The Qualities of Fish Oil

Fish oil is rich in two omega-3 fatty acids eicosapentaeonic, or EPA, and docosahexaenoic, DHA. These are essential fatty acids, which mean that your body cannot synthesize them. Fish oil became a popular dietary supplement after the scientific community realized that Greenland Eskimos had a very low incidence of heart disease and arthritis due to a diet heavy in fish oils. Several scientific studies support the health benefits of consuming fish and the fatty oils they contain.

Omega-3 and Its Cardiovascular Effects

According to the American Heart Association, omega-3 fatty acids lower the risk of arrhythmias, modulate triglyceride levels and lower blood pressure. Additionally, fish oils decrease the rate of growth of atherosclerotic plaques, which can cause heart attacks. The American Heart Association recommends eating two servings of fish a week, each serving should 3.5 oz. when cooked. The most recommended fish -- due to their high content of fish oil -- are salmon, mackerel, herring, lake trout, sardines and albacore tuna. To get the full health benefit of eating fish, you should not fry or excessively salt the fish. The American Heart Association also recommends that persons with coronary artery disease consider fish oil supplements, but limit the consumption to 3 g per day.

Fish Oil and Cancer

The American Association for Cancer Research found an association between a high intake of fish and a lower risk of metastatic prostate cancer. They state, however, that this benefit is not necessarily achieved by fish oil supplements. The American Association for Cancer Research basis these conclusions on a study that appeared in the January 2003 issue of "Cancer Epidemiol Biomarkers Prevention." The "European Journal of Cancer" published an article in April 2009 that found that EPA and DHA inhibit production of many important angiogenic mediators that are responsible for tumor growth. They also found a lower incidence of colon, breast cancer and prostate cancer in populations with high intakes of omega-3 fatty acids.

Eicosapentaeonic Acid and Depression

Prof. Basant K. Puri and his collegues at Hammersmith Hospital and Imperial College London were studying schizophrenia and found that both the depression symptoms and schizophrenia responded well to EPA. The American Medical Association published a study in which they found that a dosage of 1 g per day of ethyl-eicosapentaenoate was effective in treating depression in those patients who remained depressed despite adequate standard therapy. The study also showed improvement in the patients' anxiety, sleep, lassitude, libido and suicidal thoughts.

Precautions With Fish

The omega-3 found in fish comes from microalgae or from other fish high in the food chain that have eaten other fish rich in omega-3. One should be careful with shark, sword fish, tilefish and albacore tuna since they can accumulate mercury, polychlorinated biphenyls, or PCBs, and chlordane. Children and pregnant women should eat fish with lower risk of mercury contamination such as light tuna, salmon and pollock.