Fish oil supplements may help ease symptoms of depression in some people. A few studies in adults suggest that omega-3 fatty acids may be beneficial in the treatment of mild to moderate depression. However, studies using fish oil as the primary treatment for severe depression haven't been done.
Fish oil is a good source of omega-3 fatty acids, which play an important role in brain function. People with depression may have low blood levels of brain chemicals called eicosapentaenoic (i-koe-suh-pen-tuh-e-NO-ik) acid (EPA) and docosahexaenoic (doe-koe-suh-hek-suh-e-NO-ik) acid (DHA). EPA and DHA can be found in fish oil.
Supplements aren't the only way to get more omega-3s. Eating fish a few times a week may be the best way to provide your body with enough of these healthy oils. Examples of fish high in omega-3s include sardines, salmon, herring, trout and canned white tuna. Shellfish, including mussels and oysters, also contain omega-3s.
However, if you're pregnant or nursing, due to mercury levels, limit your weekly intake to 12 ounces (340 grams) of a variety of fish. Eat no more than 6 ounces (170 grams) of white (albacore) tuna a week because it's higher in mercury than light canned tuna. Avoid swordfish, tilefish, king mackerel and shark because of their high levels of mercury. And avoid any kind of raw seafood.
Fish oil isn't considered a replacement for treatment of depression, but it may be helpful as an addition to prescribed medications or other treatment. Although more studies are needed to determine exactly what role omega-3s play in depression, it's possible that eating fish high in omega-3s may help lower the risk of depression — and foods high in omega-3s help protect heart health.