Omega-3 in fish: How eating fish helps your heart

The omega-3 fatty acids in fish are good for your heart. Find out why the heart-healthy benefits of eating fish usually outweigh any risks. By Mayo Clinic Staff

If you're worried about heart disease, eating one to two servings of fish a week could reduce your risk of dying of a heart attack.

For many years, the American Heart Association has recommended that people eat fish rich in omega-3 fatty acids at least twice a week. Doctors have long believed that the unsaturated fats in fish, called omega-3 fatty acids, are the nutrients that reduce the risk of dying of heart disease. However, more recent research suggests that other nutrients in fish or a combination of omega-3 fatty acids and other nutrients in fish may actually be responsible for the health benefits from fish.

Some people are concerned that mercury or other contaminants in fish may outweigh its heart-healthy benefits. However, when it comes to a healthier heart, the benefits of eating fish usually outweigh the possible risks of exposure to contaminants. Find out how to balance these concerns with adding a healthy amount of fish to your diet.

What are omega-3 fatty acids, and why are they good for your heart?

Fish contain unsaturated fatty acids, which, when substituted for saturated fatty acids such as those in meat, may lower your cholesterol. But the main beneficial nutrient appears to be omega-3 fatty acids in fatty fish. Omega-3 fatty acids are a type of unsaturated fatty acid that may reduce inflammation throughout the body. Inflammation in the body can damage your blood vessels and lead to heart disease.

Omega-3 fatty acids may decrease triglycerides, lower blood pressure, reduce blood clotting, decrease stroke and heart failure risk, reduce irregular heartbeats, and in children may improve learning ability. Eating at least one to two servings a week of fish, particularly fish that's rich in omega-3 fatty acids, appears to reduce the risk of heart disease, particularly sudden cardiac death.

Does it matter what kind of fish you eat?

Fatty fish, such as salmon, lake trout, herring, sardines and tuna, contain the most omega-3 fatty acids and therefore the most benefit, but many types of seafood contain small amounts of omega-3 fatty acids.

Are there any kinds of fish you should avoid?

Some fish, such as tilapia and catfish, don't appear to be as heart healthy because they contain higher levels of unhealthy fatty acids. Keep in mind that any fish can be unhealthy depending on how it's prepared. For example, broiling or baking fish is a healthier option than is deep-frying.

Some researchers are concerned about eating fish produced on farms as opposed to wild-caught fish. Researchers think antibiotics, pesticides and other chemicals used in raising farmed fish may cause harmful effects to people who eat the fish.

How much fish should you eat?

For adults, at least two servings of omega-3-rich fish a week are recommended. A serving size is 3.5 ounces (99 grams), or about the size of a deck of cards. Women who are pregnant or plan to become pregnant and young children should limit the amount of fish they eat because they're most susceptible to the potential effects of toxins in fish.

Feb. 07, 2014 See more In-depth