What are fish oil supplements?
Fish oil supplements are dietary supplements that contain oil from cold water fish such as mackerel, salmon, black cod, albacore tuna, sardines, and herring. The active ingredients in fish oil supplements are essential fatty acids known as omega-3 fatty acids. They typically include eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
Fish oil uses
Although fish oil supplements have been used to treat conditions including arthritis, colitis, and other diseases, the most reliable information about them has been collected on their effects in people with high cholesterol and heart disease. Medical research shows that eating one gram of fish oil daily can reduce the risk of heart attack and stroke in people who have heart disease. Research suggests it may also have protective effects on otherwise healthy people.
Fish oil has been reported to increase HDL cholesterol (a "good" form of cholesterol) and lower the amount of triglycerides, or dissolved fat, in the blood. But, it can increase LDL cholesterol, a harmful form of cholesterol. Since many people who have high triglycerides also have high LDL cholesterol, fish oil supplements are not a good choice without knowing your health status. You should not substitute fish oil supplements for prescription medicines without first discussing this with your doctor.
Choosing a fish oil supplement
You can choose fish oil supplements based on their active ingredients. Since most of the
medical research about fish oil has used products that contain both EPA and DHA, it's a good
idea to choose a fish oil product that contains both. It is not a good idea to use cod liver
oil as a fish oil supplement because it contains very high levels of vitamin A. High doses of
vitamin A can cause headache, dry skin, itching, and liver damage.
The dose of fish oil required to reduce triglycerides in the bloodstream is five to twenty grams (or 5,000 to 20,000 mg) a day. You will see a greater risk for side effects at the higher dosages.
Side effects of fish oil
The most commonly reported side effects of fish oil supplements include fishy odor on the breath, upset stomach, and greasy stools. A more serious side effect can be an increase in LDL cholesterol, a harmful form of cholesterol. Large doses of fish oil supplements may also cause weight gain and decrease the absorption of vitamins A, E, D, and K from the stomach. If you have diabetes, use caution when taking fish oil supplements, they are reported to increase blood sugar.
Dangers of overdose and cod liver oil
Taking large amounts of fish oil supplements over a long period of time may increase the risk of mild bleeding resulting in nosebleeds and bruising. It's not a good idea to use cod liver oil as a fish oil supplement because it contains very high levels of vitamin A. High doses of vitamin A can cause headache, dry skin, itching, and liver damage.
Back to Ask a Pharmacist