News and Public Affairs

The Food and Drug Administration and the Environmental Protection Agency are drafting a warning that advises pregnant women and children to limit their intake of tuna and other fish and shellfish to 12 ounces a week, roughly two or three servings. They also advise all Americans to mix the types of fish they eat and to avoid consuming too much other saltwater fish, such as shark, swordfish and mackerel. All of these species may contain high levels of mercury, a toxic substance linked with cardiovascular disease and neurological damage.

The new warning brings added frustration to the millions of Americans who have made an effort in recent years to eat more fish. Studies have shown that omega-3 fatty acids, which abound in ocean-caught sporting fish, may be a powerful safeguard against heart disease and neurological damage that frequently accompany aging.

Still, the question remains: If ocean-caught fish should be eaten only in moderate amounts, where do we look for these omega-3’s? Farm-raised fish, such as salmon and catfish, free of the contamination associated with ocean-caught fish, seem like obvious alternatives. But there’s one hitch: While perfectly safe excellent low-fat sources of protein, neither of these fish necessarily compare favorably with ocean-caught fish --- at least from the standpoint of omega-3 fatty acids.

“With catfish, for example, most omega-3 fatty acids are deposited in the abdomen or below the skin. They don’t lay down a lot of it in their muscle tissue,” said Dr. Russell Wright, an Alabama Cooperative Extension System fisheries specialist and Auburn University associate professor of fisheries and allied aquacultures. “So when we clean the fish, we tend to do away with a lot of the omega- fatty acids, though there will still be some in the tissue.”

Also, the types of Omega- fatty acids commonly found in catfish don’t compare favorably with those in saltwater fish. Tuna especially abounds in the long-chained omega-3, such as DHA, commonly considered the best safeguard against cardiovascular disease and neurological damage. Catfish, on the other hand, pales in comparison, said Dr. Allen Davis, an Auburn University assistant professor of fisheries, who specializes in aquatic nutrition. The highly unsaturated omega-3 fatty acids associated with heart and brain health can be added through feeding, but only to a limited degree, he said.

Farm-raised salmon can be an exceptionally good source of omega-3 fatty acids but only as long as they receive adequate amounts of omega-3’s on the farm.

“It all depends on what they were fed on the farm,” said Dr. Robert Keith, and Extension nutritionist and Auburn University professor of nutrition and food science. “If they eat plants or commercial feeds that are high in omega-3’s, you can count on their being good sources of omega-3 fatty acids. But it all boils down to what they’re eating.”

Farm-raised salmon is now the most common source of salmon in the United States.

“The vast majority of fresh filet salmon commonly sold in seafood and supermarkets is farm raised,” Wright said. “In fact, you really have to go out of the way to find ocean-caught salmon.”

Canned salmon, on the other hand, is almost entirely derived from wild-caught salmon, he said.

Keith said supplements are an alternative for consumers unwilling or unable to eat fish, but they lack the other benefits associated with fish.

The incentive for salmon farmers to supplement feeds with omega-3 just got stronger. Convinced that omega-3 fatty acids are a powerful safeguard against heart disease, the American Heart Association recommended in November that Americans with heart disease consume at least one gram of omega-3 fatty acids daily to reduce their risk of heart attacks. This marks the first time the AHA has recommended a food supplement as a method for sustaining heart health.

[Sources: Dr. Russell Wright, Extension Fisheries Specialist and Auburn University Associate Professor of Aquaculture and Allied Aquacultures, (334) 844-9311; Dr. Robert Keith, Alabama Cooperative Extension System Nutritionist and Auburn University Professor of Nutrition and Food Science, (334) 844-3273; Writer: Jim Langcuster, Extension Communications Specialist, News and Public Affairs, (334) 844-5686.]

Article in MS Word

Article in Text