For years the American Heart Association has suggested eating fatty fish at least twice a week because it is high in omega-3 fatty acids, which the body needs but does not produce.
“Research shows that omega-3 fatty acids reduce inflammation and may help lower risk of chronic diseases such as heart disease, cancer, and arthritis. Omega-3 fatty acids are highly concentrated in the brain and appear to be important for cognitive (brain memory and performance) and behavioral function,” according to the University of Maryland Medical Center.
But all of that is being challenged by a study published September 18 in the journal Science. The study looked at the genomes of the Inuit population in Greenland, whose diet consists mainly of proteins and fat from fish. Because Arctic peoples have a low rate of heart attack and stroke, many health experts thought the omega-3 fatty acids were protective.
The recent study looked at the genomes of 191 Inuit in Greenland, 60 Europeans, and 40 Chinese, and found that the Inuit have a genetic variant called FADS, or fatty acid desaturases, that help regulate the fats in our bodies, including omega-3 fatty acids.
Rasmus Nielson, a geneticist at the University of California, Berkeley and one of the authors of the latest study, said this gene variant discovery raised questions about whether omega-3 fats were protective for everyone. “The same diet may have different effects on different people,” he told the New York Times.
Almost every Inuit who participated in the study had the gene variant, which is far less common in other populations—only two percent of Europeans have it. Researchers who were part of the study believe that the Inuit evolved a way to bring the blood levels back into a healthy balance because they take in so much omega-3. “It seems that a genetic adaptation has counteracted the high intake of omega-3 fatty acids,” Marit E. Jorgensen, an author of the study from the University of South Denmark, told the New York Times.
The gene variant did more than change blood levels of fatty acids though, those who carried two copies of the gene, were about an inch shorter and 10 pounds lighter than those who did not have the gene.
The Times reports that Nielson and his colleagues plan to continue with their research, and investigate why some metabolize fats more effectively than others, and why omega-3s haven’t necessarily had the heart benefits researchers once hoped they would.
“Very soon, these results could be translated into help for people with their dietary choices,” Dr. Nielsen told the Times.