Medical experts are almost unanimous in believing that seafood belongs in a healthy diet.

It is a rich source of high-quality protein and fat-soluble vitamins such as A, D, and E. Fish is also the only common source of another essential nutrient: omega-3 fatty acids.

Omega-3s are especially important for pregnant and nursing women, and promote the development of fetuses, infants, and young children. In people of all ages, omega-3s help boost immunity and reduce the risk of heart disease, brain aging, stroke, cancer and other conditions.

Unfortunately, many fish also contain contaminants that can lead to serious health problems. Mercury is the most common, but industrial chemicals such as PCBs, dioxins, and pesticides are also in many species of fish.

Mercury is a powerful brain toxin. It can interfere with thinking, learning, and problem-solving. In some cases it can cause irreversible neurological damage.

The most common source of mercury poisoning is eating fish that contains the heavy metal.

Despite such concerns, the preponderance of evidence shows that the benefits of eating seafood far outweigh the potential risks, such as mercury toxicity. For example, a 2006 study showed that modest fish consumption (1-2 servings per week, especially of oily fish rich in omega-3s) reduces the risk of coronary death by 36 percent, and death from any cause by 17 percent and is associated with minimal risks.

This means that it is crucial to make right choice when eating seafood.

Here are 10 species low in mercury according to the Natural Resources Defense Council, yet with plenty of healthy omega-3s:


Best Fish

1. Salmon (canned and fresh)
2. Anchovies
3. Herring
4. Sardines
5. Freshwater trout
6. Flounder
7. Atlantic mackerel
8. Whitefish
9. Catfish
10. Ocean perch

Worst Fish

These fish are among the highest in mercury content and should seldom be eaten, even though some of them are high in omega-3s. Pregnant women should never eat these fish.

1. King mackerel
2. Orange roughy
3. Shark
4. Swordfish
5. Tilefish
6. Bigeye tuna
7. Ahi tuna
8. Marlin

Know Your Salmon

It should be noted that although both farmed and wild fresh salmon are considered excellent choices, some farmed salmon, depending on the source, can be contaminated with PCBs, antibiotics, and other harmful substances.

U.S. Atlantic salmon is usually a safe source for farmed fish. Avoid imported farmed salmon, which often comes from Chile, Norway, or Canada. Chilean fish farms, in particular, have been known to be raised in polluted waters and to be dosed with high levels of antibiotics.