The next time you visit the fish counter at your local natural and organic food store, you may wish to substitute salmon or trout for the lower-priced tilapia. 

Farm-raised tilapia, one of the most highly consumed fish in the United States, has very low levels of beneficial omega-3 fatty acids. It also contains very high levels of potentially detrimental omega-6 fatty acids. 

New research from Wake Forest University School of Medicine in North Carolina shows this combination could be potentially dangerous for some people with heart disease, arthritis, asthma, and other allergic and autoimmune diseases. These individuals are particularly vulnerable to an “exaggerated inflammatory response,” which can damage blood vessels, the heart, lung and joint tissues, the skin and the digestive tract. 

“In the United States, tilapia has shown the biggest gains in popularity among seafood, and 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 write in an article published this month in the Journal of the American Dietetic Association

Their research revealed that farm-raised tilapia, as well as farmed catfish, “has several fatty acid characteristics that would generally be considered by the scientific community as detrimental.” In fact, tilapia’s omega-6 fatty acid levels exceed those of 80% lean hamburger, doughnuts and even bacon. 

“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 article states. “All other nutritional content aside, the inflammatory potential of hamburger and pork bacon is lower than the average serving of farmed tilapia.” 

The health benefits of omega-3 fatty acids have been well documented, and the American Heart Association recommends eating at least two servings of fish per week. Heart patients are advised to consume at least 1 gram a day of the two most critical omega-3 fatty acids: EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). 

But the farmed tilapia researchers tested contained only modest amounts of omega-3 fatty acids: less than half a gram per 100 grams of fish, similar to flounder and swordfish. Farmed salmon and trout, by contrast, had nearly 3 and 4 grams, respectively. 

The tilapia tested had much higher amounts of omega-6 acids than salmon and trout, which prompts lead researcher Floyd H. Chilton, PhD, to assert that consumption is likely not worth the risk in vulnerable populations. 

He also noted that tilapia is easily farmed using inexpensive corn-based feeds, which contain omega-6s, and can be grown under almost any condition. This keeps its market price so low that it’s rapidly becoming a staple in low-income diets. 

“Cardiologists are telling their patients to go home and eat fish, and if the patients are poor, they’re eating tilapia,” says Dr. Chilton, a professor of physiology and pharmacology. “And that could translate into a dangerous situation.”