The New Complete Book of Food
moisture it will lose. Cooked fish flakes because the connective tissue in fish “melts” at a
relatively low temperature.
Heating fish thoroughly destroys parasites and microorganisms that live in raw fish,
making the fish safer to eat.How Other Kinds of Processing Affect This Food
Marinating. Like heat, acids coagulate the proteins in fish, squeezing out moisture. Fish
marinated in citrus juices and other acids such as vinegar or wine has a firm texture and
looks cooked, but the acid bath may not inactivate parasites in the fish.
Canning. Fish is naturally low in sodium, but canned fish often contains enough added
salt to make it a high-sodium food. A 3.5-ounce serving of baked, fresh red salmon, for
example, has 55 mg sodium, while an equal serving of regular canned salmon has 443 mg.
If the fish is canned in oil it is also much higher in calories than fresh fish.
Freezing. When fish is frozen, ice crystals form in the flesh and tear its cells so that mois-
ture leaks out when the fish is defrosted. Commercial flash-freezing offers some protec-
tion by freezing the fish so fast that the ice crystals stay small and do less damage, but all
defrosted fish tastes drier and less palatable than fresh fish. Freezing slows but does not
stop the oxidation of fats that causes fish to deteriorate.
Curing. Fish can be cured (preserved) by smoking, drying, salting, or pickling, all of which
coagulate the muscle tissue and prevent microorganisms from growing. Each method has
its own particular drawbacks. Smoking adds potentially carcinogenic chemicals. Drying
reduces the water content, concentrates the solids and nutrients, increases the calories per
ounce, and raises the amount of sodium.Medical Uses and/or Benefits
Protection against cardiovascular disease. The most important fats in fish are the poly-
unsaturated acids known as omega-3s. These fatty acids appear to work their way into
heart cells where they seem to help stabilize the heart muscle and prevent potentially
fatal arrhythmia (irregular heartbeat). Among 85,000 women in the long-running Nurses’
Health Study, those who ate fatty fish at least five times a week were nearly 50 percent
less likely to die from heart disease than those who ate fish less frequently. Similar results
appeared in men in the equally long-running Physicians’ Health Study. Some studies
suggest that people may get similar benefits from omega-3 capsules. Researchers at the
Consorzio Mario Negri Sud in Santa Maria Imbaro (Italy) say that men given a one-gram
fish oil capsule once a day have a risk of sudden death 42 percent lower than men given
placebos (“look-alike” pills with no fish oil). However, most nutrition scientists recom-
mend food over supplements.