The word fish has entered the American vocabulary in several not so savory ways. ``That's a fish tale,'' for example, and ``That smells fishy,'' suggest a highly exaggerated story, blatant lie or misdeed.
But in the last two decades, fish and shellfish have enjoyed more positive press, lauded for conveying a number of important health benefits to those who dine on them.
Indeed, the new image of fish has sparked all manner of creativity, with fish and shellfish starring on platters, napkin rings, glassware, jewelry, clothing and even carpets.
Sadly, this popularity of fish as an artistic form has not translated into any drastic transformation in American dining habits. Seafood hardly holds its own next to meat and poultry as a source of animal protein, and the industry says annual consumption peaked in 1987 at 16.2 pounds per person, falling just below 14.8 pounds in 2001.
Evidence suggests that eating just two fish meals a week--two 3-ounce servings--can make a significant difference in the risk of developing ills like heart attacks and strokes.
Part of the benefit may come simply from eating fish in place of red meat, a supposed culprit in cardiovascular disease. But another more important part, the evidence suggests, involves the fats found in fish, namely omega-3 fatty acids, which may have a physiological role in preventing cardiovascular disease.
Benefits of fish
But as with most worthwhile things in life, with fish and shellfish, there's no free lunch. Risks as well as benefits attend eating seafood, although a wise and well-informed consumer can certainly tip the balance well in favor of the benefits.
For fish to maintain fluidity in cold water, their fats have to remain liquid, and liquid fats (really oils) are polyunsaturated. But fish oils, rich in omega-3 fatty acids, are chemically different from the polyunsaturated oils in plants like corn and soybeans, and it is that difference that has given fish star billing.
They can inhibit the synthesis of substances that promote inflammation, reduce the tendency of the blood to form clots, stabilize the electrical activity of the heart, lower triglyceride levels, reduce blood pressure moderately and improve the functioning of artery linings.
Most, but not all, studies have found that people who eat fish regularly experience significant reductions in the risk of heart attacks, strokes and deaths from all causes.
Other suggested benefits include an anti-inflammatory effect that can help people with autoimmune diseases like rheumatoid arthritis, psoriasis and ulcerative colitis.
Health risks
Some fish are contaminated with mercury and other toxic substances introduced as industrial pollutants into their waters.
Mercury is a well-known neurologic and kidney toxin that is best not ingested. The fish most likely to be contaminated are large deep-sea species like swordfish, king mackerel, shark and tilefish and are best avoided, especially by pregnant women.
Fish, especially shellfish, can also become contaminated by harmful micro-organisms that occur naturally and those that result from sewage pollution.
But it is raw fish, especially raw shellfish, that is the most common source of food poisoning. Only ocean-dwelling fish should be used in sushi, sashimi and seviche.
The filter-feeders-—clams, oysters and other mollusks like mussels and scallops--can accumulate waterborne bacteria, viruses or toxins that can cause severe gastrointestinal problems when the shellfish is eaten uncooked.
Crustaceans like shrimp and lobster should never be eaten raw, and all mollusks that are should have been harvested from certified beds. The safest bet, however, is to cook them.