Australasian Science: Australia's authority on science since 1938

Brown Fat Keeps Blood Sugar in Check

Brown fat, which burns energy to produce heat, may also help to keep blood sugar steady in adults.

Researchers at the Garvan Institute of Medical Research have found that individuals with more brown fat had smaller fluctuations in blood sugar. The findings open new avenues for diabetes therapies that target brown fat.

Unlike white fat, which primarily stores energy, brown fat burns energy – often in remarkably large amounts. Sitting just above the collarbone and in the neck, it acts like a heat generator, helping to keep us warm by burning sugar and fat.

Dr Paul Lee and A/Prof Jerry Greenfield found that blood glucose levels and heat production by brown fat were closely related, tracking together over time. Importantly, participants who had larger deposits of brown fat had less fluctuation in blood glucose – and blood glucose fell after each peak of brown fat activity surge.

In contrast, brown fat activity rose only in response to an increase in blood glucose among those with less brown fat, and their glucose fluctuations were greater. Notably, individuals with no detectable brown fat had the widest fluctuations in blood glucose.

“Our findings indicate that brown fat might act as a glucose buffer, lessening the variation in blood glucose and potentially diminishing metabolic stresses that could increase the risk of diabetes,” Lee said.

The researchers also observed that brown fat activity rose at dawn. “We speculate that this early morning temperature boost may have an evolutionary origin, generating heat and preparing our ancestors for hunting and gathering in the cold as the day begins,” Lee said.

“The study brings brown fat into the frame for developing diabetes therapies,” Lee said. “If we can pinpoint what switches brown fat’s activity on and off during the day, we may identify new targets in drug design.” However, he added that “it is not the solution to finding a cure for diabetes, at least not now. A balanced diet and regular exercise are the cornerstones of healthy metabolism and should not be forgotten.”

The research has been published in Cell Metabolism (www.tinyurl.com/z6gnuxg).