A new US study suggests that about half of the US population has a common gene variant that makes them metabolize sugar and fat differently which could increase their risk of developing diabetes.

The research is published in the January edition of the American Journal of Clinical Nutrition.

"That is not to say that half of US residents are destined to get diabetes," says Edward Weiss, PhD, Assistant Professor of Nutrition and Dietetics at Doisy College of Health Sciences at Saint Louis University who led the study. The gene variant appears to contribute to diabetes risk, it does not cause diabetes on its own, he adds. Other factors are also involved.

Dr Weiss and colleagues studied the fatty acid binding protein 2 gene (FABP2). The gene is thought to regulate the uptake, transport, and intracellular metabolism of long-chain fatty acids obtained from the digestion of fat from food.

The gene has been studied before in connection with glucose regulation, and fat metabolism processes such as postprandial lipemia (excessive lipid levels after eating), and lipid oxidation. However, this was the first study to exclude the effects of regular exercise and diet.

Dr Weiss and colleagues took 122 sedentary, non-diabetic men and women who had been following a low fat diet. Some of them carried the Thr54 version of the FABP2 gene and the others did not.

They found that the people who had the Thr54 version of the gene processed fat differently to the others. They had a higher lipid oxidation rate, but lower glucose tolerance and lower insulin action, than the non-Thr54 group.

The researchers suggest that the group with the Thr54 variant burned more fat, and this may have got in the way of the metabolism of glucose, leaving more of it in the bloodstream. Too much sugar in the blood is the main characteristic of diabetes.

Dr Weiss said "This study adds to what was previously known about this gene variant by showing that after consuming a very rich milkshake, people with the variant gene process the fat from the drink differently than other people."

He added that the overall risk of a person developing diabetes is not straightforward, "Many other genes, some known and some unknown, are involved," he said, and there are some things that a person cannot control. But there are also things they can control, for instance "lifestyle factors, such as diet and exercise."

"FABP2 Ala54Thr genotype is associated with glucoregulatory function and lipid oxidation after a high-fat meal in sedentary nondiabetic men and women."
Edward P Weiss, Josef Brandauer, Onanong Kulaputana, Ioana A Ghiu, Christopher R Wohn, Dana A Phares, Alan R Shuldiner and James M Hagberg.
American Journal of Clinical Nutrition, Vol. 85, No. 1, 102-108, January 2007.