A new large study has provided strong evidence that people with brown fat in their bodies are less likely to suffer from a number of health conditions.
“For the first time, it reveals a link to the lower risk of certain conditions,” says one of the researchers, Rockefeller University Hospital physician Paul Cohen.
These findings make us more confident about the potential for targeting brown fat for therapeutic benefit.
Brown fat or brown adipose tissue (BAT) is especially common in hibernating mammals and newborns. BAT helps mammals regulate temperature – when we are really cold, the large amounts of mitochondria found in this type of adipose tissue burn energy and produce heat. In fact, iron-rich mitochondria are what give brown fat its characteristic color.
It was not until 2009 that scientists discovered that some adults also have brown fat in their bodies, usually around the neck and shoulders.
There have been a lot of studies in mice on the benefits of having brown fat, but in humans the research has been more troubled until recently. Having brown fat seems to improve a person’s metabolism and can even help with weight loss (although the latter is probably not as simple).
“The natural question everyone has is,“ What can I do to get more brown fat? “Cohen says.
“We don’t have a good answer to that yet, but it will be an interesting space for scientists to explore in the coming years.”
Looking at a large data set of 52,487 participants undergoing PET / CT scans for cancer, the team found evidence of brown fat in just under 10% of cases (5,070 people).
The researchers believe that this could be an underestimation due to the conditions in which the participants were under – told to avoid exposure to cold, exercise and caffeine before the scans, all of which were related to the activity of brown fat.
About 4.6% of those with brown fat also had type 2 diabetes, while this number was 9.5% in the “no brown fat” group. A similar result was observed in abnormal cholesterol results – 18.9% of people with brown fat had abnormal cholesterol, compared to 22.2% of people who did not have brown fat.
Hypertension, congestive heart failure and coronary artery disease also saw small positive differences in brown fat groups compared to lack of brown fat.
These findings were supported by improved levels of high blood sugar, triglycerides and lipoproteins, the team writes in their new paper.
Although the figures here are exciting, there is still no evidence that brown fat makes you immune to any of these conditions – but there is a link to the low risk that is worth further exploring.
What was really interesting was that brown fat was especially protective for the obese. Those obese patients who had brown fat had a similar prevalence of these metabolic and heart conditions as people who were not obese.
“They seem to be protected from the harmful effects of white fat,” says Cohen.
Taken together, our findings highlight a potential role for BAT in promoting cardiometabolic health, the researchers note in their paper.
It is important to note that the data the researchers worked with came from cancer assessments at the Memorial Sloan Kettering Cancer Center, which means that this is not a representative sample for the general population.
However, the study took a fascinating new look at the role of brown fat in the human body and hopefully will lead to more discoveries in the future.
“We’re considering the possibility of brown fat tissue doing more than consuming glucose and burning calories, and it’s probably actually involved in hormonal signaling to other organs,” says Cohen.
The research was published in Nature medicine.