A large new study has provided strong evidence that people with brown fat in their bodies are less likely to suffer from a range of health problems.
“For the first time, it reveals a link to reducing the risk of certain conditions,” said one of the researchers, the doctor at Rockefeller University Hospital Paul Cohen.
“These findings make us more confident about the potential to target brown fat for therapeutic benefits.”
Brown fat or brown adipose tissue (BAT) is particularly common in mammals and newborns in hibernation. BAT helps mammals to 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, it is the iron-rich mitochondria that give brown fat its characteristic color.
It wasn’t until 2009 that scientists discovered that some adult humans also have brown fat on their bodies, usually around the neck and shoulders.
There have been many studies in mice examining the benefits of having brown fat, but in humans the research was more obscure until recently. Having brown fat seems to improve a person’s metabolism and can even help you lose weight (although the latter is probably not that simple).
“The natural question that everyone has is, ‘What can I do to get more brown fat?'” Says Cohen.
“We don’t have a good answer for that yet, but it will be a stimulating space for scientists to explore in the years to come.”
Looking at a large data set of 52,487 participants who underwent PET / CT scans for cancer assessment, the team found evidence of brown fat in just under 10 percent of cases (5,070 people).
The researchers think this may be an underestimation because of the conditions the participants were in – they were instructed to avoid exposure to cold, exercise and caffeine before the exams, all related to the activity of brown fat.
About 4.6% of people with brown fat also had type 2 diabetes, while that number was 9.5% in the “no brown fat” group. A similar result was seen in abnormal cholesterol results – 18.9% of people with brown fat had abnormal cholesterol, compared with 22.2% of people who did not have brown fat.
Hypertension, congestive heart failure and coronary artery disease also observed small positive differences in the brown fat versus brown fat groups.
“These findings were supported by better blood glucose, triglyceride and high-density lipoprotein values,” writes the team in their new article.
While the numbers here are exciting, there is still no evidence that brown fat makes you immune to any of these conditions – but there is a risk reduction link that is worth exploring further.
What was really interesting is that brown fat was particularly protective in those who were obese. Obese patients who had brown fat had a similar prevalence of these metabolic and cardiac conditions to those who were not obese.
“It almost looks like they are protected from the harmful effects of white fat,” says Cohen.
“Together, our results highlight a potential role for BAT in promoting cardiometabolic health,” the researchers note in their article.
It is important to note that the data the researchers were working with came from cancer assessments at the Memorial Sloan Kettering Cancer Center, which means that this is not a representative sample of the general population.
However, the study yielded a fascinating new look at the role of brown fat in the human body and, hopefully, will lead to even more discoveries in the future.
“We are considering the possibility that the brown adipose tissue does more than consume glucose and burn calories, and perhaps it actually participates in hormonal signaling to other organs,” says Cohen.
The research was published in Nature Medicine.