatty acids that are most commonly found in seafood. These polyunsaturated fats are known to have preventative health benefits and have been studied for their role in treating certain chronic conditions. In addition to dietary sources, certain supplements such as fish oil, are also rich in EPA and DHA.
Henriksen, C., Haugholt, K., Lindgren, M., Aurvag, A. K., Ronnestad, A., Gronn, M., Solberg, R., Moen, A., Nakstad, B., Berge, R. K., Smith, L., Iversen, P. O., and Drevon, C. A. Improved cognitive development among preterm infants attributable to early supplementation of human milk with docosahexaenoic acid and arachidonic acid. Pediatrics 2008;121(6):1137-1145. View abstract.
On September 8, 2004, the U.S. Food and Drug Administration gave "qualified health claim" status to EPA and DHA omega−3 fatty acids, stating, "supportive but not conclusive research shows that consumption of EPA and DHA [omega−3] fatty acids may reduce the risk of coronary heart disease".[98] This updated and modified their health risk advice letter of 2001 (see below).
McNamara, R. K., Able, J., Jandacek, R., Rider, T., Tso, P., Eliassen, J. C., Alfieri, D., Weber, W., Jarvis, K., DelBello, M. P., Strakowski, S. M., and Adler, C. M. Docosahexaenoic acid supplementation increases prefrontal cortex activation during sustained attention in healthy boys: a placebo-controlled, dose-ranging, functional magnetic resonance imaging study. Am J Clin Nutr 2010;91(4):1060-1067. View abstract.
According to the Cardiovascular Research Institute in Maastricht in Netherlands, “Epidemiological studies show that replacing fat with carbohydrates may even be worse [than the Western-type high-fat diet] and that various polyunsaturated fatty acids (FA) have beneficial rather than detrimental effects on CVD (cardiovascular disease) outcome.” This includes fish-oil fatty acids with anti-inflammatory properties, which can help prevent and reverse a plethora of cardiovascular diseases. (19)
Maximizing the benefits you get from omega-3s is highly dependent on how they are absorbed and transported throughout your body. Although these fatty acids are water soluble, they cannot be easily transported into your blood in their free form. Therefore, they need to be packaged in lipoprotein vehicles for them to be better absorbed into your bloodstream.

Thanks for the informative article. You mentioned that those taking high doses of DHA should supplement it with trace amounts of GLA. What GLA source would you recommend, and how much per day? I will be taking around 3400 mg of epa and 2200 mg DHA per day. I've heard that Borage Oil is more potent in GLA than evening primrose, but that it can lead to increased clotting and increased risk of heart attack, stroke, etc due to increased thromboxane B2. The main reason I want to stay away from the primrose is because it is extremely rich in linoleic acid. Thanks.


The omega-3 index may also be helpful for assessing health risks beyond cardiovascular disease. Studies are currently investigating the relationship between omega-3 index levels and mental health issues, like depression (15, 16, 17), cognitive functioning (18, 19), body weight (20), as well as eye health issues, like macular degeneration (21), to name just a few.
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).
Due to the presence of Omega-3 fatty acids, fish oil has been promoted for relieving depression, sadness, anxiety, restlessness, mental fatigue, stress, decreased sexual desire, suicidal tendencies, and other nervous disorders. Researchers at the Case Western Reserve University School of Medicine in Cleveland, Ohio, in their research publication titled “Fish Oils and Bipolar Disorder: A Promising but Untested Treatment”, state that fish oil can be useful in mood stabilization and the treatment of bipolar disorders. It is unsurprising, therefore, that countries where fish is frequently eaten, have a low incidence of depression. Similarly, research conducted on prisoners has shown that when prisoners were given seafood containing a higher amount of omega-3 fatty acids, there was a significant drop in the homicide rate and the frequency of violence. Intake of fish is also a good remedy for depression. Findings of a research study suggest that fish consumption may be beneficial for women’s mental health and reduces the risk of developing depression in women.
Omega 3 fatty acids are monounsaturated fats that come from food sources—primarily cold water fish (eg, salmon, trout, tuna, mackerel, and herring)—that contain EPA (eicosapentaenoic acid) and docosahexaenoic acid (DHA). Other fatty acids are derived from plant-derived sources of food—including nuts (especially walnuts) and seeds (eg, flax, chia, sunflower)—that have primarily ALA (alpha-linolenic acid).

