Fish: The Fountain of Youth?

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Salmon steak on a plate

Eating fish can be good for the heart and even for the brain, so it’s probably no surprise that pelagic products can lead to a longer life.

Omega-3 fatty acids have long been credited with protecting the heart and reducing risk of heart attack and stroke, but studies on the benefits of supplementing with fish oils have had conflicting results. So researchers from the Harvard School of Public Health and the University of Washington decided to explore whether fish oil’s benefits for the heart translated into longer life spans.

The researchers combed through 16 years of data on 2,700 healthy adults ages 65 and up who were not taking fish-oil supplements and participated in the long-term Cardiovascular Health Study from the National Heart, Lung and Blood Institute. Throughout the 16 years, the participants had physical exams, took diagnostic tests, submitted blood samples and answered questionnaires about their health, lifestyle and medical history.

(MORE: Study: Eating Omega-3s May Help Reduce Alzheimer’s Risk)

From the blood samples, the researchers isolated docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA), the healthy fatty acids found in fish oils, that served as a proxy for how much fish the participants ate.

Reporting in the Annals of Internal Medicine, the researchers found that those with higher levels of all three fatty acids showed a 35% lower risk of dying of heart disease compared with those with lower levels of the fats in their blood. DHA was associated with a 40% lower risk of coronary-heart-disease death, in which gradual buildup of plaque within the heart-vessel walls can lead to heart failure, often from irregular heart beats. EPA was linked to a lower risk of heart attacks, and DPA was associated with a lower risk of death from stroke. When the researchers factored in not just heart disease but other causes of death, those with the highest levels of all three fatty acids were 27% less likely to die during the study period and lived on average more than two years longer than those with the lowest levels.

Although the heart benefits of omega-3s have long been established, researchers say little is known about how they influence longevity, and these results highlight how beneficial the omega-3 fatty acids can be. Even more encouraging, the greatest benefit from omega-3-fatty-acid levels occurred among participants who started out eating very few fish and increased their intake to about 400 mg daily. This equates to consuming about two servings per week, which is what the latest Dietary Guidelines for Americans and the American Heart Association recommends.

(MORE: Omega-3s as Study Aid? DHA May Help Lowest-Scoring Readers Improve)

One serving is about 3.5 oz. of cooked or a ¾ cup of flaked fish. Fish with the highest amount of omega-3 fatty acids include salmon, mackerel, herring, lake trout, sardines and albacore tuna. However, these fish can also be high in mercury, which is a toxin that can interfere with brain development and hamper kidney and nervous-system function. Young children and pregnant women should avoid fish that may contain higher levels of the metal such as shark, swordfish, king mackerel or tilefish.

For most people, however, the benefits of eating more fish, for the heart and the body, may provide them with the ultimate reward — a longer, and hopefully healthier, life.