Brown fat may be good for you: study

Brown fat - a special type of fat that burns energy to produce heat - may also help to keep blood sugar steady in adults, researchers say.
Scientists from Sydney's Garvan Institute of Medical Research in Australia measured brown fat activity and blood glucose continuously in real time in study participants, and 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.
The incidence of type 2 diabetes, which is characterised by high blood sugar, is reaching epidemic proportions worldwide, researchers said.
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, brown fat acts like a heat generator, helping to keep us warm by burning sugar and fat, they said.

"Brown fat takes up so much glucose that we wondered whether brown fat could affect the concentration of glucose in the blood - and whether, therefore, brown fat-targeted therapies might help control diabetes," said Paul Lee from Garvan Institute of Medical Research.

"Previously, we showed that individuals with large brown fat stores tend to be lean and have lower blood glucose - and now, we have uncovered a potential link between brown fat activity and blood glucose variations," Lee said.
Researchers studied a group of 15 healthy adults over 12 hours. They found that blood glucose levels and heat production by brown fat were closely related, tracking together over time.

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 interestingly, their glucose fluctuations were greater. 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," said Lee.

The study used a simple and non-invasive technique to measure brown fat activity - a small thermometre placed over the collarbone of participants.
"Brown fat sits just under the skin, and it heats up when it is active. So, measuring skin temperature at the collarbone can allow us to estimate brown fat activity," said Lee.
"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," he said.
The findings were published in the journal Cell Metabolism.