Noting data concerning the role of BAT in glucose metabolism in rodents, the researchers sought to determine whether BAT activation alters whole-body glucose homeostasis and insulin sensitivity in humans. Seven BAT-positive (BAT+) men and five BAT-negative men were exposed to either normal or slightly cold temperatures for five to eight hours. Age, body mass index, and adiposity were similar in the two groups. The researchers analyzed samples of the men’s blood and breath to monitor changes in their hormone, blood glucose, and insulin levels. The investigators also tracked their whole body oxygen consumption and carbon dioxide production rates.
The researchers found cold exposure significantly increased resting energy expenditure, whole-body glucose disposal, plasma glucose oxidation, and insulin sensitivity in the BAT+ group only.
“We showed that exposure to mild cold raised whole body energy expenditure, increased glucose removal from the circulation and improved insulin sensitivity in men who have significant amounts of brown adipose tissue depots,” Labros Sidossis, Ph.D., of the University of Texas Medical Branch at Galveston, said in a university news release. “These results support the notion that brown adipose tissue may function as an anti-obesity and anti-diabetic tissue in humans.”