Omega-3 is a type of polyunsaturated fatty acid. Omega-3 fatty acids are important for overall health and wellbeing.
There are different types of omega-3 fatty acids. These are:
ALA is found mostly in walnuts, some seeds, and some oils. EPA and DHA are found in oily fish and eggs. ALA is converted into EPA and DHA by the body.
Omega-3 and depression have been linked in the following ways.
While there have been a number of studies which have looked at the effectiveness of omega-3 for treating depression, many of these studies are of low quality. More research of better quality is needed.
Some meta-analyses (reviews of many studies) have found that omega-3 helped to reduce depression symptoms, particularly for people who are also taking anti-depressants. One review found that omega-3 only led to very small improvements in depression symptoms.
One meta-analysis of data from 35 trials found that supplements containing mostly EPA-type omega-3 were effective at reducing depression symptoms, but supplements containing mostly DHA-type omega-3 were no more effective than placebos (dummy treatments) at reducing depression symptoms.
There are some reported side effects of fish-oil tablets, including bloating, gas, belching, nausea, bad breath and/or loose stools.
Some supplements can be harmful or ineffective if you take the wrong dose. Talk to your health care professional if you are thinking of taking supplements, including omega-3.
Many foods are high in omega-3 fatty acids. These include oily fish (such as salmon, mackerel, and sardines), eggs, walnuts, some seeds (including hemp and flaxseed), and some oils.
Omega-3 supplements are available at supermarkets, health food shops and pharmacies.
Fish oil supplements may also contain omega-3 fatty acids but the amount will vary. It is important to check the label to see if the supplement contains omega-3.
There some is evidence to suggest omega-3 helps depression, but more studies of better quality are needed. Omega-3 appears to be more effective for people who are also taking anti-depressants, and some types of omega-3 may be more effective than others.
Last reviewed and updated: 1 May 2019