Researchers uncover potential genetic link behind higher rates of type 2 diabetes among African Americans

African Americans are known to have higher rates of type 2 diabetes than Caucasians, but the reasons behind this association are not well understood. Now, a new study suggests that the answer may lie in their genes.

A team of researchers from Wake Forest University and Johns Hopkins University reported in the journal BioMed Central Genetics that African Americans more efficiently convert omega-6 polyunsaturated acids (PUFA) into long-chain PUFAs.

This is important because long-chain PUFAs are often subsequently converted into inflammatory messengers. Higher levels of these substances have been observed to be associated with more inflammation, which often leads to insulin resistance and type 2 diabetes.

Prior research by the same group found that an alteration in a region of chromosome 11 known as the FADS cluster plays an important role in the ability of an individual to metabolize omega-6 PUFAS. They suspect that genetic testing of African Americans will reveal that a high percentage of these individuals have this variation and that this is the reason why they are more efficient at converting the fat into inflammatory messengers.

Still, the findings do not mean that all African Americans are doomed to develop type 2 diabetes. If a person excludes omega-6 PUFAs from their diet, the inflammatory process will never get started, something lead researcher Floyd Chilton, PhD, said is important to keep in mind.

He pointed out that these fats now make up about 8 percent of the average person’s daily caloric intake. However, several decades ago, they only accounted for about 2 percent. As red meat and processed foods have become more available, intake of these unhealthy fats has increased at alarming rates.

However, regardless of genetic risk factors, if African Americans avoid overindulging on these foods, they may be less likely to develop type 2 diabetes.

"This is an important example of why it is critical to advance the field of personalized nutrition," Chilton said. "Understanding which nutrients may be healthy for one population, but not for another will be essential to optimizing public health. I believe observations such as this begin to address the critical question of why Western diets seem to differentially impact African Americans with cardiovascular disease and diabetes at a higher rate than their Caucasian counterparts."

Answering this question could have important public health implications. African Americans develop type 2 diabetes at about 1.5 times the rate of Caucasians, according to the American Diabetes Association. The disease is more common among this racial group than any other in the U.S.

Some have suggested that socioeconomic factors may be among the strongest forces behind the skewing of these numbers. While these types of considerations doubtless play a role, the findings from the present study suggest that genetics are at least as responsible - if not more so - for the higher rates of type 2 diabetes among African Americans.