Here’s the Skinny on our Brown Fat

by Susan Davis on 10/04/09 at 11:03 am

First, we had to unravel and understand the differences between good and bad cholesterol. 

Now researchers at the Joslin Diabetes Center have discovered that adult humans still have a type of “good” brown fat previously believed to be present only in babies, children and animals. Unlike the “bad” white fat, which stores energy and makes up most body blubber, this good brown fat is active in burning calories, using energy and regulating body weight and blood sugar. The findings, reported in the April 9th issue of The New England Journal of Medicine, could pave the way for new treatments for both weight control and diabetes.  Essentially, our good brown fat could help us stay thin. 

The findings were discovered after researchers examined positron emission tomography and computed tomography (PET and CT) scans from nearly 2,000 people who were getting the procedures for a variety of non-research related conditions over a three-year period.

“The fact that there is active brown fat in adult humans means this is now a new and important target for the treatment of obesity and type 2 diabetes,” said C. Ronald Kahn, M.D., senior author of the study, head of the Joslin Section on Obesity and Hormone Action and professor of medicine at Harvard Medical School.  

Obesity is a major risk factor for type 2 diabetes.  According to the researchers, the idea behind a new therapy would be to find a way to stimulate brown fat growth to both control weight and improve glucose metabolism.  Higher levels of brown fat may also protect against age-related obesity.  All of this is good news for those of us who love to eat but hate to count calories!

Not surprisingly, the study found that younger patients were more likely to have larger amounts of brown fat, and the brown fat was more active during colder weather, keeping with its role of burning energy to generate heat. Brown fat was also more common in adults who were thin and had normal blood glucose levels.  However, the brown fat did not show up on the  body where it was most expected.  In adults, the brown fat was found around the neck, collarbone and around the spine.

Kahn said there is a good possibility that brown fat may be present in significant amounts in much higher percentages of the U.S. population, but that it may be more spread out throughout the body and not as easily detected on scans or imaging films.  Additional studies would be necessary to prove this theory.
 
“There has been a long debate as to whether brown fat exists in adult humans and whether it was important,” he said. “This study demonstrates that it is both present and appears to be physiologically important in terms of body weight and glucose metabolism.  We hope this opens up new therapeutic areas for obesity and type 2 diabetes.”

Essentially, researchers say that if we can figure out how to maintain more of the brown fat, then we may be able to unlock the key to permanent weight loss.  Of course, what any foodie really wants to know, is whether this means we’ll be able to eat as much and as often as we choose!

Related articles

• Busting the Cholesterol Myths (naturalbias.com)
• Why Do Some People Stay Thin? (losethattyre.co.uk)