Omega-3 Content of Various Food Fish
Fish* (3 oz.) Omega-3 (grams)
Salmon, Atlantic 1.8
Anchovy, canned* 1.7
Mackerel, Pacific 1.6
Salmon, pink, canned* 1.4
Sardine, Pacific, canned* 1.4
Trout, rainbow 1.0
Tuna, white, canned* 0.7
Mussels 0.7* cooked, without sauce
* drainedSource: National Fisheries Institute; USDA Nutrient Data Laboratory. National Nutri-
ent Database for Standard Reference. Available online. UR L: http://www.nal.usda.
gov/fnic/foodcomp/search/.Adverse Effects Associated with This Food
Allergic reaction. According to the Merck Manual, fish is one of the 12 foods most likely to
trigger classic food allergy symptoms: hives, swelling of the lips and eyes, and upset stom-
ach. The others are berries (blackberries, blueberries, raspberries, strawberries), chocolate,
corn, eggs, legumes (green peas, lima beans, peanuts, soybeans), milk, nuts, peaches, pork,
shellfish, and wheat (see wheat cereals). NOTE: Canned tuna products may contain sulfites
in vegetable proteins used to enhance the tuna’s flavor. People sensitive to sulfites may suf-
fer serious allergic reactions, including potentially fatal anaphylactic shock, if they eat tuna
containing sulfites. In 1997, tuna manufacturers agreed to put warning labels on products
with sulfites.
Environmental contaminants. Some fish are contaminated with methylmercury, a compound
produced by bacteria that chemically alters naturally occurring mercury (a metal found in
rock and soil) or mercury released into water through industrial pollution. The methylmer-
cury is absorbed by small fish, which are eaten by larger fish, which are then eaten by human
beings. The larger the fish and the longer it lives the more methylmercury it absorbs. The
measurement used to describe the amount of methylmercury in fish is ppm (parts per mil-
lion). Newly-popular tilapia, a small fish, has an average 0.01 ppm, while shark, a big fish,
may have up to 4.54 ppm, 450 times as much.
That is a relatively small amount of methylmercury; it will soon make its way
harmlessly out of the body. But even small amounts may be hazardous during pregnancy
because methylmercury targets the developing fetal nervous system. Repeated studies
Fish