Benefits
Protects against stroke: A study found that people who ate fish at least once a week were 13 per cent less likely to suffer from a blockage of the blood supply to the brain (ischemicstroke) than those who did not eat fish that often. Now the American Heart Association recommends eating fish at least two times a week because the omega-3 fatty acids help protect the heart.
Helps fight disease: Fatty fish are the richest source of omega-3 fats. Omega-3s are critical for cardiovascular health and may also help protect against arthritis, diabetes, depression, and some cancers. Omega-3s are most concentrated in cold-water fatty fish such as sardines, herring, salmon, mackerel, and trout.
Risks
Dangerous during pregnancy: Pregnant women, nursing mothers, and women considering pregnancy should limit exposure to fish containing methylmercury — the form of mercury that is found in fish. This industrial pollutant can impede the development of the nervous system in fetuses, babies and young children. Since methylmercury tends to accumulate over time, it is most concentrated in larger fish with longer life spans, such as shark, swordfish, king mackerel, tilefish, and albacore tuna.
Farmed fish may contain contaminants: Farmed salmon may contain high levels of pesticides and other toxins. To avoid any negative effects of this contamination, make it a point to buy wild salmon instead of farmed salmon. When grocery shopping, look for the labels on salmon to identify the fish as either farmed or wild.