Nutrition-wise blog

Catfish and tilapia: Healthy or harmful?

By Jennifer K. Nelson, R.D., L.D. and Katherine Zeratsky, R.D., L.D. July 17, 2008

There's an interesting discussion in this month's "Journal of the American Dietetic Association." What it boils down to is this: Is the fatty acid mix in catfish and tilapia healthy or harmful? The debate has even reached the popular press. Why all the fuss?

First off, since 2000, catfish and tilapia rank as two of the most popular fish consumed in the United States thanks mainly to their taste and relatively low expense. And both contain heart-healthy omega-3 fatty acids.

Consumption of these types of fatty acids is thought to be associated with reduction in blood pressure and reduced risk for certain cancers, inflammatory conditions such as rheumatoid arthritis, and even mental decline.

You may not have heard so much about a second ingredient they contain, omega-6 fatty acids. Like omega-3s, these are polyunsaturated and help lower blood cholesterol levels, however they are thought to play a role in clotting function, are inflammatory and susceptible to oxidation — thereby possibly increasing risk for blood clots, arthritis, inflammatory bowel disease and cancers.

The National Institutes of Health funded study by Weaver and colleagues looked at the favorable omega-3 fatty acid content and unfavorable omega-6 contents of commonly eaten fish and found that while catfish and tilapia contain both, they contain a high amount of unfavorable omega-6 fat.

They report that a 3-ounce portion of catfish or tilapia contains 67 and 134 milligrams respectively of the bad fat (the same amount of 80 percent lean hamburger contains 34 milligrams, and bacon 191 milligrams).

Does this mean you should give them up? No! The rebuttal by Harris is in the same journal. He says the logic of judging fatty fish by the amounts of omega-3 and omega-6 fat contents is flawed. Governmental and professional organizations haven't used such a ratio for years.

He also says that to think that eating catfish or tilapia — because of its high omega-6 content — is more risky in terms of heart disease than eating bacon or hamburger is "flawed."

My take? I'm going to continue to eat fish — at least twice weekly. I'm going to choose a variety of fatty fish — including tilapia and catfish along with others especially high in the good fats such as salmon, tuna and mackerel.

P.S. When you see this on the evening news you can say that you got the scoop here.

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Jul. 17, 2008