In addition to depression, chronic stress leads to loss of volume of the hippocampus—and also causes enlargement of the amygdala, the portion of the brain that regulates anxiety and anger.24 When rats were supplemented with omega-3s during exposure to stress, they showed lower corticosterone levels (a marker of stress), and improved learning on a maze—indicating that the omega-3s helped preserve memory and reduce anxiety.24


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.
Fish oil seems to be a subject of controversy. Some people swear by it, and there are thousands of clinical trials out now trying to study what the latest and greatest thing about the supplement is. The Natural Standard does a really good job collecting and gathering data for those who are interested in delving through what fish oil may or may not be doing to us. Definitive answers, however, may take a little while to get.
Rogers, P. J., Appleton, K. M., Kessler, D., Peters, T. J., Gunnell, D., Hayward, R. C., Heatherley, S. V., Christian, L. M., McNaughton, S. A., and Ness, A. R. No effect of n-3 long-chain polyunsaturated fatty acid (EPA and DHA) supplementation on depressed mood and cognitive function: a randomised controlled trial. Br J Nutr 2008;99(2):421-431. View abstract.

There is some evidence that omega−3 fatty acids are related to mental health,[47] including that they may tentatively be useful as an add-on for the treatment of depression associated with bipolar disorder.[48] Significant benefits due to EPA supplementation were only seen, however, when treating depressive symptoms and not manic symptoms suggesting a link between omega−3 and depressive mood.[48] There is also preliminary evidence that EPA supplementation is helpful in cases of depression.[49] The link between omega−3 and depression has been attributed to the fact that many of the products of the omega−3 synthesis pathway play key roles in regulating inflammation (such as prostaglandin E3) which have been linked to depression.[50] This link to inflammation regulation has been supported in both in vitro[51] and in vivo studies as well as in meta-analysis studies.[33] The exact mechanism in which omega−3 acts upon the inflammatory system is still controversial as it was commonly believed to have anti-inflammatory effects.[52]

Schilling, J., Vranjes, N., Fierz, W., Joller, H., Gyurech, D., Ludwig, E., Marathias, K., and Geroulanos, S. Clinical outcome and immunology of postoperative arginine, omega-3 fatty acids, and nucleotide-enriched enteral feeding: a randomized prospective comparison with standard enteral and low calorie/low fat i.v. solutions. Nutrition 1996;12(6):423-429. View abstract.


