Brown Fat May Protect Against Numerous Chronic Conditions

Although “body fat” is often used as a general term, there are actually three different types of fat, and two of them—called brown and beige fat—can be beneficial for cardiometabolic health, according to a new study published in Nature Medicine.

Researchers looked at imaging scans from over 52,000 patients to determine their amount of brown fat, also called brown adipose tissue (BAT), then compared those results to previous diagnoses of cancer and cardiometabolic diseases such as:

• Type 2 diabetes
• High cholesterol
• Coronary artery disease
• Congestive heart failure
• Cerebrovascular disease
• High blood pressure

They found that those with higher BAT levels had lower prevalence of conditions like these, even if they were overweight or had obesity, suggesting that brown fat might play a role in mitigating the negative effects of excess weight in general.

Differences Types of Fat

The reason that brown and beige fat might be beneficial is that those types differ in terms of how they act in the body, according to the study’s lead author Paul Cohen, MD, PhD, in the Laboratory of Molecular Metabolism at The Rockefeller University in New York.

"White fat stores excess energy, and when that storage is in the abdomen—a common spot the body uses to stash its fat for later usage—it can significantly increase risk for numerous illnesses as well as earlier mortality," says Cohen.

By contrast, brown and beige fats are “thermogenic,” which means they burn energy instead of storing it, particularly as a way to heat the body in cold conditions. Thermogenic fat tissue has shown a considerable role in glucose regulation and lipid levels in mouse studies, and this research is the first time similar benefits have been shown for humans, Cohen states.

For example, only 4.6% of those with higher BAT had Type 2 diabetes, compared to 9.5% of those who did not. About 19% had high cholesterol, compared to 22% in those without brown fat. The study also revealed that people with higher BAT had lower risk of hypertension, congestive heart failure, and coronary artery disease—associations that had not been found in previous studies.

“These findings make us more confident about the potential of targeting brown fat for therapeutic benefit,” he says, adding that an especially compelling result was lower prevalence of cardiometabolic issues for those who are overweight but have higher BAT. “It almost seems like they are protected from the harmful effects of white fat.”

Future Research Direction

In terms of strategies for increasing brown fat, Cohen says there isn’t a good answer to that yet, but it will be a major area of research exploration in the near future. For example, a study published in Cell Metabolism last year highlighted the discovery of a receptor that activates BAT, which could be a step forward for finding ways to turn that receptor on more easily.

What is known is that babies tend to have higher amounts than adults, with BAT representing about 5% of their body mass, likely as a way to keep them warm. Because of their immature nervous systems, less body hair, and less muscular development, newborns can’t shiver as a way to warm themselves, so it’s thought that brown fat helps them regulate heat. As we age, we naturally lose a large store of this fat.

In both newborns and adults, brown fat is located along the upper part of the spine and shoulders. For instance, in the recent study, researchers looked at the necks and cervical spines of those who were scanned to determine prevalence of brown fat.

Because it is located deep in the tissues, it’s impossible to “see” it without that kind of imaging, which means individuals can’t get an idea of how much they have, if any, through observation. That differs from white fat, especially around the abdomen, which is all too easy to recognize.

How to Get More Brown Fat

Even without knowledge of your BAT amount, there are some strategies that have been shown to increase brown fat in general, according to Candice Seti, PsyD, a clinical psychologist who specializes in weight loss and nutrition coaching.

The main way, she says, is through strategic cold exposure. "Because the body will `turn on' your thermogenic response to get warm, this can switch you into using your brown fat, and possibly developing more of it over time," Seti notes.

The cold increases vitamin A levels, a study published in Molecular Metabolism found, and this helps the conversion process from white fat to brown fat. However, there’s no evidence that you can find a shortcut here—vitamin A supplements were not shown to have the same effect.

Another tactic is to eat enough to feel satiated, since hunger can prevent brown fat from activating, she adds. Research on mice published in Cell found that brown fat interacts with a specific hormone in the digestive system to signal fullness to the brain.

Exercise is an additional, highly effective way to turn on brown fat, Seti adds.

“This one should be a no-brainer as it’s on the list for everything health related,” she says. “But this may be beneficial here because of an enzyme called irisin. This enzyme is released when we exercise and it has been shown to convert white fat cells to brown.”