Issue 128 Item 6 Visceral Fat Removal Stops Insulin Resistance

Visceral fat removal can halt a decrease in insulin action and delay the onset of diabetes. researchers report in the October issue of Diabetes. They propose that "specific interventions to reduce intra-abdominal fat could vastly improve insulin action as we age."

Dr. Nir Barzilai of Albert Einstein College of Medicine, the Bronx, New York, and colleagues note that age-dependent changes in insulin action and body fat distribution are risk factors for the development of type 2 diabetes.

Furthermore, they say, "among various body fat depots, the amount of visceral fat (VF) best correlates with insulin sensitivity in animal models and in humans." To investigate further, the researchers studied the effect of VF removal in aging (20 month-old) Brown Norway rats and in Zucker Diabetic Fatty rats.

Peripheral and hepatic insulin action, which had been markedly impaired in the Norway rats, was restored to the level seen in young rats. In the Zucker rats, VF removal prevented a progressive decrease in insulin action and delayed the onset of diabetes. There was also a marked decrease in tumor necrosis factor-alpha and in leptin in subcutaneous adipose tissue.

Dr. Barzilai stated that "while we didn’t know if the metabolic changes of aging cause change in fat distribution, or that changes in fat distribution cause the metabolic changes of aging–this study suggests the latter."

Although surgical removal would hardly be an answer in humans, because of potential intestinal injury, he added that he and his colleagues are investigating "the mechanisms by which fat is distributed–through the action of the hormone leptin–and hope to develop a drug therapy." Diabetes 2002;51:2951-2958.