From the time of your pregnancy through your child's later life, omega-3 fats DHA and EPA have a radically important role in her brain health and other functions. I recommend supplementing with krill oil before and during pregnancy, and while you breastfeed. Babies receive DHA through your breast milk, so continuing breastfeeding through the first year will give your child a great headstart for health and success.
Jump up ^ Kwak SM, Myung SK, Lee YJ, Seo HG (May 2012). "Efficacy of omega-3 fatty acid supplements (eicosapentaenoic acid and docosahexaenoic acid) in the secondary prevention of cardiovascular disease: a meta-analysis of randomized, double-blind, placebo-controlled trials". Archives of Internal Medicine. 172 (9): 686–94. doi:10.1001/archinternmed.2012.262. PMID 22493407.
The chemical structures of EPA and DHA are very similar and they compete for uptake and processing resources. During digestion, the triglyceride molecules in standard fish oil are broken down into a mono glycerol and two free fatty acids, small enough to be absorbed into cells of the gut lining. More often than not, DHA is the fatty acid that remains attached to the glycerol backbone, meaning in essence that DHA gets a ‘free pass’ into the gut, while the remaining free fatty acids (more often EPA) must reattach onto a glycerol molecule or risk being oxidised and used as fuel. The implication of this is that DHA levels in our cells are often concentrated at the expense of EPA after absorption when taking EPA and DHA in the standard ratio of 1.5 to 1.
All people need to consume omega-3 fats regularly. The recommended daily intake for adults is 1.6 grams for males  and 1.1 grams for females, according to the National Institutes of Health. The omega-3 family encompasses numerous fatty acids, but three primary forms are eicosapentaenoic acid, docosahexaenoic acid, and alpha-linolenic acid. The first two forms primarily occur in fish, such as salmon, mackerel, and tuna. The third can be found in plant oils, including flaxseed, soybean, walnut, and canola oils.

There are numerous omega-3 sources with varying proportions of EPA and DHA, and the balance of EPA and DHA in a supplement influences the actions of these fats in the body. For more information about the different types of omega-3 sources and which are most suited for your individual needs, read our page on the different types of omega-3 supplements
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.
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.
A Pregnancy Prerequisite: Omega-3 fatty acids directly affect brain development, making it crucial for expectant mothers. Additionally, research indicates they decrease a mother's risk of depression. When the mother doesn't have enough of these essential fatty acids, the baby borrows from her. Some prenatal vitamins now include omega-3s, so be sure to check the label or grab a handful of walnuts each day.
Omega-3 fatty acids are frequently in the news regarding their health benefits (or doubts in some cases). Two types of omega-3s in particular - eicosapentaenoic acid (EPA) and docohexaenoic acid (DHA) – are known to be essential fatty acids. “Essential” refers to the fact that our cells need these fatty acids in order to function normally. But the body cannot make them from other fats, which means it’s “essential” we supply them in our diet or through supplementation.
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).

Under these conditions, it may make sense to try fish oil even at higher doses than what I recommended. There is some evidence that krill oil will get the omega-3 fatty acids better into the brain in the psychiatric conditions that I listed. And there is some evidence that EPA-rich fish oils are better than DHA-rich fish oils for some of those psychiatric conditions as well. So there’s room to play around with the different possibilities if those things apply to you. But for the average case, limit the fish oil to 250 milligrams of EPA and DHA combined when you take it, but in all cases, go for food first, and go for fish oil only after you have exhausted those possibilities.
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
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]

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.

Today the only Food and Drug Administration (FDA)-approved form of dietary omega-3 FA supplement is Lovaza (omega-3-acid ethyl esters; GlaxoSmithKline), which contains 375 mg of DHA and 465 mg of EPA per 1 g capsule. The myriad of dietary supplements of fish oil, including Kosher capsules, vary from comparable content to insignificant amounts, and for the most part can include other fats and cholesterols. In comparison, to achieve approximately 1 g of EPA and DHA in a meal, 12 ounces of canned light tuna, 2 to 3 ounces of sardines, 1.5 to 2.5 ounces of farmed Atlantic salmon, or 20 ounces of farmed catfish must be consumed (Table 1).65 Unfortunately, potentially high levels of harmful pollutants offset this source of omega-3 FA. The FDA action level for unacceptably high mercury content in fish is 1.0 μg/g. The mercury level in most fish is at or below 0.1 μg/g, but tilefish, swordfish, and king mackerel have high levels of mercury. The majority of fish species also contain <100 ng/g of polychlorinated biphenyls, which is below the FDA action level of 2000 ng/g. Dioxins, which do not have FDA action levels, are present in the majority of marine life.66
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.
Peroxides can be produced when fish oil spoils. A study commissioned by the government of Norway concluded there would be some health concern related to the regular consumption of oxidized (rancid) fish/marine oils, particularly in regards to the gastrointestinal tract, but there is not enough data to determine the risk. The amount of spoilage and contamination in a supplement depends on the raw materials and processes of extraction, refining, concentration, encapsulation, storage and transportation.[51] reports in its review that it found spoilage in test reports it ordered on some fish oil supplement products.[52]