Fish oil is a concentrated source of omega-3 fats, which are also called ω-3 fatty acids or n-3 fatty acids. To get more scientific, omega-3s are long-chain polyunsaturated fatty acids, or PUFAs. Our bodies are able to make most of the fats we need need, but that’s not true for omega-3 fatty acids. When it comes to these essential fats, we need to get them from omega-3 foods or supplements.
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]
Another recent study shows that fatty fish consumption can cut the risk of eye-diabetes complications. The researches tracked the seafood consumption of about 3,600 diabetic men and women between the ages of 55 and 80 for nearly five years. The researchers found that people who regularly consumed 500 milligrams each day of omega-3 fatty acid in their diets (equal to two servings of fatty fish per week) were 48 percent less likely to develop diabetic retinopathy than those who consumed less. (23)
Eicosatetraenoic Acid (ETA): ETA is a lesser-known omega-3 fatty acid that also contains 20 carbons, like EPA, but only four bonds instead of five. It is found richly inroe oil and green-lipped mussel and is only recently being recognized for its potent health benefits. Not only is it anti-inflammatory, like the other omega-3s, but ETA can also limit your body’s production of the inflammatory omega-6 fatty acid arachidonic acid (ARA). In fact, ETA redirects the enzyme that normally creates ARA to convert it to EPA instead!
This article had several limitations and the findings need to be considered with caution. First, our participant population is too heterogeneous because of our broad inclusion criteria, which might be true if considering current Diagnostic and Statistical Manual of Mental Disorders or International Classification of Diseases diagnostic systems. However, the novel Research Domain Criteria consider anxiety to be one of the major domains in Negative Valence Systems. Trials should be conducted in populations in which anxiety is the main symptom irrespective of the presence or absence of diagnosis of anxiety disorder. Second, because of the limited number of recruited studies and their modest sample sizes, the results should not be extrapolated without careful consideration. Third, the significant heterogeneity among the included studies (Cochran Q, 178.820; df, 18; I2, 89.934%; P < .001) with potential influence by some outlier studies, such as the studies by Sohrabi et al56 and Yehuda et al,61 would be another major concern. Therefore, clinicians should pay attention to this aspect when applying the results of the current meta-analysis to clinical practice, particularly when considering the subgroups of these 2 studies (ie, subgroups with specific clinical diagnoses, with <2000 mg/d, with EPA <60%, and with placebo-controlled trials).
The current American diet has changed over time to be high in SFA and low in omega-3 fatty acids (12). This change in eating habits is centered on fast food containing high amounts of saturated fat, which has small amounts of essential omega-3 PUFA compared with food prepared in the home (13). Seafood sources such as fish and fish-oil supplements are the primary contributors of the 2 biologically important dietary omega-3 fatty acids, EPA and DHA (14–16). This low intake of dietary EPA and DHA is thought to be associated with increased inflammatory processes as well as poor fetal development, general cardiovascular health, and risk of the development of Alzheimer's disease (AD).
Fish oil is useful in the treatment of arthritis, rheumatism, Raynaud’s symptoms and similar conditions. Using the fish oil can help in reducing the need for large dosages of NSAIDs (non-steroidal anti-inflammatory drugs). The Royal Adelaide Hospital and the University of Newcastle, located in Australia, have reported that fish oil has shown positive effects in the treatment of arthritis. In cases of osteoarthritis, fish oil can be helpful in reducing the impact of enzymes that destroy cartilage.
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.
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.

