Side Effects Of Omega-3 Oils

Omega-3 oils (omega-3 fatty acids, omega-3s, fish oil) are essential to good health. According to the University of Maryland Medical Center (UMMC), omega-3s benefit heart health, diabetes, lupus, osteoporosis, depression, psychological disorders, skin disorders, macular degeneration, asthma and certain cancers. Omega-3 oils are in foods like cold-water fish, flaxseed and flaxseed oil, and walnuts and can be supplemented in pill form. Omega-3 oils as a supplement may have side effects but can still benefit individuals with certain medical conditions and those who are unable to consume omega-3s through diet.

Bleeding Risk

According to Medline Plus and the National Institutes of Health, omega-3 fatty acids can cause bleeding and high doses have been associated with blood in the urine and nosebleeds. Fish oil specifically may prolong bleeding time, prevent blood from clotting and break down blood clots. The UMMC does not recommend omega-3 supplements for individuals who bruise easily, have a bleeding disorder or who take blood thinners. Blood-thinning medications that may interact negatively with omega-3 supplements include aspirin, warfarin (a.k.a. coumadin) and plavix.

Intestinal Discomfort and Taste

Nausea, diarrhea, burping, acid reflux, heartburn, bloating and abdominal pain are common side effects of omega-3 supplements. Fish oils that contain omega-3s are also associated with a fishy aftertaste that can be a deterrent to taking a supplement, according to a 2003 article in "Circulation," a publication of the American Heart Association. To minimize intestinal side effects, Medline Plus recommends taking omega-3 supplements with food and starting with a low dose that gradually increases.

Hypotension

Hypotension, or low blood pressure, is a side effect of omega-3 supplements, according to Medline Plus. This may benefit individuals who have high blood pressure (hypertension) but can be detrimental in people with existing hypotension as well as those who take medications to lower blood pressure.

Hyperglycemia

According to the UMMC, fish oil supplements may cause hyperglycemia, a condition characterized by high blood sugar. Fish oil supplements may also interact with diabetic medications that lower blood sugar. Currently, it does not appear that fish oil supplements affect blood sugar long-term but Medline Plus recommends that diabetics consult a physician prior to taking a supplement.

Mercury and Fish Oil

Fish are a good source of omega-3 oils but some fish contain mercury, which can be dangerous for pregnant women and children. The Food and Drug Administration recommends that these populations avoid fish high in mercury but continue to eat up to 12 oz. of fish a week from low-mercury sources to benefit from omega-3 oils. Fish high in mercury include shark, mackerel, swordfish and tilefish. Omega-3 supplements from fish oil are safe and do not contain mercury, according to Medline Plus.
Other individuals who should not take fish oil supplements include those who are allergic or sensitive to fish. Rare side effects that have been reported with fish oil supplements are rash, abnormal liver function and psychological disorders.