There’s Nothing Fishy About the Benefits of the Real Thing
We often don’t acquire a taste for fish until adulthood--unless you count fish sticks, which sometimes end up as a favorite toddler food. But fish is an important part of a healthy diet, and a taste well worth acquiring.
The research on fish eaters is mixed. Some studies show that the rate of heart disease is lower in countries where fish is a major part of the diet. But research from Finland, where fish consumption is high, shows that the rate of heart disease is also high. When all is said and done, the consensus continues to be that adding a moderate amount of fish to the diet is a good idea.
The fat contained in fish is rich in a special form of polyunsaturated fatty acid called omega-3. The fattier the fish, the more omega-3 it contains. Omega-3 seems to work like aspirin and make the blood less “sticky” and thus less likely to form clots that could lead to fatal heart attacks.
Somehow, omega-3 also seems to lower the heart’s susceptibility to arrhythmias, which can be extremely dangerous and even fatal. On top of that, new research shows that fish oil may help with some autoimmune diseases, such as rheumatoid arthritis and even psoriasis.
Of course, not everybody likes fish, and it would be nice if fish oil capsules did the trick just as well. However, like most supplements that try to extract what are believed to be the “active” ingredients in foods, fish oil supplements are not the same as the oil eaten in the fish itself.
For one thing, we don’t know with certainty that it is just the oil in fish that seems to be most protective. It might be something else in the fish, or it might be the oil in combination with other substances in the fish.
Fish oil capsules contain very large doses of fish oil, which may be too much of a good thing when it comes to blood clotting. For example, if your blood is unable to clot properly, you might be at a higher risk for hemorrhagic stroke. You might also have a problem if you need to undergo emergency surgery, especially if the surgeon and anesthesiologist don’t know what you’re taking. The large quantities of fish oil in the capsules have other side effects, such as nausea, diarrhea, gas and can leave a bad taste in your mouth.
In any case, they should not be taken without consulting your physician. Apparently, people in this country have figured that out, because the sale of these supplements has dropped considerably while consumption of fish has risen.
One warning about eating fish: In January 2001, the U.S. Food and Drug Administration warned women who were pregnant or who might become pregnant to avoid some varieties of fish that might be contaminated with mercury. The warning was issued because of the possible effects that mercury may have on the brain and nervous system of a developing fetus.
Those fish most likely to contain mercury are shark, swordfish, king mackerel or tilefish. As a general rule, pregnant women are advised to eat no more than 12 ounces of fish a week and to vary the types of fish consumed so as to lessen the possibility of exposure to contamination.
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Sources of Omega-3
So which seafoods are the richest in omega-3? This chart from the April 2001 issue of the UC Berkeley Wellness Letter may be helpful. Although there is no actual U.S. recommendation for omega-3 intake, the Canadian Food and Drug Administration recommends 1 to 1.5 grams per day. This table shows the number of grams of omega-3 in one serving of fish.
Type of fish -- Grams
Atlantic mackerel -- 2.6
Lake trout -- 2.0
Atlantic salmon, farmed -- 1.9
Herring -- 1.8
Bluefin tuna -- 1.6
Chinook salmon -- 1.5
Sturgeon -- 1.5
Albacore tuna -- 1.5
Whitefish, lake -- 1.5
Sardines, canned -- 1.4
Bluefish, Atlantic -- 1.2
Salmon, pink -- 1.0
Halibut, striped bass, mullet, pollock, catfish, rainbow trout, carp, shrimp, crab, lobster -- 0.4 to 0.9
Sole, flounder, perch, cod, grouper, haddock, swordfish, red snapper, plaice, clams -- fewer than 0.3
Note: Serving size is 3.5 ounces
Source: UC Berkeley Wellness Letter
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Dr. Sheldon Margen is a professor of public health at UC Berkeley; Dale A. Ogar is managing editor of the UC Berkeley Wellness Letter. Send questions to Dale Ogar, School of Public Health, UC Berkeley, Berkeley, CA 94720-7360, or e-mail to daogar@wellnessletter.com. Eating Smart appears occasionally in Health.
