The Food and Drug Administration (FDA) considers fish oil supplements to be "generally regarded as safe" or GRAS. And certainly when used as an anti-inflammatory, fish oil allows for fewer severe side effects than prescribed non-steroid anti-inflammatory drugs (NSAID). But as with everything there are some side effects.
With extended use or high doses of fish oil, gastrointestinal discomfort, reflux or diarrhea are common side effects. Additionally, if you ingest a lot of fish oil, the levels of vitamin E in your blood can be lowered. So, many marketers of fish oil supplements will add vitamin E to their products. And some people remark on the fishy taste that lingers in their mouths.
People with a fish allergy should not use fish oil. There are also some medical conditions which preclude use of such supplements. Since fish oil may reduce clotting in the blood anyone taking medications such as Coumadin or NSAIDs which thin the blood should not ingest fish oil.
Another factor for consideration is the prevalence of pollution in our water and its impact on fish. Certain types of fish carry elevated levels of PCBs or dioxins or mercury. Toxins such as methylmercury do pose a health threat to people who ingest large quantities of shark, tuna or swordfish. Yet, fish oil is deemed non-toxic because mercury only builds up in the flesh of fish, not in its oils.
The most immediately noticeable side effects of taking fish oil supplements are likely to be fishy breath, burping, heartburn and possibly nausea or diarrhea. Taking supplements with meals or freezing them can minimize these problems.
Taking high doses of fish oil may reduce the ability of your blood to clot, causing excessive bleeding. Taking them for a long period of time may lead to vitamin E deficiency and may increase risk for anemia in menstruating women. Fish oil supplements may also interact with blood thinners and blood pressure medications, increasing the effect of these drugs. For all these reasons, be sure to talk to your doctor before taking fish oil supplements.
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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.