Nutrition Column – Fish as Part of a Healthy Diet: More Benefits Than Risks

Fish and other seafoods long have been considered to be good sources of protein, zinc and iron, with the added advantage of being low in saturated fat and high in healthy omega-3 fatty acids. Research shows that omega-3 fatty acids help make blood less "sticky" and therefore less likely to form the clots that can contribute to heart disease. In addition, omega-3 fatty acids contribute to proper brain development of fetuses and infants, help lower blood pressure and can lower the risk of stroke.

In recent years, however, reports about contamination of some fish with methylmercury have raised concerns about the healthfulness of fish for some populations. Mercury is a metallic substance that occurs naturally in the environment. It also can be released into the air through industrial pollution. When mercury falls from the air, it gets into surface water, accumulating in streams and oceans. Bacteria in the water cause chemical changes that transform mercury into methylmercury that can be toxic, particularly to developing bodies. Fish absorb methylmercury from water as they feed on aquatic organisms.

Nearly all fish contain trace amounts of methylmercury, but at levels that are not harmful to humans. It is only the long-lived, larger fish that feed on other fish that accumulate enough methylmercury to be considered potentially harmful, and then only to the developing nervous systems of a pregnant woman’s unborn child.

Because of these concerns, the Food and Drug Administration recommends that pregnant women, women who may become pregnant and children under the age of six avoid eating shark, swordfish, king mackerel and tilefish, all of which are fish that can have high levels of mercury, or to limit consumption to once a month. All other fish are safe for pregnant women to eat, but as a measure of prudence, the FDA recommends that pregnant women consume a variety of types of fish and average no more than 12 ounces of fish per week. Given that the typical serving of fish is from 3 ounces to 6 ounces, we’re still talking about two to three servings of fish per week, even for pregnant women, the group advised to moderate their consumption of fish.

Fatty fish such as salmon, tuna, trout, sardines and halibut have the highest amounts of omega-3 fatty acids. The American Dietetic Association recommends eating fish two to three times per week to gain the health benefits. If you know you should be eating more fish but are having trouble incorporating it into your diet, here are some tips to help you get started:  

– Add seafood gradually. Try substituting fish for one meat meal per week.

– Cook fish properly. For best results, use high temperature and a short cooking time. A good basic rule is 10 minutes per inch of thickness at 450 degrees.

– Cook fish to an internal temperature of 145 degrees F, or until it flakes easily with a fork.

– Water-packed canned fish and frozen fish are just as healthy as fresh and provide a convenient and often less-expensive option.

– Add fish or seafood to recipes that normally require beef or chicken.

– Don’t limit consumption to only one type of fish. Try a variety to gain as much nutritional benefit as possible.

by Pat Kendall, Ph.D., R.D., Food Science and Human Nutrition Specialist, Colorado State University, Cooperative Extension