In a new study led by Rutgers University, scientists have discovered how brown fat may help protect against obesity and type 2 diabetes.
The research is shedding new light on the role of brown fat in human health and may ultimately lead to the development of improved treatments for controlling weight and blood sugar.
Also known as brown adipose tissue, brown fat is considered a heat organ. It is found in small amounts in specific regions of the body, including the neck, collarbone, kidneys, and spinal cord. When brown fat is activated by cool temperatures, it uses sugar and fat from the blood to generate heat in the body.
The researchers determined that brown fat can also help the body filter and remove branched-chain amino acids (BCAAs) from the blood. BCAAs are found in foods like meat, fish, eggs, and milk, and are also found in supplements used by athletes to build muscle mass.
At normal levels, these amino acids are essential for good health. However, an excess of BCAAs in the blood is associated with diabetes and obesity.
According to the study, people with little or no brown fat have a more difficult time clearing BCAAs from their blood, which may lead to the development of weight and blood sugar problems.
The study has also unraveled a longstanding mystery about how BCAAs enter the mitochondria that generate energy and heat in cells. The scientists discovered a protein, SLC25A44, which controls the rate that brown fat eliminates the amino acids and uses them for energy and heat.
Study co-author Professor Labros S. Sidossis chairs the Department of Kinesiology and Health in the School of Arts and Sciences at Rutgers University-New Brunswick.
“Our study explains the paradox that BCAA supplements can potentially benefit those with active brown fat, such as healthy people, but can be detrimental to others, including the elderly, obese and people with diabetes,” said Professor Sidossis.
Next, the researchers will investigate whether uptake of BCAAs by brown fat can be controlled by environmental factors, such as exposure to mildly cold temperatures, the consumption of spicy foods, or by drug treatments. Sidossis said this could improve blood sugar levels that are linked to diabetes and obesity.
The study is published in the journal Nature.
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