Summary: A small clinical study finds that short-term exposure to moderate cold activates brown adipose tissue (brown fat) and increases energy expenditure, enabling people with active brown fat to burn roughly 15% more calories—approximately an extra 20 kilocalories—compared with those who lack detectable brown fat.
Source: The Endocrine Society
Short-term cold exposure and brown fat: key findings
New research published in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism shows that short bouts of moderate cold can stimulate brown adipose tissue (BAT) and raise calorie burning in people who have active brown fat. Unlike white fat, which stores energy, BAT consumes fatty acids to generate heat, a process called thermogenesis. Because of this calorie-burning capacity, BAT is of growing interest as a potential target in strategies to prevent and treat obesity and metabolic disease. Moderate cold is the most effective natural trigger known to activate brown fat in humans.
“This data improves our understanding of how brown fat works in humans,” said Florian W. Kiefer, M.D., Ph.D., of the Medical University of Vienna, the study’s corresponding author. The researchers observed that individuals with active BAT expended about 20 kilocalories more during a single cold exposure than those without detectable BAT, which corresponds to an approximate 15% increase in cold-induced calorie burning in this cohort.
Study design and methods
The research team enrolled matched participants who were identified as BAT-positive (BATpos) or BAT-negative (BATneg) using [18F]-FDG PET/CT imaging. To measure brown fat activity and whole-body energy expenditure, investigators combined PET/CT scans with indirect calorimetry before and after short-term cold exposure. They also profiled circulating lipids, including polyunsaturated fatty acids (PUFAs) and oxylipins, using high-resolution mass spectrometry to explore BAT’s influence on systemic lipid mediators.
Results: BAT drives cold-induced energy expenditure and alters lipid profiles
Active brown fat emerged as the principal determinant of cold-induced energy expenditure in this study. Only BATpos participants showed a significant rise in energy expenditure in response to cold, while BATneg individuals did not experience the same increase. In practical terms, a single moderate cold exposure led to about 20 kcal of extra energy dissipation in BAT-positive subjects.
Beyond calorie burning, the presence of active BAT was associated with a distinct circulating lipid signature. BATpos individuals exhibited higher levels of anti-inflammatory omega-3 fatty acids and certain cytochrome P450–derived oxylipins, while some pro-inflammatory hydroxyeicosatetraenoic acids (HETEs) were lower compared with BATneg participants. Notably, levels of specific BAT-related lipid mediators—recently described compounds such as DiHOME and 12-HEPE—rose after cold exposure only in the BATpos group, highlighting BAT’s role not just in thermogenesis but also in systemic lipid regulation and signaling.
Implications
These findings reinforce the concept that human brown fat contributes meaningfully to cold-induced energy dissipation and helps shape the circulating lipidome toward a profile that may be metabolically favorable. The results support further investigation into BAT as a potential protective organ against metabolic and cardiovascular disease and as a therapeutic target to enhance energy expenditure and modify lipid signaling.
Authors and funding
The study was led by Florian W. Kiefer and includes coauthors Oana C. Kulterer, Carsten T. Herz, Alexander R. Haug, Dietmar Pils, and Alexandra Kautzky-Willer (Medical University of Vienna); and Laura Niederstaetter, Andrea Bileck, and Christopher Gerner (University of Vienna). Funding was provided by the Vienna Science and Technology Fund, the Austrian Science Fund, and the Austrian Diabetes Association Research Fund.
About this neuroscience research article
Source:
The Endocrine Society
Media Contacts:
Colleen Williams – The Endocrine Society
Image Source:
The image is in the public domain.
Original Research:
“The presence of active brown adipose tissue determines cold-induced energy expenditure and oxylipin profiles in humans” by Florian W. Kiefer et al., Journal of Clinical Endocrinology & Metabolism. doi: 10.1210/clinem/dgaa183. (Closed access)
Abstract (summary)
Accumulating evidence links BAT to increased cold-induced energy expenditure (CIEE) and to the regulation of lipid metabolism in humans. BAT has been proposed as a source of biologically active lipid mediators including polyunsaturated fatty acids and oxylipins. This study compared individuals with detectable BAT (BATpos) to matched BAT-negative (BATneg) subjects, assessing BAT function, CIEE, and circulating oxylipins before and after short-term cold exposure using [18F]-FDG PET/CT, indirect calorimetry, and high-resolution mass spectrometry. Results indicate that BAT is the primary driver of cold-induced energy expenditure, with BATpos individuals showing significant increases in energy use and a distinct systemic PUFA and oxylipin profile—marked by higher anti-inflammatory ω-3 fatty acids and cytochrome P450 products and lower levels of some pro-inflammatory HETEs. Cold exposure specifically elevated certain BAT-derived lipids, including DiHOME and 12-HEPE, only in BATpos participants. Overall, the data highlight BAT’s role in energy dissipation during cold stress and its importance in shaping systemic lipid pools.
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