A, Subgroup meta-analysis of the anxiolytic effect of omega-3 polyunsaturated fatty acids (PUFAs) based on an underlying specific clinical diagnosis or not. The anxiolytic effect of omega-3 PUFAs was not significant in the subgroup of participants without specific clinical conditions (k, 5; Hedges g, –0.008; 95% CI, –0.266 to 0.250; P = .95) but was significant in the subgroup of participants with specific clinical diagnoses (k, 14; Hedges g, 0.512; 95% CI, 0.119-0.906; P = .01). Furthermore, the association of treatment with reduced anxiety symptoms of omega-3 PUFAs were significantly stronger in subgroups with specific clinical diagnoses than in subgroups without specific clinical conditions (P = .03). B, Subgroup meta-analysis of the anxiolytic effect of omega-3 PUFAs based on different mean omega-3 PUFA dosages. The anxiolytic effect of omega-3 PUFAs was not significant in subgroups of mean omega-3 PUFA dosages less than 2000 mg/d (k, 9; Hedges g, 0.457; 95% CI, –0.077 to 0.991; P = .09) but was significant in the subgroup of mean omega-3 PUFA dosage of at least 2000 mg/d (k, 11; Hedges g, 0.213; 95% CI, 0.031-0.395; P = .02).

Krill oil is joining the toolkit for fighting arthritis, thanks to its exceptional anti-inflammatory properties resulting from its phospholipid form of omega-3s. A study in mice with experimental arthritis showed that krill oil supplements reduced arthritis scores and markedly diminished joint swelling. When examined under a microscope, the animals’ joints were remarkably free of inflammatory infiltrates of immune system cells.85

Two psychiatrists (P.-T.T. and T.-Y.C.) separately performed a systematic literature search of the PubMed, Embase, ProQuest, ScienceDirect, Cochrane Library, ClinicalKey, Web of Science, and databases to March 4, 2018. Because we presumed some clinical trials would use investigating scales for some other mood symptoms but also contain symptoms of anxiety, we tried to use some nonspecific medical subject heading terms to include those clinical trials. Therefore, we used the following keywords: omega-3, eicosapentaenoic acid, EPA, DHA, or docosahexaenoic acid; and anxiety, anxiety disorder, generalized anxiety disorder, agoraphobia, panic disorder, or posttraumatic stress disorder. After removing duplicate studies, the same 2 authors screened the search results according to the title and abstract to evaluate eligibility. List of potentially relevant studies were generated for a full-text review. Any inconsistencies were discussed with a third author to achieve final consensus. To expand the list of potentially eligible articles, we performed a manual search of the reference lists of review articles in this area.12,38,39

Pumps the Heart: Where to begin? Omega-3s reduce triglycerides, stabilize your heartbeat, make platelets "less sticky" and can even lower blood pressure. The EPA you get with your daily DHA dose helps prevent artery-blocking clots. In the Iowa Nurses Study (and 3 others), 1 ounce of nuts a day decreased the incidence of heart disease between 20 and 60 percent.
Carrero, J. J., Fonolla, J., Marti, J. L., Jimenez, J., Boza, J. J., and Lopez-Huertas, E. Intake of fish oil, oleic acid, folic acid, and vitamins B-6 and E for 1 year decreases plasma C-reactive protein and reduces coronary heart disease risk factors in male patients in a cardiac rehabilitation program. J.Nutr. 2007;137(2):384-390. View abstract.
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.
There have been numerous clinical trials looking mainly at death, stroke, and cardiac outcomes related to omega 3 consumption, either in food or in supplements. Now the Cochrane Library has published the largest systematic review of these studies to date. Unfortunately, the review shows little benefit from consuming omega 3 fatty acid. This is a fairly extensive review with good statistical power:
For several years now, the fish oil and Alzheimer’s disease connection has been studied with consistent results. The essential fatty acids vital for brain function that are found in fish oil can not only slow cognitive decline, but can help prevent brain atrophy in older adults. A study published in the FASEB Journal looked at the health effects of four- to 17-month dietary supplementation with omega-3 fatty acids and antioxidants. The findings once again confirm the potential for fish oil to be used as a weapon to fend off the onset of cognitive decline and Alzheimer’s disease. (8)
Foods such as meat, eggs, fish and nuts contain omega-3 and omega-6 fatty acids, which the body converts into endocannabinoids – cannabinoids that the body produces naturally, said Aditi Das, a University of Illinois professor of comparative biosciences and biochemistry, who led the study. Cannabinoids in marijuana and endocannabinoids produced in the body can support the body’s immune system and therefore are attractive targets for the development of anti-inflammatory therapeutics, she said.
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.