I've been take Omega 3 for quite a while now. Just recently my eye doctor recommended finding an Omega 3 with at least this amount of 800mg EPA and 600mg DHA. I'm taking this for my dry eyes. So far, along with the eye drops and this product my eyes don't feel like I have sand in them. They don't have a fishy taste or an after taste. I would recommend them.
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.
Participants treated with a daily dose of 2000 mg or more of omega-3 PUFAs showed a significantly greater association of treatment with reduced anxiety symptoms. In addition, participants receiving supplements containing less than 60% EPA showed a significant association, but not those receiving supplements containing 60% or more EPA. The depression literature supports the clinical benefits of EPA-enriched formulations (≥60% or ≥50%) compared with placebo for the treatment of clinical depression.9,13,73-75 This opposite effect of EPA-enriched formations on anxiety and depression is intriguing and possibly linked to a distinct underlying mechanism of omega-3 PUFAs. Exploration of the effects of omega-3 PUFAs on anxiety symptoms is just beginning and studies assessing the dose response anxiolytic effects of omega-3 PUFAs have not yet been performed. Further phase 2 trials of anxiety symptoms among participants with neuropsychiatric illness or physical illness should aim to determine the optimal dose.
Davidson, M. H., Stein, E. A., Bays, H. E., Maki, K. C., Doyle, R. T., Shalwitz, R. A., Ballantyne, C. M., and Ginsberg, H. N. 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(7):1354-1367. 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.
^ Jump up to: a b Casula M, Soranna D, Catapano AL, Corrao G (August 2013). "Long-term effect of high dose omega-3 fatty acid supplementation for secondary prevention of cardiovascular outcomes: A meta-analysis of randomized, placebo controlled trials [corrected]". Atherosclerosis. Supplements. 14 (2): 243–51. doi:10.1016/S1567-5688(13)70005-9. PMID 23958480.
Various scales were used in these studies to evaluate the target outcome of anxiety symptoms: the Yale-Brown Obsessive-Compulsive Scale, Profile of Mood States, State-Trait Anxiety Inventory, Hamilton Anxiety Rating Scale, Generalized Anxiety Disorder questionnaire, Depression, Anxiety, and Stress Scales, Clinician-Administered Posttraumatic Stress Disorder Scale, Beck Anxiety Inventory, visual analog scale of anxiety, Impact of Event Scale–Revised, Conners score anxiety subscale, Neuropsychiatric Inventory, test anxiety severity, Hospital Anxiety and Depression Scale anxiety subscale, and Child Behavior Checklist anxiety subscale. The psychiatric and physical health conditions of the recruited participants also varied widely: general population without specific clinical conditions,36,47,51,55,60 participants with acute myocardial infarction,35 borderline personality disorder,2 mild to severe depression,59 obsessive-compulsive disorder,33 severe accidental injury,49 participants who were traumatized by disaster,54 participants with substance abuse disorder,34 women with premenstrual syndrome,56 children with attention-deficit/hyperactivity disorder,48,53 Alzheimer disease,58 generally healthy undergraduate college students but with test anxiety,61 Parkinson disease,52 and participants with Tourette syndrome.57 Sixteen studies compared the effect of omega-3 PUFA treatment with that of the placebo33,34,36,47-49,51-53,55-61; the other 3 studies were non–placebo controlled trials.35,50,54 The mean (SD) Jadad score of the recruited studies was 3.8 (1.0) (eTable in the Supplement).
FDA pregnancy category C. It is not known whether Fish Oil will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using Fish Oil. It is not known whether omega-3 polyunsaturated fatty acids pass into breast milk or if this could harm a nursing baby. Do not use Fish Oil without telling your doctor if you are breast-feeding a baby. Do not give this medication to anyone under 18 years old.
An animal study involving the omega-3 ETA discovered that subjects experienced a drop in overall inflammation similar to that caused by NSAIDs (non-steroidal anti-inflammatory drugs), but without the dangerous gastrointestinal side effects. The study authors also pointed out that eicosapentaenoic acid seems to be even more potent than the conventional omega-3s found in fish oil supplements (EPA/DHA). (56)

