It may be time to learn to be a little more open-minded about fat, at least brown fat. Brown fat is the kind of fat you actually want. It burns excess calories by converting chemical energy into heat. White fat cells, in contrast, store energy in lipid droplets that contribute to inflammation and obesity.
The hope is that brown fat can play a role in the treatment of obesity. But because brown fat is often hidden deep within the body and at the moment can only be seen using positron emission tomography (PET) scans, we don’t know if people with more brown fat are actually healthier than those with less brown fat.
Strong evidence for the health benefits of brown fat comes from a new study. In more than 52,000 patients, the presence of brown fat reduced the risk of type 2 diabetes and abnormal cholesterol levels, or dyslipidemia.
Brown fat reduced the risk of hypertension, coronary artery disease, cerebrovascular disease and congestive heart failure. It also seemed to offset the changes in blood glucose and triglycerides associated with obesity.
Surprisingly, brown fat also seemed to offset the changes in blood glucose and triglycerides associated with obesity. And high-density lipoprotein (HDL, or good) cholesterol levels were the same for those who were obese and those with a lower body mass index. “The size of our study allowed us to document associations that hadn’t been reported before, such as a link between brown fat and type 2 diabetes, hypertension, coronary artery disease and congestive heart failure,” Paul Cohen, corresponding author on the study, told TheDoctor.
The study, by researchers at Rockefeller University and Sloan-Kettering Memorial Cancer Center in New York City, reveals associations between brown fat and these health issues. It does not prove a direct cause and effect relationship, Cohen explained. “We cannot say at this point that brown fat prevents type 2 diabetes or coronary artery disease. That will require further prospective interventional studies.”
Many questions about brown fat remain to be answered, said Cohen, the head of the laboratory of molecular metabolism at Rockefeller University and the Albert Resnick, M.D. Assistant Professor there. He and his colleagues hope to see if the presence of brown fat influences the presence and distribution of white fat, and if that association explains some of the benefits seen in the current study.
The Rockefeller researchers are using the large data set from the current study to also look at the association between different drugs and brown fat in order to identify medications that could potentially be repurposed to activate brown fat. One of them, mirabegron (brand name Myrbetriq), a drug approved for the treatment of overactive bladder, has been shown in small studies to activate brown fat.
You may be able to improve your own brown fat deposits. Coffee, fruit, exercise and stimulating environments have all been shown to be positively associated with an increase in brown fat, though their precise relationships to metabolic health are not yet fully proven.
The study is published in Nature Medicine.