Eating fatty fish such as salmon, tuna, or mackerel at least once a week may help prevent heart attacks and other serious cardiovascular problems. That’s according to a recent scientific advisory from the American Heart Association, which reaffirms a long-held observation about the health benefits of seafood.

You’ll potentially reel in the biggest benefit if you replace less healthy foods — such as red meat or processed meats — with seafood entrees. For example, choose salmon over steak, and swap the ham on your sandwich for tuna.

“Eating two servings of fatty fish per week, which averages out to about 250 milligrams of omega-3 fatty acids a day, has been linked to a lower risk of heart attack and other cardiac issues,” says Harvard Medical School professor Dr. Bruce Bistrian, who is chief of clinical nutrition at Beth Israel Deaconess Medical Center. Some of this benefit appears to come from the cardioprotective effects of omega-3 fatty acids, he explains.

The dish on fish

happy senior man eating grilled fish outside on restaurant terrace

Found mainly in fish, these fats include eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Omega-3s appear to help ease inflammation, prevent the formation of dangerous blood clots, and discourage potentially deadly heart arrhythmias.

Population-based studies suggest that people who eat fatty fish are half as likely as people who don’t eat fish to experience cardiac arrest (when an irregular heart rhythm causes the heart to suddenly stop beating). Fish eaters also appear to have a 22% lower risk of coronary artery disease (clogged arteries in the heart). But there’s a threshold effect at play, says Dr. Bistrian. That is, eating more than two servings a week does not appear to further lower the risk of heart problems. The best choices appear to be those highest in omega-3 fatty acids (see “Omega-3 fatty acids in seafood”). But other varieties of fish are still good sources of lean protein — as long as they’re not deep-fried.

Some of the heart advantages seen in people who eat fish may stem from the fact that they’re not eating beef, pork, or other foods that contain saturated and trans fats, says Dr. Bistrian. These foods tend to increase chronic inflammation, a bodywide process that ignites the accumulation of fatty plaque in the arteries (atherosclerosis).

Omega-3 fatty acids in seafood

Americans eat an average of 1.3 servings of seafood per week. The most popular choices are shrimp, salmon, canned tuna, tilapia, and pollock. The American Heart Association recommends eating a wide variety of fish, including types rich in the omega-3 fatty acids DHA and EPA.
Type of seafood Milligrams DHA and EPA per 4 ounces
Salmon (Atlantic, chinook, coho) 1,200–2,400
Mackerel (Atlantic, Pacific) 1,350–2,100
Sardines (Atlantic, Pacific) 1,100–1,600
Swordfish 1,000
Tuna (albacore, canned) 1,000
Pollock (Atlantic, walleye) 600
Cod (Atlantic, Pacific) 200
Tilapia 150
Crab (blue, king, queen, Dungeness) 100
Shrimp 100
Source: Circulation, July 3, 2018, e35-e47.

Healthy fats from plants

Fish is also featured in the Mediterranean diet, an eating pattern recommended by the Dietary Guidelines for Americans. But what if you don’t care for fish, or you avoid all types of meat (vegetarian) or all animal-based foods (vegan)?

Many plants, including seeds, nuts, and some green vegetables, include an essential fatty acid called alpha-linolenic acid (ALA). Good sources include flaxseed, walnuts, pumpkin seeds, and soybean or canola oil. Your body can convert a small amount — about 7% to 10% — of your dietary ALA to EPA. Research suggests that because of genetic variations, some people seem to convert ALA to EPA more efficiently than others.

If you eat a healthy vegetarian diet with plenty of ALA-rich foods, you’ll probably get close to the same amount of EPA as a person who eats fish twice a week, says Dr. Bistrian. In any case, vegetarians and vegans tend to have lower rates of cardiovascular disease than omnivores.

Fish oil supplements (also sold as EPA and DHA supplements) are enormously popular. But there’s limited evidence they help improve outcomes in people without known heart disease, according to an American Heart Association advisory issued in 2017. However, if you’ve already experienced a heart attack, taking about 1,000 milligrams of EPA and DHA a day might cut your risk of sudden cardiac death by about 10%, though definitive studies are ongoing. The supplements might also lower death and hospitalization rates among people with heart failure, but more study is needed here too. So don’t take fish oil supplements except under the advice of a physician.

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