Eicosapentaenoic acid (EPA) is one of several omega-3 fatty acids. It is found in cold-water fatty fish, such as salmon. It is also found in fish oil supplements, along with docosahexaenoic acid (DHA).

Omega-3 fatty acids are part of a healthy diet that helps lower risk of heart disease. Getting more EPA in your diet has positive effects on coronary heart disease, high triglycerides (fats in the blood), high blood pressure, and inflammation.

Most people in the Western world do not get enough omega-3 fatty acids in their diet.

Attention-Deficit Hyperactivity Disorder (ADHD)

Because children need omega-3 fatty acids for their brains to develop properly, researchers have looked at whether fish oil might reduce ADHD symptoms. So far, results have been mixed. One study showed fish oil might help, but many people dropped out of the study before it was done.

Depression

Some studies show that fish oil reduces symptoms of depression. Other studies suggest it may be a kind of EPA known as ethyl-EPA (and not DHA) that reduces symptoms.

Heart Disease

Fish oil seems to help people who already have heart disease. It also may lower the risk for developing heart disease. Omega-3 fatty acids found in fish oil help lower triglycerides and blood pressure, reduce the risk of blood clots, improve the health of arteries and reduce the amount of arterial plaque, which narrows arteries, and causes heart disease.

The American Heart Association (AHA) recommends eating fish, particularly fatty fish, at least 2 times a week. Fatty fish include salmon, herring, lake trout, sardines, and albacore tuna. People with existing heart disease may need fish oil supplements in addition to adding more fish to their diet. Ask your doctor if fish oil supplements would be right for you.

Rheumatoid Arthritis

Several small studies indicate that fish oil may help reduce symptoms and inflammation from rheumatoid arthritis. However, it does not stop joint damage from getting worse.

Menopause

One study found that EPA reduced the number of hot flashes by 1.58 per day in menopausal women. It did not decrease the severity of the hot flashes, however.

Menstrual Pain

Fish oil appears to reduce the pain of menstrual cramps when taken on a regular basis (not just when menstruating).

Raynaud Syndrome

Several studies show that high doses (12 g) of fish oil can make fingers and toes less sensitive to cold when people have Raynaud syndrome. Doses this high should be taken only under a doctor's supervision.

Lupus

Two small studies suggested that fish oil reduced fatigue and joint pain from lupus.

Other Conditions

Omega-3 fatty acids, including EPA, may also have positive effects on lung and kidney diseases, type 2 diabetes, obesity, ulcerative colitis, Crohn disease, anorexia nervosa, burns, osteoarthritis, osteoporosis, and early stages of colorectal cancer.

EPA is found in cold-water fatty fish, including salmon, tuna, mackerel, sardines, shellfish, and herring. Although some of these fish contain low levels of mercury, according to the Food and Drug Administration (FDA) eating several servings of fish each week poses no risk to healthy people and offers many health benefits.

Women who are pregnant or planning to become pregnant should avoid Atlantic mackerel, shark, swordfish, and tilefish, and eat less than 6 oz. of white albacore tuna per week. These fish tend to be higher in mercury.

High-quality fish oil supplements made by manufacturers who test for mercury and other toxins do not have the same risk of mercury contamination. Read labels carefully and check for purity, or ask your doctor to help you find the best quality fish oil supplement.

EPA is available in fish oil capsules, along with DHA (docosahexaenoic acid). Some commercial products may also contain vitamin E to maintain freshness.

Pediatric

• Babies who are breastfed should get enough EPA if their mother is getting enough EPA in her diet.

Adult

• The adequate daily intake of EPA for adults should be at least 220 mg per day.
• In the diet: 2 to 3 servings of fatty fish per week, which is the same as about 1,250 mg EPA and DHA per day.
• Fish oil supplements: 3,000 to 4,000 mg standardized fish oils per day. Read the label to check levels of DHA and EPA, which are not the same as mg of fish oil. People who take blood-thinning medication, such as warfarin (Coumadin), clopidogrel (Plavix), or aspirin, or people who have hemophilia, should ask their doctors what is a safe dose.

Some fish oil supplements also contain vitamin E for freshness. Check the label to see whether the product needs to be refrigerated. DO NOT use products beyond their expiration date.

Fish oil capsules have both DHA and EPA. DO NOT give supplements with EPA to a child unless your pediatrician tells you to because they upset the healthy balance between DHA and EPA during early development. Pregnant women should talk to their doctor before taking fish oil supplements.

Fish oil capsules may cause minor side effects, such as loose stools, stomach upset, and belching.

They also may raise the risk of bleeding. If you take blood-thinning medication, talk to your doctor before taking fish oil.

Blood pressure medication: Fish oil may lower blood pressure, so it could make the effects of prescription blood pressure medication stronger.

Blood-thinners (anticoagulants and antiplatelets): EPA in fish oil supplements may increase bleeding time, so fish oil could make these drugs act stronger. The same does not seem to be true of DHA alone. Blood thinners include warfarin (Coumadin), clopidogrel (Plavix), and aspirin.

Diabetes medications: Theoretically, fish oil supplements may lower blood sugar levels and could make diabetes drugs act stronger. If you have diabetes, talk to your doctor before taking fish oil.

Aspirin: Taken with aspirin, fish oil may help treat some forms of heart disease. However, this combination may also increase the risk of bleeding. Talk to your doctor to see if this combination is right for you.

Cyclosporine: Omega-3 fatty acids may reduce some of the side effects of cyclosporine, which is often used to stop rejection in transplant recipients. Talk to your doctor before adding any new herbs or supplements to the medication you already take.

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