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The Benefits of Fish and Seafood for Your Heart

Content provided by the Faculty of the Harvard Medical School

How much to eat

At least two servings per week, including at least one serving of oily (dark meat) fish.

Serving size

3–4 ounces.

The evidence. In the 1970s, scientists noted that Greenland Eskimos, who subsisted largely on fish, had a low rate of heart disease. This finding led to research on the benefits of fish and the discovery of omega-3 fats — polyunsaturated fats that are particularly heart-healthy.

For example, an analysis of data from 11 studies tracking a total of 222,364 people found the risk of death from coronary artery disease fell as fish consumption increased. Eating fish a few times a month reduced risk by 11%, two to four times a week by 23%, and five or more times a week by 38%.

Other research has documented a 36% lower risk of dying from heart disease in people who consume about 250 milligrams per day of the omega-3 fats called EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) from fish, compared with those who eat no fish.

According to a 2011 Circulation paper, studies have shown that fish oil lowers many risk factors for heart disease, including triglyceride levels and blood pressure. It might also decrease inflammation. If you have heart disease or are at risk for developing it, consider eating fish even more often, or talk to your doctor about taking fish oil supplements.

What about contaminants such as mercury, found in certain types of fish? A study conducted by the Harvard School of Public Health determined that for all adults, the benefits of modest fish intake — one to two servings per week — exceed the potential risks from mercury or other contaminants. Consistent with this, a second large study found that in both men and women, people with higher exposure to mercury had no increased risk of heart disease or stroke. Women who are or might become pregnant should avoid eating larger, long-lived fish like swordfish, shark, golden bass, and king mackerel, which have a higher concentration of mercury. For everyone else, simply eat a variety of different fish species.

Why they help the heart. Oily, cold-water fish, such as salmon, herring, sardines, and tuna, contain EPA and DHA. These fats reduce the risk of fatal heart attacks and sudden cardiac death caused by electrical problems in the heart. Eating fish may reduce the risk of stroke as well. Fish also contain vitamin D, specific healthful proteins, selenium, and other nutrients.

Practical tip: Choosing seafood. With the exception of commercially fried fish sticks and burgers, eating any fish or shellfish is likely to provide heart benefits, compared with eating none. All else being equal, fish and shellfish that contain higher levels of omega-3 fatty acids are likely to provide more benefit. For the average adult, the best advice is to eat a variety of different fish and shellfish, at least two servings each week, with at least one of these being an oily or dark meat fish. See the chart below for the best choices.

Good sources of omega-3 fatty acids

Food

Milligrams (mg) omega-3s per serving
(3.5 oz or about ½ cup)

Anchovy

2,050

Herring, Atlantic

2,000

Salmon, farmed

1,950

Salmon, wild*

1,850

Mackerel, Atlantic

1,200

Sardines, Atlantic

1,000

Bluefish

1,000

Trout

900

Tuna, white, albacore

850

Mussels

800

Bass, striped

750

Oysters, wild

500

Tuna, light

300

Halibut

200

Eggs

50 per egg (may vary, check label)

*Amounts vary by different species of wild salmon, such as King, Silver, or Pink; this is the average.

Last Annual Review Date: 2011-10-01 Copyright: © 2011 Harvard Health Publications

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