Farmed tilapia may not be a good choice of fish for patients with coronary conditions
According to researchers from Wake Forest University School of Medicine*, farm-raised tilapia contains very low levels of beneficial omega-3 fatty acids and very high levels of omega-6 fatty acids.
In an article published in the July edition of Journal of the American Dietetic Association**, the Wake Forest researchers say that combination of low amounts of omega-3 and high amounts of omega-6 could make the fish 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.”
“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 says.
Scientists say their research revealed that farm-raised tilapia and catfish “have several fatty acid characteristics that would generally be considered by the scientific community as detrimental”. According to the article, the levels of long-chain omega-6 fatty acids are higher in farm raised tilapia than in 80-percent-lean hamburger, doughnuts and even pork bacon.
“All other nutritional content aside, the inflammatory potential of hamburger and pork bacon is lower than the average serving of farmed tilapia,” Wake Forest researchers explain.
The researchers used gas chromatography to analyse the contents of the fish and tested variety of fish from several different sources, including supermarkets in four U.S. states, seafood distributors that supply restaurants and supermarkets, two South American companies, and fish farms in several countries. Pending analysis, all samples were snap-frozen to preserve nutrients.
The gas chromatography analysis showed that farmed tilapia contained less than 0.5 grams of omega-3 fatty acids per 100 grams of fish. Farmed salmon and trout did however contain considerably higher amounts; almost 3 grams and 4 grams, respectively.
The analysis also showed that farmed tilapia contained higher amounts of omega-6 acids than both salmon and trout. In farmed tilapia the ratio between long-chain omega-6 to long-chain omega-3 average about 11:1, which can be compared to the average ratio of less than 1:1 found in salmon and trout.
The importance of the omega-6 / omega-3 ratios vs. the concentration of long-chain omega-3 alone is currently being heavily debated by scientists.
Dr Floyd H. “Ski” Chilton***, the senior author of the Journal article, said tilapia is easily farmed using inexpensive corn-based feeds, which contain short chain omega-6s that the fish very efficiently convert to AA [omega-6] and place in their tissues.
“We are all familiar with the classical Hippocratic admonition, Primum no nocere, ‘First, do no harm.’ I think it behooves us to consider this critical directive when making dietary prescriptions for the sake of health,” Chilton said. “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.”
* Wake Forest University School of Medicine, along with North Carolina Baptist Hospital and Wake Forest University Physicians, is part of the Wake Forest University Baptist Medical Center system. It is located in Winston-Salem, North Carolina in the United States.
** http://www.adajournal.org/
***Floyd H. “Ski” Chilton, Ph.D., professor of physiology and pharmacology and director of the Wake Forest Center for Botanical Lipids
