Flaxseed oil and fish oil are two different supplements that contain a type of unsaturated fat known as omega-3 fatty acids. These supplements are often used to reduce patients' risk of developing cardiovascular problems, but they may also be used to reduce inflammation. These two supplements have similar mechanisms and, if taken in large doses, lead to potentially serious side effects.
Omega-3 Fatty Acids
Omega-3 fatty acids are unsaturated fats that cannot be synthesized by the body. Consequently, these "essential" amino acids must be consumed either from the diet or from supplements. These fats, the University of Maryland Medical Center notes, are critical for proper nerve function, which is why they are sometimes used to treat psychiatric disorders such as anxiety, schizophrenia, bipolar disorder and attention-deficit hyperactive disorder. Omega-3 fatty acids also are recommended for people who have diseases caused by excessive inflammation or who have an increased risk of having a heart attack.
Fish oil is one of the most commonly used omega-3 fatty acid supplements. Fish oil contains two different omega-3 fatty acids, known as EPA and DHA or eicosapentaenoic acid and docosahexaenoic acid. According to the National Institutes of Health fish oil can lower your triglyceride levels and possibly lower your blood pressure, while also making it harder for platelets to form blood clots. Consequently, people consuming fish oil are less likely to have a heart attack. Fish oil may also be used to treat diseases mediated by excessive inflammation, such as Crohn's disease and asthma, though more research still needs to be done on the effectiveness of fish oil for these conditions.
Flaxseed oil consists of between 50 to 60 percent of the omega-3 fatty acid alpha-linoleic acid, the University of Maryland Medical Center states. Despite its high levels of omega-3 fatty acids, flaxseed oil does not seem to be as effective at treating health problems because alpha-linoleic acid needs to be converted into EPA or DHA to be active in the body. Although this process is not particularly efficient, flaxseed oil may help lower cholesterol, prevent heart attacks and relieve symptoms of Sjogren's syndrome, an autoimmune condition that affects the eye.
Risks of Fish Oil and Flaxseed Oil
Although both flaxseed oil and fish oil are generally safe for people to use, taking both of these supplements can cause potentially serious side effects. EPA and DHA make it hard for platelets to stick together and form blood clots. Although this reduces your risk of having a heart attack, too much EPA and DHA can cause your blood to become too thin, increasing your risk of bruising or bleeding easily and increase your risk of stroke, according to the November 2009 issue of "Nutrition Research." If you want to take both of these supplements, talk to your doctor; blood tests that measure clotting ability can help determine if your blood is becoming too thin.