Many people have heard that fish oil supplements are good for you, but not everyone knows why. Fish oil is a source of omega-3 fatty acids. Omega-3 fatty acids are an essential part of the diet because the body can't make them on its own. Fish oil contains both docosahexaenoic acid, or DHA, and eicosapentaenoic acid, or EPA. Numerous studies have looked at the effects of DHA and EPA on health.
Sources
DHA and EPA are found in cold water fatty fish, including salmon, tuna, mackerel, sardines, shellfish and herring. Fish oil is also available in supplement form. Fish oil capsules contain both DHA and EPA. DHA which is extracted from algae is also available in supplement form without EPA.
Chronic Disease
High intake of fish oil may significantly lower blood pressure, according to MayoClinic.com. However, at this dose level, bleeding is a possible risk, so you should consult a health care provider about using fish oil for blood pressure. Fish oil may also reduce blood triglyceride levels, according to MayoClinic.com. High levels of triglycerides increase risk of heart attack and stroke. Fish oil also reduces the risk of breast, colon and prostate cancer, according to MayoClinic.com. EPA and DHA may also ease symptoms of arthritis, lupus and Raynaud Syndrome, according to the University of Maryland Medical Center.
Mental Health
According to MayoClinic.com, fish oil may help reduce depressive symptoms in some people, possibly because some people with depression have low levels of DHA and EPA in their brains. For people with bipolar disorder, fish oil may slightly reduce depressive symptoms but does not seem to have an effect on manic symptoms, according to a 2007 study by C. Sempels and P. Sienaert in the Dutch journal "Tijdschr Psychiatry." Fish oil may also be useful in treating schizophrenia and borderline personality disorder, according to a 2007 review published by Brian M. Ross and colleagues in "Lipids in Health and Disease." The review also showed a slight benefit for people with attention deficit hyperactivity disorder.
Concerns
People who are allergic to fish should avoid fish oil supplements. Those who are diabetic should consult a health care provider before beginning a supplement regimen because of a slight risk of increased blood sugar. Patients at risk of bleeding and those with low levels of LDL cholesterol should also use caution. Fish oil may also increase the risk of bleeding. Potentially harmful contaminants such as dioxins, methylmercury and polychlorinated biphenyls, or PCBs, are found in some species of fish, but not in fish oil. PCBs are chemicals that lead to adverse health effects, including cancer. Stomach upset is common in those that use fish oil supplements. Fish oil taken long term may lead to a vitamin E deficiency, so many supplements contain vitamin E.
Recommendations
Average Americans consume only about 0.1 to 0.2 grams of EPA and DHA each day. The World Health Organization recommends consuming 0.3 to 0.5 grams of daily EPA and DHA. It's preferable to get enough omega-3 fatty acids through food, but supplements may be advisable in some cases. The American Heart Association recommends eating fish twice per week. You should begin a supplement regimen only with supervision by a medical provider.
References
- MayoClinic.com: Omega-3 fatty acids, fish oil, alpha-linolenic acid
- MayoClinic.com: Fish oil supplements: Can they treat depression?
- "Tijdschr Psychiatry"; The Role of Omega-3 Fatty Acids in the Treatment of Bipolar Disorders: The Current Situation"; Sempels C, Sienaert P; 2007.
- "Lipids in Health and Disease"; Omega-3 Fatty Acids as Treatments for Mental Illness: Which Disorder and Which Fatty Acid?"; Brian M Ross et al; Sept. 2007.
- University of Maryland Medical Center: Docosahexaenoic acid (DHA)
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