Brown adipose tissue as nutrient buffer through diet-induced thermogenesis

Claudine Netzhammer; Jael Senn; Giorgio Morandi; Aninja Isenrich; Christian Wolfrum; Matthias Betz; Laila Fuchtbauer

doi:10.1530/endoabs.110.RC15.6

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Endocrine Abstracts (2025) 110 RC15.6 | DOI: 10.1530/endoabs.110.RC15.6

ECEESPE2025 Rapid Communications Rapid Communications 15: Metabolism, Nutrition and Obesity (6 abstracts)

Brown adipose tissue as nutrient buffer through diet-induced thermogenesis

Claudine Netzhammer ¹ , Jael Senn ¹ , Giorgio Morandi ¹ , Aninja Isenrich ¹ , Christian Wolfrum ² , Matthias Betz ¹ & Laila Füchtbauer ¹

Author affiliations

¹Department of Endocrinology, Diabetes & Metabolism, University Hospital Basel, Basel, Switzerland; ²Department Laboratory of Translational Nutrition Biology, IFNH, ETH Zürich, Schwerzenbach, Switzerland

JOINT2752

Background : Brown adipose tissue (BAT) dissipates energy into heat when activated, classically after cold exposure. While there is clear evidence for the correlation between the presence of active BAT and a lean phenotype as well as lower prevalences of cardiometabolic diseases the exact mechanisms of these beneficial effects remain unclear. Especially, since BAT contribution to the total energy expenditure is small. In this study we test the hypothesis that BAT operates as a nutrient buffer and prevents unfavourable postprandial peaks of glucose, free fatty acids, or branched-chain amino acids.

Objective: The primary objective is to compare postprandial increases of metabolites in subjects with functional BAT to those without. Moreover, we assess how the beforementioned macronutrients and BAT-activity contribute to diet-induced thermogenesis (DIT).

Methods: This single center prospective observational study involves 30 healthy, normal weight volunteers and will be completed by May 2025. Participants are screened for presence or absence of cold induced BAT activity by a mild cold stimulus over two hours, followed by a 18F-FDG-PET/CT. BAT metabolic volume (BMV=SUVmean x BAT volume)>200 ml was chosen as cut-off value to discriminate between BAT-positive and BAT-negative subjects. At each of the following study visits the participants consume an iso-caloric test meal containing exclusively either carbohydrate, protein, or fat. We perform indirect calorimetry hourly and blood samples half-hourly before and during five hours after the test meal.

Results: At the ECE we will present the first analysis of the complete study. Preliminary data of 22 subjects, 10 BAT-positive (BMV=562.10±210.11 ml), 12 BAT-negative (BMV= 79.18±29.84 ml) show no DIT after intake of fat. A 15-20% increase in energy expenditure was observed persistently for at least 5 hours after intake of protein and for 3-4 hours after glucose. No difference was seen between BAT-positive and BAT-negative subjects in this respect. The average fasting blood glucose level of all study visits was 4.92±0.38mmol/l with no difference between the groups. While all had similar glucose curves after the 100g OGTT, we see consistently lower blood glucose values in BAT-positive subjects following the challenge with fat and protein.

Conclusion: Our data show the impact of different macronutrients on DIT and contradict the notion that BAT status has an impact on DIT. Interestingly blood glucose seems to be lower in BAT-positive subjects after intake of protein and fat while glucose tolerance in our healthy subjects does not correlate to BAT status.