ODS seeks to strengthen knowledge and understanding of dietary supplements by evaluating scientific information, supporting research, sharing research results, and educating the public. Its resources include publications (such as Dietary Supplements: What You Need to Know), fact sheets on a variety of specific supplement ingredients and products (such as vitamin D and multivitamin/mineral supplements), and the PubMed Dietary Supplement Subset

Various scales were used in these studies to evaluate the target outcome of anxiety symptoms: the Yale-Brown Obsessive-Compulsive Scale, Profile of Mood States, State-Trait Anxiety Inventory, Hamilton Anxiety Rating Scale, Generalized Anxiety Disorder questionnaire, Depression, Anxiety, and Stress Scales, Clinician-Administered Posttraumatic Stress Disorder Scale, Beck Anxiety Inventory, visual analog scale of anxiety, Impact of Event Scale–Revised, Conners score anxiety subscale, Neuropsychiatric Inventory, test anxiety severity, Hospital Anxiety and Depression Scale anxiety subscale, and Child Behavior Checklist anxiety subscale. The psychiatric and physical health conditions of the recruited participants also varied widely: general population without specific clinical conditions,36,47,51,55,60 participants with acute myocardial infarction,35 borderline personality disorder,2 mild to severe depression,59 obsessive-compulsive disorder,33 severe accidental injury,49 participants who were traumatized by disaster,54 participants with substance abuse disorder,34 women with premenstrual syndrome,56 children with attention-deficit/hyperactivity disorder,48,53 Alzheimer disease,58 generally healthy undergraduate college students but with test anxiety,61 Parkinson disease,52 and participants with Tourette syndrome.57 Sixteen studies compared the effect of omega-3 PUFA treatment with that of the placebo33,34,36,47-49,51-53,55-61; the other 3 studies were non–placebo controlled trials.35,50,54 The mean (SD) Jadad score of the recruited studies was 3.8 (1.0) (eTable in the Supplement).
The European Journal of Neuroscience published a study in 2013 showing that fish oil reversed all anxiety-like and depression-like behavior changes induced in rats. This is an interesting study because it stresses the importance of supplementing with fish oil at “critical periods of brain development.” (10) This is exactly why I recommend giving fish oil to our kids from early on to help them so they won’t develop anxiety or depression later in life.
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 Japanese notably have the lowest levels of coronary heart disease mortality and atherosclerosis among developed nations — a phenomena that has been largely subscribed to diet. However, even within Japan, a 10-year study of over 41,000 people found that higher intakes of omega-3s were associated with lower risks of nonfatal coronary events (8). A more recent study also found that Japanese with higher omega-3 index levels (10%) had a lower risk of fatal coronary heart disease than those with a lower omega-3 index levels (8%) (9). The study begs the question of whether maybe even the Japanese have room to improve their omega-3 intake and whether 8% should be considered the lower limit of a desirable range.
Most vegan omega-3 supplements are made from seaweed, one of very few plant sources of both EPA and DHA. If you’d rather skip the pills, the real thing provides omega-3s as well as vitamin K, vitamin C, niacin, folate, and choline. Seaweed can be eaten raw (look for it at your local organic or Asian market) or dried — try Annie Chun’s Organic Seaweed Snack, which comes in individual packs and is available in several delicious flavors.
First difference is in the area of omega-6 fatty acid metabolism. Whereas EPA is the inhibitor of the enzyme (D5D) that directly produces AA, DHA is an inhibitor of another key enzyme delta-6-desaturase (D6D) that produces the first metabolite from linoleic acid known as gamma linolenic acid or GLA (6). However, this is not exactly an advantage. Even though reduction of GLA will eventually decrease AA production, it also has the more immediate effect of reducing the production of the next metabolite known as dihomo gamma linolenic acid or DGLA. This can be a disaster as a great number of powerful anti-inflammatory eicosanoids are derived from DGLA. This is why if you use high-dose DHA it is essential to add back trace amounts of GLA to maintain sufficient levels of DGLA to continue to produce anti-inflammatory eicosanoids.
Chemical structure of alpha-linolenic acid (ALA), an essential omega−3 fatty acid, (18:3Δ9c,12c,15c, which means a chain of 18 carbons with 3 double bonds on carbons numbered 9, 12, and 15). Although chemists count from the carbonyl carbon (blue numbering), biologists count from the n (ω) carbon (red numbering). Note that, from the n end (diagram right), the first double bond appears as the third carbon-carbon bond (line segment), hence the name "n-3". This is explained by the fact that the n end is almost never changed during physiological transformations in the human body, as it is more energy-stable, and other compounds can be synthesized from the other carbonyl end, for example in glycerides, or from double bonds in the middle of the chain.

There was no significant association between the Hedges g and mean age (k, 17; P = .51), female proportion (k, 18; P = .32), mean omega-3 PUFA dosage (k, 19; P = .307), EPA to DHA ratio (k, 17; P = .86), dropout rate in the omega-3 PUFA group (k, 18; P = .71), duration of omega-3 PUFA treatment (k, 19; P = .14), Jadad score of randomization (k, 19; P = .10), Jadad score of blindness (k, 19; P = .57), or total Jadad score (k, 19; P = .18).
Healthy cells require a delicate balance of EPA and DHA and the body employs clever mechanisms to support this natural equilibrium. DHA levels are self-regulated through inhibiting the activity of the enzyme delta-6 desaturase – the very enzyme that supports the conversion of EPA into DHA – to ensure levels of DHA do not become too high. It is therefore possible to have too much preformed DHA, if our supplement intake exceeds the body’s needs.
Pregnancy and breast-feeding: Fish oil is LIKELY SAFE when taken by mouth appropriately. Taking fish oil during pregnancy does not seem to affect the fetus or baby while breast-feeding. Women who are pregnant or who may become pregnant, and nursing mothers should avoid shark, swordfish, king mackerel, and tilefish (also called golden bass or golden snapper), as these may contain high levels of mercury. Limit consumption of other fish to 12 ounces/week (about 3 to 4 servings/week). Fish oil is POSSIBLY UNSAFE when dietary sources are consumed in large amounts. Fatty fish contain toxins such as mercury.
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