A new study has found a link between brown fat and exercise-related metabolism boost. The study, led by Kristin Stanford of The Ohio State University Wexner Medical Center, found that a lipid released from fat, produced by brown fat, surges in the bloodstream after exercise.
Brown fat, known as a powerful calorie burner, has the unique ability to generate heat. In cold conditions, brown fat uses a combination of its own energy stores and other substances to generate heat. Surprisingly, brown fat is also active under warm conditions.
Until 2009, it was believed that only human babies had brown fat. Recent studies have found that brown fat accounts for a small amount of adult fat stores.
The research focused on two study groups, which underwent blood testing to evaluate lipid changes after moderate-intensity exercise. One group ran on the treadmill for 45 minutes, while the other group rode a stationary bike for 40 minutes.
Levels of one specific lipid – called 12, 13 diHOME – rose sharply after exercise. Previously, the fat molecule had only been linked to cold temperature exposure.
Levels of 13 other lipids had decreased significantly after exercise.
“This study shows that burning of brown fat and this lipid in particular likely play an important role,” said Stanford.
Stanford says that during exercise, brown fat signals the muscle to “take up more fatty acids to use as fuel.”
White adipose tissue breaks down fat stores to create circulating fatty acids. Brown fat releases a lipid that triggers the uptake of these fatty acids into working muscles. One source of fat provides the fuel, while the other signals the muscles to use that fuel.
The results of the study may improve the way exercise, nutrition and supplements, like fat loss powder, work together to help people reach their fitness goals.
To confirm the link between exercise and brown fat, researchers conducted a study on mice. They found that levels of lipid also rose after the animals exercised. After surgical removal of brown fat stores in mice, levels of the lipid did not rise. The findings suggest that brown fat is the source of the lipid.
“This shows that these lipokines can be regulated by exercise, and it highlights a new role that brown fat could play in the metabolic benefits of exercise,” says Standford.
Future studies will explore the physiological effects of signaling lipids that are decrease during exercise and look at how 12,13-diHOME works.