December 18, 2014

Gene regulators of circulating trans fatty acids identified

High consumption of trans fatty acids (TFA) has been linked to increased risk of heart disease, stroke and even cancer.

High consumption of trans fatty acids (TFA) has been linked to increased risk of heart disease, stroke and even cancer.

Despite efforts to reduce consumption of TFA, a substantial number of people still consume large amounts, mainly through frozen foods such as pizza or baked products that contain partially hydrogenated cooking oils.

Trans fats don’t appear naturally in the human body, which means the levels we have in our tissues depend on either the amount we consume or the way our bodies process them.

Unlike other fatty acids in the diet, little is known about what happens to TFA after they are consumed. The metabolic processing of TFA could influence circulating TFA concentrations and possibly modulate or mediate their impact on health.

Edmond Kabagambe, Ph.D., DVM, M.S.

A Vanderbilt researcher and his colleagues from other institutions conducted a study to understand genetic factors that determine tissue concentrations of TFA, and the results were published online in The American Journal of Clinical Nutrition.

“The objective of the study was to elucidate novel biologic pathways that may influence the amount of circulating TFA by evaluating associations between common genetic variants and TFA isomers measured in blood,” said author Edmond K. Kabagambe, DVM, Ph.D., M.S., associate professor of Medicine in the Division of Epidemiology.

Kabagambe and colleagues pooled data from seven prospective genome-wide association studies (GWAS) of phospholipid TFA levels across more than 8,000 participants of European descent.

They identified several single nucleotide polymorphisms in the GWAS and further evaluated them for association with circulating TFA levels among African-Americans, Chinese-Americans and Hispanic-Americans from two of the participating cohorts.

“We identified novel genetic variants that, in part, determine trans fatty acid concentrations in plasma and red blood cell membranes.

“This novel evidence of genetic regulation of trans fatty acid suggests shared pathways with other polyunsaturated fatty acids,” Kabagambe said.

Also of major interest is the finding that a common fatty acid, arachidonic acid, may influence genetic regulation of tissue concentrations of trans fatty acids.

Additionally, in the African-American population, the specific genetic variants associated with TFA levels were different from those found in participants of European, Hispanic or Asian descent, but in all studied populations all the variants were in the same gene cluster of fatty acid desaturase enzymes.

“I think we need to do more studies to understand exactly which other genes or individual genetic variants control how TFA are processed and how such differences may affect competition between TFA and other dietary fatty acids like omega-3 fatty acids,” Kabagambe said.

It will be important to determine whether some people have a higher genetic predisposition to retain more of the TFA they consume and whether that translates into increased risk for disease or not. These are the questions the investigators want to address next.