Omega-3 Fatty Acids
Despite some evidence linking depression with low levels of omega-3 fatty acids, there is currently no convincing evidence that omega-3 fatty acids alone can relieve depression. There is also limited evidence that omega-3 fatty acids given in combination with antidepressant drugs can relieve depression, but this needs to be confirmed before the routine use of omega-3 fatty acid supplements can be recommended for depression.
Circumstantial evidence has suggested a link between omega-3 levels and behavior and mood disorders, such as depression, findings that have attracted widespread attention. Investigators pooled the results of published studies that evaluated the effect on depression of omega-3 fatty acid supplements alone or in combination with established antidepressant drugs.
There was little convincing evidence that omega-3 fatty acids alone can alleviate symptoms of depression and only limited evidence to back their use as a supplement to established antidepressant drugs.
In nine studies, fish oil supplements were generally well tolerated. There have been concerns that fish oil supplements may contain environmental toxins, such as dioxins, PCBs, or mercury. Therefore, it is important not to exceed the maximum recommended doses. Because fish oil supplements contain vitamin A, pregnant women should take only low-dose omega-3 supplements, because of the potentially harmful effects of high levels of vitamin A on the fetus.