Research has shown that fish oil, which is rich in the omega-3 fatty acids EPA and DHA, may be useful in the treatment of depression. Epidemoliogical studies suggest that either a deficiency of omega-3 fatty acids or an imbalance in the ratio of omega-6 and omega-3 fatty acids may be linked to increased rates of depression. Further, a handful of small, well-designed studies support the use of fish oil as an addition to antidepressant therapy.
Not all fish are created equal, however.
The best source of omega-3 fatty acids are wild fish from northern waters. Wild fish eat a lot of algae, which are rich in omega-3 fatty acids. Farm-raised fish should be avoided since they are generally fed foods low in omega-3 fatty acids, such as cornmeal.
Possible heavy metal and pesticide contamination is also an issue that should be considered when purchasing fish or fish oil supplements. The smaller cold-water fish, such as herring, mackerel, salmon and sardines, are your best choices. Larger fish and farmed fish may accumulate toxins, including mercury and polychlorinated biphenyls, in their tissues.
Although fish oil can be obtained by either eating fish or taking fish oil supplements, studies indicate that fish oil supplements are much less likely than fish to contain contaminants, due to the purification that occurs during the manufacturing process. Pregnant women and children, in particular, should take fish oil supplements rather than eating fish in order to avoid this contamination.
Source:
Rakel, David. Integrative Medicine. 2nd ed. Philadelphia: Saunders Elsevier, 2007.
