FRIDAY, July 11, 2008 (HealthDay News) -- The wildly popular farm-raised fish known as tilapia may actually harm your heart, thanks to low levels of healthy omega-3 fatty acids and high levels of unhealthy omega-6 fatty acids.
New research suggests the combination could be particularly bad for patients with heart disease, arthritis, asthma and other diseases involving overactive inflammatory responses.
"If you're in a vulnerable population such as a heart disease patient, you need to be very careful with what you're eating, and that includes everything," said senior study author Dr. Floyd H. Chilton, director of Wake Forest Center for Botanical Lipids, in Winston-Salem, N.C. "But when it comes to fish, there's not a more important thing you can do for heart disease than eat the right type of fish or take dietary fish oil. There is evidence that you may harm yourself by eating the wrong kind of fish, and [farmed] tilapia and catfish are the two that fall into that category."
"I don't think that this is an issue for everyone, any more than eating a hamburger is an issue for everyone," Chilton added.
The study was published in the July issue of the Journal of the American Dietetic Association.
As for suppliers, "the industry needs to improve ways of farming fish," said Katherine Tallmadge, a national spokeswoman for the American Dietetic Association. "The whole idea of farming is a great one, but they're feeding the fish food that's inexpensive, so they can keep the price down, and it's having an adverse effect on the nutritional quality of the fish."
Several health groups, including the American Heart Association, recommend eating two servings of fish a week, preferably fatty fish such as salmon. The reason: primarily to increase omega-3 fatty acids.
But no one has really looked at the nutritional effect of an explosion in farmed fish (increasing at an annual rate of 9.2 percent, compared with 1.4 percent for wild fish). In particular, inexpensive tilapia is exploding in popularity.
This study used gas chromatography to analyze the fatty acid composition of 30 widely consumed farmed and wild fish.
Farmed trout and Atlantic salmon had relatively good concentrations of "good" omega-3 fatty acids compared with "bad" omega-6 fatty acids.
Farm-raised tilapia and catfish, on the other hand, had troubling ratios.
Tallmadge recommends looking for wild fish. Wild salmon, even canned wild salmon, has high levels of omega-3s and is an excellent source of protein. "It can be fairly economical," she said. "I buy frozen salmon at Trader Joe's for about $7 a pound, that's $2 a serving."
Concentrate on cold-water fish such as salmon, rainbow trout, sardines, tuna and anchovies, all of which have healthy fats, added Marianne Grant, a health educator with Texas A&M Health Science Centers Coastal Bend Health Education Center, in Corpus Christi.
"In the 1970s, we lost the ability to feed the planet with fish we catch," Chilton said. "Farm-raised fish has to be part of our future, but we must do it correctly. We must feed animals the correct foods. Animals become what we feed them, and we become what we eat as well. The food chain is fairly consistent."
More information
Visit the American Heart Association for more on fish and fatty acids.
