Fish Oils and Omega-3 Oils: Benefits, Foods, and Risks


Fish oils come from fatty or oily fish such as trout, mackerel, tuna, herring, sardine, and salmon. They contain omega-3 fatty acids and many contain vitamins A and D.

Many people use fish oil and omega-3 supplements because they believe they have health benefits.

American College of Cardiology and American Heart Association (ACC / AHA) guidelines recommend eating fish as part of a heart-healthy diet. In fact, eating a diet high in omega-3 fatty acids can help prevent heart disease, protect brain and eye health, and contribute to the development of the fetus.

However, studies of supplement use have produced mixed results and it is unclear whether or not supplements are helpful.

In this article, you will learn more about fish oils and omega-3 fatty acids, including some potential health benefits and some good food sources.

Omega-3 fatty acids are fats that are commonly found in plants and marine life.

There are two types of fatty fish: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Alpha-linoleic acid (ALA) is now mainly found in plant-based foods such as flaxseed.

Omega-3 is present throughout the body, especially in the brain, retina, and sperm. However, the body cannot produce omega-3 on its own, so people must get it from food sources.

Scientists have linked omega-3s to a number of health conditions. However, it is not always clear whether or not taking additional omega-3s can provide benefits.

The following sections describe some of these conditions and some other health benefits that omega-3 can provide.


Survey data from 2020 suggest that women who take probiotics, vitamin D, fish oil supplements, or a combination thereof are at a slightly lower risk of developing COVID-19.

However, this research has not yet been peer reviewed and the results are far from conclusive.

In fact, experts have warned against using supplements to prevent infection with the virus.

For more information on the COVID-19 outbreak and advice on how to prevent and treat it, please visit our live updates page and our coronavirus hub.

multiple sclerosis

Some people with multiple sclerosis (MS) take omega-3 because it can have protective effects on the brain and nervous system.

However, at least one study has found that omega-3 supplements do not reduce disease activity in MS.

Prostate cancer

Some research has shown that eating a diet high in omega-3 fatty acids can prevent prostate cancer. However, a 2013 study found that high fish oil intake may actually increase the risk of high-grade prostate cancer.

The exact relationship between omega-3s and various cancers remains unclear, but a number of studies have found no evidence that omega-3s either increase or decrease the risk of various cancers.

Postpartum Depression

People with low omega-3 levels during pregnancy and while breastfeeding may be more prone to postpartum depression.

The authors of a 2018 review concluded that taking fish oil supplements around this time may help reduce your risk of depression.

However, people should avoid eating fish that are high in mercury, such as shark and king mackerel, during pregnancy. Some good alternatives are canned tuna, salmon, pollock, and catfish.

Memory and Other Psychological Benefits

In addition to postpartum depression, some studies suggest that EPA and DHA might help treat various neuropsychiatric disorders. These include:

Some studies have shown that omega-3 supplementation can help prevent cognitive decline, especially in older adults. However, their findings are inconclusive, according to a 2019 review.

More research is needed to confirm these benefits.

Cardiovascular benefits

Omega-3 fatty acids in fish oils can help prevent heart disease and stroke, according to the AHA.

Specifically, omega-3s can help manage:

A 2013 study found that people who took fish oil supplements for more than 1 month had better cardiovascular function on psychologically stressful tests.

In 2012, researchers found that fish oil appeared to help stabilize atherosclerotic lesions due to its anti-inflammatory properties.

The AHA recommends eating fish, and especially oily fish, at least twice a week. They say this can reduce the risk of cardiovascular disease.

In 2012, however, a review of 20 studies involving nearly 70,000 people found “no compelling evidence” linking fish oil supplements to a lower risk of heart attack, stroke, or premature death.

Vision loss and eye health

Some evidence suggests that getting enough omega-3s can help protect eye health.

In a 2012 study, mice that received omega-3 supplements for 6 months appeared to have better retinal function and a lower risk of age-related vision loss than mice that did not receive these supplements.

Opticians often recommend taking omega-3 supplements to aid eye health, although scientific evidence does not always support their use for this purpose. In some cases, according to some experts, eating a healthy diet may be more beneficial than taking supplements.

For example, scientists who examined data from 4,202 people in Holland in 2019 found that those who consumed fresh fruits and vegetables and two servings of fish per week were less likely to develop age-related macular degeneration than those who did not.

Some people use omega-3 supplements for dry eyes. However, in 2018, a year-long study of 349 people with moderately to severely dry eyes found no evidence that taking supplements was any more helpful than taking a placebo for this purpose.


Epilepsy is a neurological disease. Some studies have shown that taking omega-3 supplements can help reduce the number of seizures in a person.

However, a 2018 review found no conclusive evidence that this can help prevent symptoms.

Healthy fetal development

Consuming omega-3s can promote the development of the fetus, especially the brain and eyes. This is one of the reasons why experts recommend consuming oily fish while pregnant.

However, it is important not to eat high mercury fish such as shark and king mackerel during this time.

In 2011, scientists concluded that consuming omega-3s during pregnancy can improve memory function in school-age children.


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