ARE FISH FRIEND OR FOE? Fears of contaminants make many shy away from seafood--unnecessarily.

• Author: Feldscher, Karen
• Position: NUTRITION IN A NUTSHELL

FISH IS A VERY important part of a healthy diet. Fish and other seafood are the major sources of healthful long-chain omega-3 fats and also are rich in other nutrients (such as vitamin D and selenium), high in protein, and low in saturated fat. There is strong evidence that eating fish or taking fish oil is good for the heart and blood vessels. An analysis of 20 studies involving hundreds of thousands of participants indicates that eating approximately one to two three-ounce servings of fatty fish a week--salmon, herring, mackerel, anchovies, or sardines--reduces the risk of dying from heart disease by 36%.

Eating fish fights heart disease in several ways. The omega-3 fats protect the heart against the development of erratic and potentially deadly cardiac rhythm disturbances. They also lower blood pressure and heart rate, improve blood vessel function, and, at higher doses, lower triglycerides and may ease inflammation. The strong and consistent evidence for benefits is such that the Dietary Guidelines for Americans, the American Heart Association, and others suggest that everyone eat fish twice a week.

However, fewer than one in five Americans heeds that advice. About one-third eat seafood once a week, while nearly half eat fish only occasionally or not at all. Although some people simply may not like fish, the generally low consumption likely is due to other factors as well, including perceptions about cost, access to stores that sell fish, and uncertainty about how to prepare or cook fish.

Still others may avoid seafood because they worry that they--or their children--will be harmed by mercury, pesticide residues, or other possible toxins that are in some types of fish. Should you forgo fish because of the contaminants they might carry? It is a controversial topic that often is fueled more by emotion than fact.

In a comprehensive analysis of human studies, Harvard School of Public Health professors Dariush Mozaffarian and Eric Rimm calculated that eating about two grams per week of omega-3 fatty acids in fish, equal to about one or two servings of fatty fish a week, reduces the chances of dying from heart disease by more than one-third. Both observational studies and controlled trials also have demonstrated that the omega-3 fats in fish are important for optimal development of a baby's brain and nervous system, and that the children of women who consume lower amounts of fish or omega-3s during pregnancy and breast feeding have evidence...