Here's How Anti-Obesity 'Brown Fat' Helps Protect Health

The human body contains small amounts of a type of adipose tissue called 'brown fat' that, unlike its white fat counterpart, generates heat and burns calories. Past research has found evidence that higher levels of brown fat are linked to improved health, including lowered obesity and diabetes risk. In a new study, researchers reveal how brown fat helps protect health in this way and it involves essential amino acids.

Brown fat is known as a thermogenic tissue, meaning that it burns calories to generate heat. This type of fat is found in many mammals, including humans. Brown fat is at its highest level in humans during infancy, helping their tiny bodies withstand colder temperatures. As a human gets older, their brown fat stores dwindle, though tiny amounts remain near the kidneys, spinal cord, neck, and collarbone.

Brown fat has been investigated as a potential way to target obesity and some speculate that increasing brown fat levels may increase the number of calories burned, reducing weight gain and helping prevent obesity-related health conditions before they arise. Brown fat's anti-obesity effects may be due to more than just calorie burning, however.

Research out of Rutgers University investigated brown fat and found that it may help protect health by targeting isoleucine, leucine, and valine, three essential amino acids called branched-chain amino acids (BCAAs). The human body requires a total of nine essential amino acids, which refers to amino acids that cannot be created by the body itself.

BCAAs are required in normal concentrations to maintain health but may contribute to the development of obesity and diabetes if excessive concentrations are present in the blood. In addition to foods like meat and eggs, BCAAs are a common ingredient in many workout supplements and products sold for muscle growth.

The new study found that having no or very low levels of brown fat may reduce the body's ability to clear BCAA concentrations in the blood, potentially putting someone at risk for the development of obesity and diabetes linked to high concentrations. As well, the study found that a protein called SLC25A44 is the mechanism that controls how rapidly brown fat clears BCAAs from the blood, ultimately using them to generate heat.

The university notes that the researchers will need to look into whether brown fat's clearing of BCAAs is controllable by environmental factors and/or drugs — for example, whether exposure to chilly weather may influence the rate of uptake. Doing so may open the door for methods to boost brown fat function and help the body resist obesity and diabetes.

The idea of activating brown fat to burn calories isn't a new one, but it's unclear how effectively one could boost this heat-generating tissue. Exposure to cold temperatures has been implicated in past studies as a way to trigger brown fat into generating heat, which makes sense given the fat's purpose in helping keep babies and small animals warm.

Last year, a study out of the Technical University of Munich found that diet can also influence brown fat activation. Researchers found that brown fat may be activated to generate heat when a person eats a meal rich in carbohydrates. This activation was similar to the activation found in individuals who were exposed to cold temperatures.