A: You're right about the controversy of eating fish. We know that it is an excellent source of protein and nutrients and contains omega-3 fatty acids, which contribute to healthy fetal and infant development and may reduce the risk of heart disease. However, certain fish contain high levels of contaminants, including mercury and polychlorinated biphenyls (PCBs).

All fish contain some level of pollutants; larger ocean fish accumulate high levels of mercury, which is stored in its muscle. Mercury has been shown to be harmful for neural development during pregnancy and childhood. Fish with higher levels of mercury include shark, swordfish, king mackerel, tilefish and fresh or frozen tuna. These fish should be avoided, or eaten only occasionally, no more than once or twice a month.

PCBs are organic pollutants that have been linked to developmental problems in humans and cancer in animals. PCBs collect in the fatty portion of fish, and are found in fish all over the world. Recent research showed that farmed salmon contains higher levels of PCBs than wild salmon, and should be avoided.

It is safest to consume a variety of fish, and limit your intake to one or two times a week. Minimize your consumption of fish with more fatty flesh, such as catfish, bluefish and striped bass. If you like to catch and prepare your own fish, check local advisories about the safety of varieties in your region. Wild salmon, which includes canned salmon, may be safer than farmed salmon, although salmon farmers are working to reduce the levels of contaminants in their fish. Other safer choices include flounder, Pacific cod, mahi-mahi, haddock, sole, sardines and most shellfish.

Additionally, the way you prepare fish can influence your amount of exposure to contaminants. Remove the skin and trim away fatty parts before cooking. Avoid frying, breading or cooking in batter. You can poach, grill or use an elevated rack to bake or broil your fish. This allows the fats to drain off, making it a healthier choice for you and your family. With proper care to eat limited amounts of the safer varieties, you will be able to enjoy the benefits of eating fish.