There are three types of omega-3 fatty acid:
- alpha-linolenic acid (ALA)
- eicosapentaenoic acid (EPA)
- docosahexaenoic acid (DHA)
ALA is mostly present in plant oils, such as chia seeds, flaxseeds, and walnuts. DHA and EPA are mostly present in cold-water fatty fish, such as mackerel, salmon, herring, and sardines.
A person’s body can convert small amounts of ALA into DHA and EPA. According to the Office of Dietary Supplements (ODS), most people in the United States get enough ALA in their diet. Experts have not yet established how much DHA and EPA a person needs.
Beyond the basic maintenance of cells in a person’s body, initial research has linked omega-3 fatty acids with various other health benefits.
However, a lot of the research that demonstrates these links is in the early stages or relies on experiments on animals.
In general, until scientists conduct further research, it is not clear to what extent omega-3 fatty acids benefit a person beyond the basic maintenance of their body’s cells.
The ODS note that studies have found that people who eat fish, which is a key source of omega-3 fatty acids, typically have a lower risk of various long-term illnesses compared with those who do not eat fish.
However, it is not clear whether this is because of the omega-3s that the fish contain or something else. Furthermore, if it is because of the omega-3s that fish contain, it is not clear if a person taking omega-3 supplements will have the same benefits.
May reduce inflammation
According to an article in the British Journal of Clinical Pharmacology, research has shown DHA and EPA to reduce the process of inflammation, which has links to various cardiovascular illnesses.
However, while these effects were evident in animal studies, clinical trials on humans were less conclusive.
People with rheumatoid arthritis appeared to benefit from taking fish-oil supplements, but there was no clear benefit for people with inflammatory bowel disease or asthma.
May reduce the chance of heart attack
According to the ODS, there is some evidence that taking omega-3 supplements may reduce the risk of a person having a heart attack. However, the ODS note that other studies did not find a link between omega-3 supplements and less chance of a person having cardiovascular issues in general.
A review article in the Journal of Physiology and Biochemistry states that this is a controversial area of research that is still up for debate.
According to the National Centre for Complementary and Integrative Health (NCCIH), researchers have shown omega-3s to help lower a person’s triglyceride levels. Triglycerides are fats, and if a person has an excess of these, they are more at risk of cardiovascular diseases.
However, the NCCIH point out that medications that contain omega-3s among other ingredients have approval by the U.S. Food and Drug Administration (FDA) to treat high triglyceride levels, although the same does not apply to omega-3 supplements.
May help combat obesity
An article in The Journal of Nutritional Biochemistry states that research in humans is yet to show omega-3 supplements to help a person lose weight. They may be able to help a person stop putting weight back on, however, although it is not clear precisely how they may do this.
May contribute to infant health
The NCCIH highlight a study that shows that the children of mothers who took a high-dose fish oil supplement were less likely to develop asthma than the children of mothers who took a placebo. However, the NCCIH also note that other studies contradict this finding.
Side effects of taking omega-3 supplements include nausea and headaches.
According to the NCCIH, the side effects from omega-3 supplements are usually mild and might include:
The ODS note that if a person is taking anticoagulants, which are drugs that stop their blood from clotting, then taking high doses of omega-3 supplements may lead to bleeding problems.
Omega-3 fatty acids are an important part of a person’s nutrition and contribute to the basic health of all cells in the body. Most people get enough omega-3 fatty acids in their diet to achieve this.
A key source of omega-3 fatty acids is fish. There is clear evidence that eating more fish can help reduce the chances of a person developing cardiovascular illnesses. However, there has yet to be conclusive evidence that taking omega-3 supplements has similar health benefits.