Eating tilapia, an increasingly popular fish in the South, may be risky for people with inflammatory conditions such as heart disease, according to researchers at Wake Forest University School of Medicine.
The researchers reported yesterday that farm-raised tilapia -- the fifth most popular fish consumed in the United States --has very low levels of beneficial omega-3 fatty acids.
"Perhaps worse, it contains very high levels of omega-6 fatty acids," the researchers said.
The combination "could be a potentially dangerous food source for some patients with heart disease, arthritis, asthma and other allergic and auto-immune diseases that are particularly vulnerable to an ‘exaggerated inflammatory response.'"
Inflammation is known to cause damage to blood vessels, the heart, lung and joint tissues, skin and the digestive tract.
"We are all familiar with the classical Hippocratic admonition, ‘First, do no harm,'" said Dr. Floyd "Ski" Chilton, a professor of physiology and pharmacology and the director of the Wake Forest Center for Botanical Lipids. "I think it behooves us to consider this critical directive when making dietary prescriptions for the sake of health."
"Cardiologists are telling their patients to go home and eat fish, and if the patients are poor, they're eating tilapia. And that could translate into a dangerous situation," he said.
The report is being published this month in the Journal of the American Dietetic Association.
It comes at a time when tilapia, which has a mild, less-oily taste, has shown the biggest gains in popularity among seafood.
"This trend is expected to continue as consumption is projected to increase from 1.5 million tons in 2003 to 2.5 million tons by 2010," the researchers wrote.
Tilapia is raised on farms in China and South America, as well as in Eastern North Carolina and Florida. It also has been linked to health concerns regarding high PCB and mercury levels, although the researchers said that "those concerns have been overblown in the media."
Tilapia is easily farmed by using inexpensive corn-based feeds, which together with their capacity to grow under almost any condition, keeps the market price low enough that it is rapidly becoming a staple in low-income diets.
However, officials with local restaurants said that the cost of tilapia has surged recently because of higher fuel costs associated with farming and distributing the fish.
"Essentially, what you feed tilapia is what you get out of them for food," Chilton said.
He said that it could take years and more studies before the Food and Drug Administration issues a formal warning.
Chilton said that consumers should still eat at least two servings of fish a week, but focus more on salmon, mackerel, albacore tuna and shrimp for better omega-3 benefits. He also recommended taking fish-oil supplements.
"All fish are not created equal when it comes to their nutritional benefit," said John Balbus, the chief health scientist for the Environmental Defense Fund.
Sean McKeon, the president of N.C. Fisheries Association Inc., said that the agency has no official position regarding farm-raised fish.
"However, we do see some fundamental problems with the system embracing and promoting farm-raised fish, especially imported species that are, in many cases, unencumbered by any FDA-type food regulations," McKeon said.
"The other major problem for our industry is that many consumers will not be able to differentiate between the researchers' warnings about farm-raised fish and wild-caught seafood harvested by our fishermen. Locally caught seafood harvested in U.S. waters is perfectly safe, and people should be eating more, not less of it," he said.
Jimmy Kontas, the owner of the Yacht House Seafood Restaurant in Winston-Salem, said he doesn't believe that the report will affect its sales of tilapia, which have been increasing in recent months.
"I'm sure once the story comes out that we'll get more questions about whether our tilapia is farm-raised, which it is," Kontas said. "What may affect our sales of tilapia more is the increasing cost of providing tilapia. We raised our prices in February, yet our costs continue to rise."
The research was financed by the National Center for Complementary and Alternative Medicine and the Office of Dietary Supplements of the National Institutes of Health, and by an NIH Molecular Medicine training grant.