Scientists have recently revealed a link between the presence of brown fat in the body and various health benefits, such as a lower risk of type 2 diabetes.

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This image shows a close-up of a layer of fat tissue.
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In a new study, scientists have revealed that the presence of brown fat in a person’s body is associated with a reduced risk of several cardiometabolic conditions.

The research, which now appears in the journal Nature Medicine, lays the groundwork for future research to explore which possible mechanism may underlie this association.

Most of the fat in a person’s body is white fat. White fat stores extra energy in large fat droplets that accumulate around the body. Having too much of this can lead to overweight or obesity.

Brown fat is different. Brown fat stores its energy in a smaller space, and, being rich in mitochondria, burns energy, which produces heat. Cold conditions can activate brown fat, though levels of brown fat can vary from person to person.

There has been much research into whether or not brown fat may have a role as a means to reduce obesity because of the way it expends energy. However, it is not yet clear if brown fat is a viable target for weight loss or as a weight management aid.

Although it may not be clear whether or not brown fat can help reduce obesity, there is emerging evidence associating the presence of brown fat in the body with certain health benefits.

That said, making this link clear is difficult. Large-scale studies are not feasible due to the challenges in detecting brown fat. This is because researchers can only detect brown fat using PET scans.

According to first study author Dr. Tobias Becher, of The Rockefeller University in New York City, NY: “These scans are expensive, but more importantly, they use radiation. We don’t want to subject many healthy people to that.”

To get around this issue, Dr. Becher accessed a collection of PET scan results from the Memorial Sloan Kettering Cancer Center, also in New York City, NY. Healthcare professionals had taken these scans as part of people’s cancer diagnosis or treatment.

When taking these scans, radiologists note the presence of brown fat to ensure that they do not confuse it with the presence of tumors. For Dr. Becher, “We realized this could be a valuable resource to get us started with looking at brown fat at a population scale.”

The researchers looked at 130,000 scans from over 52,000 people. They found that almost 10% of these individuals had brown fat deposits.

However, this could be an underestimation; before their scans, the people received instructions to avoid exercise, caffeine consumption, and cold weather. These factors can all increase the activity of brown fat.

The researchers found a clear association between the presence of brown fat in a person’s body and their risk of various cardiometabolic conditions.

For example, 4.6% of the people with detectable brown fat had type 2 diabetes, compared with 9.5% of the people without.

The researchers also found that 18.9% of people with brown fat had abnormal cholesterol, compared with 22.2% of those without brown fat.

There was also an association between the presence of brown fat in a person’s body and a lower risk of coronary artery disease, hypertension, and congestive heart failure.

Interestingly, the protective effects of brown fat seemed most pronounced in people who had obesity, reducing key cardiometabolic conditions to levels typical in people without obesity.

“It almost seems like they are protected from the harmful effects of white fat,” says senior study author Dr. Paul Cohen, the senior attending physician at The Rockefeller University Hospital.

The researchers are not yet sure which mechanism explains the link between brown fat and a reduced risk of cardiometabolic conditions.

Importantly, the study demonstrates an association, rather than a causal relationship, between the two.

Nonetheless, the researchers speculate that the brown fat cells may contribute to lowering a person’s blood glucose levels as they burn energy. Having high blood glucose levels is a significant risk factor for type 2 diabetes.

However, this would not explain the association the researchers found between brown fat and hypertension. Hypertension is a condition typically linked to a person’s hormonal system.

For Dr. Cohen, “We are considering the possibility that brown fat tissue does more than consume glucose and burn calories, and perhaps actually participates in hormonal signaling to other organs.”

The scientists plan to develop their research by looking at possible genetic explanations for why some people have more brown fat than others. This could open the door to the use of brown fat as a treatment for some cardiometabolic conditions.

According to Dr. Cohen:

“The natural question that everybody has is, ‘What can I do to get more brown fat?’ We don’t have a good answer to that yet, but it will be an exciting space for scientists to explore in the upcoming years.”