To reach the required dose of EPA for treating certain conditions such as depression, CVD or CFS/ME you would need to take approximately 1-2 grams of ‘free EPA’ daily. Even with a concentrated omega-3 fish oil supplement, offering 180 mg excess EPA over DHA, this would require 10-20 capsules daily – significant in terms of volume and cost, and not efficient in terms of uptake in the body as our capacity for fat absorption is limited. The most effective and efficient way to ensure high EPA uptake in the body rapidly is to supplement with pure EPA for a minimum of 3-6 months.
Those foods provide enormous amounts of other nutrients that are good for you. nSo it is way better to eat those foods than to take fish oil. With that said, some people find it very difficult to get vitamin A or vitamin D, and particularly for vitamin A, cod liver oil may be a very important source of that vitamin. Cod liver oil is a form of fish oil that happens to be high in the fat-soluble vitamins. Vitamin A is best found in liver. It’s better in my opinion to eat liver once a week, but there are a lot of people out there who are not going to eat liver once a week. So if you are using cod liver oil to get the vitamins that you can’t get from food—and I should point out that vitamin A can also be derived from plant foods, but many people genetically or for other reasons don’t derive it very well from plant foods.
In our analysis, most of the included studies showed a positive Hedges g toward a beneficial effect of omega-3 PUFAs in anxiety reduction, although not all findings were statistically significant. However, after merging of these effect sizes from all of the included studies, the main result showed significant findings in our meta-analysis. Despite the significant heterogeneity, no significant publication bias was found among these 19 studies.
Khandelwal, S., Demonty, I., Jeemon, P., Lakshmy, R., Mukherjee, R., Gupta, R., Snehi, U., Niveditha, D., Singh, Y., van der Knaap, H. C., Passi, S. J., Prabhakaran, D., and Reddy, K. S. Independent and interactive effects of plant sterols and fish oil n-3 long-chain polyunsaturated fatty acids on the plasma lipid profile of mildly hyperlipidaemic Indian adults. Br.J.Nutr. 2009;102(5):722-732. View abstract.
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]
To our knowledge, this is the first systematic review and meta-analysis to examine the anxiolytic effects of omega-3 PUFAs in individuals with anxiety symptoms. The overall findings revealed modest anxiolytic effects of omega-3 PUFAs in individuals with various neuropsychiatric or major physical illnesses. Although participants and diagnoses were heterogeneous, the main finding of this meta-analysis was that omega-3 PUFAs were associated with significant reduction in anxiety symptoms compared with controls; this effect persisted vs placebo controls. Furthermore, the association of treatment with reduced anxiety symptoms of omega-3 PUFA were significantly higher in subgroups with specific clinical diagnoses than in subgroups without clinical conditions.
A 2014 meta-analysis of eleven trials conducted respectively on patients with a DSM-defined diagnosis of major depressive disorder (MDD) and of eight trials with patients with depressive symptomatology but no diagnosis of MDD demonstrated significant clinical benefit of omega-3 PUFA treatment compared to placebo. The study concluded that: "The use of omega-3 PUFA is effective in patients with diagnosis of MDD and on depressive patients without diagnosis of MDD."[42]
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).
Disclaimer: The entire contents of this website are based upon the opinions of Dr. Mercola, unless otherwise noted. Individual articles are based upon the opinions of the respective author, who retains copyright as marked. The information on this website is not intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice. It is intended as a sharing of knowledge and information from the research and experience of Dr. Mercola and his community. Dr. Mercola encourages you to make your own health care decisions based upon your research and in partnership with a qualified health care professional. If you are pregnant, nursing, taking medication, or have a medical condition, consult your health care professional before using products based on this content.
Wright, S. A., O'Prey, F. M., McHenry, M. T., Leahey, W. J., Devine, A. B., Duffy, E. M., Johnston, D. G., Finch, M. B., Bell, A. L., and McVeigh, G. E. A randomised interventional trial of omega-3-polyunsaturated fatty acids on endothelial function and disease activity in systemic lupus erythematosus. Ann.Rheum.Dis. 2008;67(6):841-848. View abstract.

A 2014 meta-analysis of eleven trials conducted respectively on patients with a DSM-defined diagnosis of major depressive disorder (MDD) and of eight trials with patients with depressive symptomatology but no diagnosis of MDD demonstrated significant clinical benefit of omega-3 PUFA treatment compared to placebo. The study concluded that: "The use of omega-3 PUFA is effective in patients with diagnosis of MDD and on depressive patients without diagnosis of MDD."[42]


After just seven days, those supplementing with krill had their CRP levels reduced by 19.3%, while in the placebo group, CRP levels rose by 15.7%. Even more impressive, the krill benefit was long-lasting. The krill group’s CRP levels continued to fall by 29.7% at 14 days, and 30.9% at 30 days. More importantly from the patients’ points of view, the krill oil supplement reduced pain scores by 28.9%, reduced stiffness by 20.3%, and reduced functional impairment by 22.8%.
Jump up ^ Abdelhamid, Asmaa S; Brown, Tracey J; Brainard, Julii S; Biswas, Priti; Thorpe, Gabrielle C; Moore, Helen J; Deane, Katherine HO; AlAbdulghafoor, Fai K; Summerbell, Carolyn D; Worthington, Helen V; Song, Fujian; Hooper, Lee (18 July 2018). "Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease". Cochrane Database of Systematic Reviews. doi:10.1002/14651858.CD003177.pub3.
On September 8, 2004, the U.S. Food and Drug Administration gave "qualified health claim" status to EPA and DHA omega−3 fatty acids, stating, "supportive but not conclusive research shows that consumption of EPA and DHA [omega−3] fatty acids may reduce the risk of coronary heart disease".[98] This updated and modified their health risk advice letter of 2001 (see below).

And in osteoarthritis, when a DHA/EPA formulation was added to chondroitin sulfate, people experienced more complete relief of symptoms such as stiffness and pain. One study found a significant increase in walking speed in people who supplemented with fish oil versus those who did not.79,80 As with the beneficial results seen in people with bone loss, these positive findings may have been the result of the decreased inflammatory destruction of joint cartilage.81

Heart disease. Eating fish can be effective for keeping people with healthy hearts free of heart disease. People who already have heart disease might also be able to lower their risk of dying from heart disease by eating fish. The picture is less clear for fish oil supplements. For people who already take heart medications such as a "statin" and those who already eat a decent amount of fish, adding on fish oil might not offer any additional benefit.
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