Fish Oil Complications

The Food and Drug Administration (FDA) says, "Supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease." Omega-3 fatty acids are concentrated in fish oil and can benefit the heart, diabetes, lupus, osteoporosis, depression, psychological disorders, skin conditions, vision, asthma and certain cancers. The University of Maryland Medical Center (UMMC) recommends only taking fish oil supplements under the supervision of a medical professional because of possible side effects and medication interactions.

Bleeding

Medline Plus, a service of the National Institutes of Health (NIH), says omega-3 fatty acids increase the risk of bleeding and have been associated with nose bleeds and bloody urine. The UMMC advises individuals with bleeding disorders to be cautious when taking omega-3 supplements. Omega-3 fish oil supplements can also interact with Coumadin (warfarin), a blood-thinning medication.

Intestinal Discomfort

The American Heart Association (AHA) printed an article in "Circulation" in 2003 that listed intestinal discomfort, nausea and bad aftertaste as the most common side effects of omega-3 fish oil supplements. Other side effects of omega-3 supplements include diarrhea, burping, acid reflux, heartburn, bloating and abdominal pain. Medline Plus says side effects of omega-3 supplements can be minimized by taking supplements with meals and starting with a low dose that gradually increases.

Hypotension

Hypotension is low blood pressure and according to Medline Plus, multiple studies have associated omega-3 supplements with hypotension. This may benefit individuals with high blood pressure but may be dangerous for people with existing hypotension or those taking medications to lower blood pressure.

High Blood Sugar

According to the UMMC, omega-3 fish oil supplements can increase blood sugar and interact with diabetic medications that lower blood sugar. Medline Plus says supplements may not have long-term effects on blood sugar but advises diabetics to consult a physician prior to supplementing with fish oil.

Allergy and Mercury Contamination

Individuals with allergies or sensitivities to fish should not take fish oil supplements, according to Medline Plus. Certain fish such as shark, tilefish, mackerel and swordfish contain mercury contaminants that can be dangerous for pregnant women and children. The FDA advises these populations to benefit from omega-3 fatty acids by eating fish low in mercury such as canned tuna, salmon and halibut. According to the UMMC, fish oil supplements do not contain mercury but individuals should still buy fish oil supplements from reputable sources to ensure their safety.