Farmed tilapia contains low levels of beneficial omega-3 fatty acids and high levels of detrimental omega-6 fatty acids, a potentially hazardous combination for patients vulnerable to inflammation, which can damage the heart, blood vessels, lungs, skin and digestive tract, according to researchers at Wake Forest University School of Medicine in Winston-Salem, N.C.
In an article published in this month's edition of Journal of the American Dietetic Association, the research revealed that farmed tilapia and catfish "have several fatty acid characteristics that would generally be considered by the scientific community as detrimental.
"For individuals who are eating fish as a method to control inflammatory diseases such as heart disease, it is clear from these numbers that tilapia is not a good choice," the researchers said in a July 8 press release. "All other nutritional content aside, the inflammatory potential of hamburger and pork bacon is lower than the average serving of farmed tilapia."
The researchers found that farmed tilapia contain minimal amounts of omega-3s - less than half a gram per 100 grams of fish, similar to flounder and swordfish, while farmed salmon and trout contain nearly 3 and 4 grams, respectively. At the same time, tilapia contains much higher amounts of omega-6s, particularly arachidonic acid (AA), than salmon and trout. The ratio of AA to the omega-3 eicosapentaenoic acid (EPA) in tilapia average about 11:1, compared to 1:1 in salmon and trout.
"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," said the article's lead author, Floyd "Ski" Chilton, Ph.D., professor of physiology and pharmacology and director of the Wake Forest Center for Botanical Lipids.
Chilton is author of the 2005 book "Inflammation Nation," which claims inflammation is the underlying cause of heart disease, allergies and asthma. Chilton and contributor Laura Tucker claim that inflammation occurs when people consume too many "foods of affluence," such as farmed salmon, eggs and out-of-season fruits and vegetables.
"There is an on-going discussion about these fatty acids, but it's a dangerous reach to even suggest that replacing a meal of low-fat tilapia with ground beef or bacon would be a healthful choice," says Jennifer Wilmes, a registered dietitian and spokeswoman for the National Fisheries Institute in McLean, Va., adding that there is currently no scientific consensus that lower-omega-3, higher-omega-6 fish, such as tilapia, are unhealthy.
In an editorial that ran alongside the article, William Harris, Ph.D., director of the Metabolism and Nutrition Research Center at the University of South Dakota-Sioux Falls, challenged the research, pointing out that it "fails to consider relevant human experimental evidence" and attacks the dramatic comparison of tilapia to hamburger and bacon, calling it a "potentially flawed concept" that overstates the impact of omega-6s.
"We need more science to agree on the impact of an omega-3 to omega-6 ratio," says Wilmes. "But what we do have scientific consensus on is that omega-3s, which you can get plenty of by eating a variety of fish, are paramount to heart disease prevention."
The American Heart Association recommends that heart patients eat seafood twice a week due to the heart-protective attributes of omega-3s. The health benefits of eating a variety of seafood twice a week outweigh the risks, according to two major studies released by the Institute of Medicine and Harvard School of Public Health in October 2006.
To conduct the study, the researchers collected frozen tilapia samples from numerous sources, including producers and distributors in several countries and supermarkets in four states, and tested the samples using gas chromatography.
The research was funded by the National Center for Complementary and Alternative Medicine and the National Institutes of Health's Office of Dietary Supplements, and by an NIH Molecular Medicine training grant.
Tilapia ranked fifth on the U.S. seafood consumption list at almost 1 pound per capita in 2006, up from just 0.317 pounds in 2002. Tilapia is farmed predominately in Latin America and Asia.
Chilton conducted "several" phone interviews on Tuesday about the new research with national media outlets, says Wake Forest spokesman Mark Wright.
