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Benefits Far Outweigh the Risks of Eating Fish

Seafood is a smart choice for health-conscious consumers. It’s a lean protein that delivers a host of health benefits through omega-3s, the super-polyunsaturated fats found in fish oil. Ounce for ounce, fish and shellfish generally are lower in saturated fat than other meat proteins (only chicken breast is lower), and fewer of the calories in seafood are from fat (see Figure 1). 

Most seafood is also low in cholesterol, another big concern for those trying to maintain a healthy diet. Cholesterol on its own is not a big threat unless high levels appear in foods that are also high in saturated fat. Even seafood items with relatively high cholesterol levels, such as shrimp, at 152 milligrams per 3.5-ounce serving, have very low levels of saturated fat. Atlantic salmon, high in saturated fat as seafood goes, still comes in under other proteins and provides a whopping 1.9 grams of beneficial omega-3s. 

Omega-3s are a class of fatty acids essential to health, but the human body can’t manufacture them; they must be obtained from the oils in certain foods, including fish, nuts and plants, such as soybeans and flax. Also called PUFAs, these polyunsaturated fatty acids aid many of the body’s functions, and they have been found also to protect against heart disease and stroke, certain types of cancers and neurological disorders, among a host of other benefits (see below). 

Fish contain two types of omega- 3s, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that provide the greatest health benefits. Oil-rich fish like salmon, mackerel and herring have the highest levels of omega-3s (see Figure 2). Lean white-fleshed fish like haddock and flounder contain lower amounts of the fatty acids, as do most shellfish. 

The connection between omega- 3s and heart health was first made in the 1970s by Scandinavian researchers who found a low incidence of heart disease among Greenland’s Inuits, whose diet was rich in seafood. Since then, there’s been a tremendous amount of research associating omega-3s with reduced risk of cardiovascular disease. 

In 2000, the American Heart Association recommended that healthy adults eat fish, particularly fatty fish, at least twice a week. 

The brain may also benefit from regular seafood consumption. For example, eating fish during pregnancy appears to aid fetal brain development, according to a Harvard Medical School study. 

Along with all the good news about the health benefits of eating seafood came ominous reports about the dangers of eating fish containing methylmercury, a neurotoxin known to harm fetal brain development. Methylmercury is highly concentrated in long-lived, predatory fish. A 2004 advisory from the U.S. Food and Drug Administration and Environmental Protection Agency urged pregnant and nursing women, women of childbearing age and young children to avoid eating shark, tilefish, swordfish and king mackerel and limit canned albacore-tuna consumption to 6 ounces per week.

The piece that gets lost amid the warnings is that methylmercury is a hazard only to the segments of the population addressed by the advisory, and the U.S. Department of Agriculture still urges this group to eat up to 12 ounces (two to four servings) a week of a variety of seafood. 

For consumers not in the advisory group, the nutritional benefits of eating seafood far outweigh risks from methylmercury. A study by the Harvard Center for Risk Analysis found that if consumers cut seafood consumption by just one-sixth, the risk of developing cardiovascular disease would increase. And the loss of omega-3s during pregnancy would reduce an infant’s nutritional benefit by 80 percent. 

Further, more recent research shows that selenium protects against methylmercury exposure. Of the 25 foods that contain high levels of selenium, 16 are ocean fish, says the U.S. Department of Agriculture. 

Selenium and methylmercury are measured in moles, the number of atoms in a given amount of matter. Most fish on the market contain 5 to 20 moles of selenium for every mole of methylmercury, and one mole of selenium can protect against 75 moles of methylmercury, found the University of North Dakota’s Energy and Environmental Research Center. 

That is the sort of information consumers need to allay their concerns about eating seafood. The nutritional benefits this lean, PUFA-rich protein offers far outweigh the risks.