Brown fat protects against secondary obesity-related diseases, says study

Recent research headed by Florian Kiefer’s research team from the Division of Endocrinology and Metabolism of the Department of Medicine III at MedUni Vienna and Vienna General Hospital demonstrated that individuals who are seriously overweight (obese) and have active brown fat possess a healthier metabolism and utilize more energy than obese people without brown fat.

Image Credit: Medical University of Vienna.

This suggests that not all forms of obesity are the same and that brown fat can make the difference. The observations indicate that the existence of brown fat might safeguard secondary obesity-related diseases. The research was published in Diabetes, a top international journal.

For many years, medical researchers have been wondering why some obese individuals are less likely to develop health conditions like high blood pressure or diabetes than others of the same weight. Recently, a vital factor called “metabolically healthy obesity” in the form of brown fat has been observed.

Brown fat has long been thought to benefit metabolism because, unlike the much more common white storage fat, it can burn energy in the form of heat. Babies and toddlers, in particular, use brown adipose tissue to maintain their body temperature but the proportion of brown fat in the body decreases with age and with excess weight.”

Florian Kiefer, Division of Endocrinology and Metabolism, Department of Medicine III, Vienna General Hospital

Current research carried out by the Viennese research team identified that more than one-third of gravely overweight adults (BMI > 35 kg/m²) still possess active brown fat. The volunteers were initially exposed to moderate cold employing cooling vests to activate brown fat, which was later examined by PET-CT scanning in the research.

“In adults, brown fat is predominantly found at the base of the neck and in the rib cage. A brief period of cold stimulation of about one hour is sufficient to activate it,” states study author Kiefer.

The overweight participants with brown fat showed a higher energy consumption, healthier sugar metabolism, less harmful abdominal fat, and reduced signs of fatty liver disease compared to a control group of similar weight devoid of detectable brown fat.

It’s quite amazing that the participants with brown fat did better on almost all metabolic parameters, even though they had a slightly higher BMI. These data once again show us that it’s not just the quantity of adipose tissue that matters, but more importantly its quality.”

Florian Kiefer, Division of Endocrinology and Metabolism, Department of Medicine III, Vienna General Hospital

The variations in fat distribution might have assisted in the advantageous metabolic status. Particularly, the percentage of deep-lying abdominal fat (visceral fat), representing a high risk for heart attack and diabetes, was substantially decreased in the brown fat group.

It is conceivable that the increased metabolic activity of brown fat will preferentially break down and burn harmful visceral fat stores first. That is why we are currently working hard to develop drug treatments to activate brown fat.”

Florian Kiefer, Division of Endocrinology and Metabolism, Department of Medicine III, Vienna General Hospital