Key takeaways
- Omega-3s may benefit various conditions, including depression, neurocognitive disorders, heart disease, and eye issues.
- Fish oils come from fatty or oily fish, such as trout, mackerel, tuna, herring, sardines, and salmon. They contain omega-3 fatty acids, and many contain vitamins A and D.
- Omega-3 supplements may have a low risk of adverse effects. Potential side effects include gastrointestinal upset, an unpleasant taste, and bad-smelling breath or sweat.
Many people use fish oil and omega-3 supplements for their potential health benefits. A diet rich in omega-3 fatty acids may help prevent heart disease, protect brain and eye health, and contribute to fetal development.
However, some studies on omega-3 supplement use have mixed results, and it is unclear whether or not supplements are helpful.
Omega-3 fatty acids are fats
Two types are plentiful in oily fish: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Meanwhile, alpha-linoleic acid (ALA), mainly occurs in plant-based foods, such as flaxseed.
Omega-3 is present throughout the body, especially in the brain, retina, and sperm cells. The body cannot produce omega-3 on its own, so people need to obtain it from dietary sources.
Scientists have linked omega-3 to several health conditions. However, it is not always clear whether or not taking additional omega-3 can offer benefits.
The following sections outline some of these conditions and some other health benefits that omega-3 may provide.
Multiple sclerosis
A
The review suggests that fish oil supplements may help reduce inflammation and the relapsing rate and improve quality of life in people with MS.
More research is necessary to understand the full extent of these potential benefits.
Cancer
Omega-3 fatty acids may help to activate certain proteins that affect cell maintenance and repair, which could offer benefits in cancer treatment.
However, more research is necessary before healthcare professionals begin to use omega-3 fatty acids as part of cancer treatment.
Depression
A 2023 observational study found that combining omega-3 fatty acid supplements with antidepressant medication led to significantly higher improvements in symptoms than antidepressants alone.
According to a 2020 study, omega-3s’ benefits may also apply to people with perinatal depression, regardless of whether they are pregnant or in the postpartum period.
The Dietary Guidelines for Americans recommends that people who are pregnant or breastfeeding should eat
- anchovies
- clams
- haddock
- shrimp
- salmon
- whitefish
Key terms explained
- Perinatal: The perinatal period includes pregnancy and the year following birth.
- Postpartum: The period immediately after birth.
Other psychiatric and cognitive conditions
In addition to depression,
Some research suggests that omega-3 supplementation may help prevent cognitive decline. However, more studies are necessary to confirm these benefits.
Heart and cardiovascular benefits
According to a 2024 review, omega-3 fatty acids in fish oils may help prevent:
The
Eye health
Some evidence suggests that getting an adequate intake of omega-3 may help protect eye health.
Optometrists
For example, a
Epilepsy
Epilepsy is a neurological condition. Some
More research into the effect of omega-3 supplements on epilepsy is necessary.
Healthy fetal development
A 2018 article suggests higher levels of omega-3 fatty acids during pregnancy may contribute to the following benefits:
- lower amounts of preterm birth
- lower risk of low birthweight in infants
- lower risk of severe infant sickness, death, or neonatal intensive care
The study did not observe any effects on neonatal depression or adverse effects for the pregnant person.
People can speak with a healthcare professional about the best diet during pregnancy.
COVID-19
A 2024 trial suggests that omega-3 fatty acid supplements may positively affect anti-inflammatory and metabolic pathways, which may benefit people with COVID-19.
However, further research is necessary to understand these benefits.
Although a doctor may recommend supplements to some people, they
Animal-based sources of omega-3
- oily fish, such as sardines, tuna, and salmon
- other seafood, such as oysters and shrimp
- eggs, especially those fortified with omega-3
- fish liver oils, such as cod liver oil
Vegetable-based alternatives to fish oil for omega-3 include:
- flaxseed oil
- chia seeds
- canola oil
- soybean oil
- walnuts
When choosing fish, it is worth checking Seafood Watch to ensure that one’s choices are sustainable.
People who follow a healthy, balanced diet may not need to use supplements. However, omega-3 supplements are unlikely to cause any severe adverse effects, according to the
Potential mild side effects include:
Other potential risks may include increased risk of bleeding, pollutants such as heavy metals, and a risk of atrial fibrillation.
The Food and Drug Administration (FDA) does not regulate the quality or purity of supplements. It is, therefore, essential to buy them from a reputable source.
People can speak with a healthcare professional before taking fish oil supplements to ensure they are safe.
Further resources
For more in-depth resources about vitamins, minerals, and supplements, visit our dedicated hub.
Omega-3 is an essential nutrient that most people can obtain from dietary sources.
Consuming more fish oil and omega-3s may offer some health benefits. If people cannot get enough through dietary sources, a healthcare professional may recommend supplements.
Anyone considering taking supplements should first check with a healthcare professional to ensure it is safe.