Beate Ott1,2, Thomas Skurk1,2, Llias Lagkouvardos2, Sandra Fischer2, Janine Büttner3, Martina Lichtenegger4, Thomas Clavel2,5, Andreas Lechner6,7,8, Michael Rychlik4, Dirk Haller2,9, Hans Hauner1,2,10. 1. Else Kröner-Fresenius-Center of Nutritional Medicine, ZIEL Institute for FOOD and Health, Chair of Analytical Food Chemistry, and Chair of Nutrition and Immunology, Technical University of Munich, Freising, Germany. 2. ZIEL Institute for FOOD and Health, Chair of Analytical Food Chemistry, and Chair of Nutrition and Immunology, Technical University of Munich, Freising, Germany. 3. Charité-Universitätsmedizin, Medizinische Klinik mit Schwerpunkt Hepatologie und Gastroenterologie, Berlin, Germany. 4. Chair of Analytical Food Chemistry, and Chair of Nutrition and Immunology, Technical University of Munich, Freising, Germany. 5. Institute of Medical Microbiology, RWTH University Hospital, Aachen, Germany. 6. Diabetes Research Group, Medical Department 4, Ludwig-Maximilians Universität, Munich, Germany. 7. Clinical Cooperation Group Type 2 Diabetes, German Research Center for Environmental Health, Neuherberg, Germany. 8. Diabetes Research Group, German Center for Diabetes Research, Munich, Germany. 9. Chair of Nutrition and Immunology, Technical University of Munich, Freising, Germany. 10. Institute of Nutritional Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.
Abstract
Background: High-fat diets (HFDs) have been linked to low-grade inflammation and insulin resistance. Objective: The main purpose of the present study was to assess whether acute overfeeding with an HFD affects insulin sensitivity, gut barrier function, and fecal microbiota in humans. Methods: In a prospective intervention study, 24 healthy men [mean ± SD: age 23.0 ± 2.8 y, body mass index (in kg/m2) 23.0 ± 2.1] received an HFD (48% of energy from fat) with an additional 1000 kcal/d (as whipping cream) above their calculated energy expenditure for 7 d. Insulin sensitivity (hyperinsulinemic euglycemic clamp), gut permeability (sugar and polyethylene glycol absorption tests, plasma zonulin), and gut microbiota profiles (high-throughput 16S rRNA gene sequencing) were assessed before and after overfeeding, and 14 d after intervention. Additionally, inflammation markers such as high-sensitivity C-reactive protein, lipopolysaccharide-binding protein, leptin, high-molecular-weight adiponectin, calprotectin, regulated on activation normal, T cell expressed and secreted (RANTES), and monocyte chemoattractant protein-1 were measured in plasma by ELISA. Finally, lipid parameters were analyzed in serum by a laboratory service. Results: Although participants gained 0.9 ± 0.6 kg (P < 0.001) body weight, overnutrition was not associated with a significant change in insulin sensitivity (M value and glucose disposal). Overfeeding for 7 d resulted in elevated serum total (10.2%), LDL (14.6%) and HDL (14.8%) cholesterol concentrations (P < 0.01). In contrast, fasting plasma triglyceride significantly declined (29.3%) during overfeeding (P < 0.001). In addition, there were no significant changes in inflammatory markers. Urine excretion of 4 sugars and polyethylene glycol, used as a proxy for gut permeability, and plasma concentration of zonulin, a marker of paracellular gut permeability, were unchanged. Moreover, overfeeding was not associated with consistent changes in gut microbiota profiles, but marked alterations were observed in a subgroup of 6 individuals. Conclusions: Our findings suggest that short-term overfeeding with an HFD does not significantly impair insulin sensitivity and gut permeability in normal-weight healthy men, and that changes in dominant communities of fecal bacteria occur only in certain individuals. The study was registered in the German Clinical Trial Register as DRKS00006211.
Background: High-fat diets (HFDs) have been linked to low-grade inflammation and insulin resistance. Objective: The main purpose of the present study was to assess whether acute overfeeding with an HFD affects insulin sensitivity, gut barrier function, and fecal microbiota in humans. Methods: In a prospective intervention study, 24 healthy men [mean ± SD: age 23.0 ± 2.8 y, body mass index (in kg/m2) 23.0 ± 2.1] received an HFD (48% of energy from fat) with an additional 1000 kcal/d (as whipping cream) above their calculated energy expenditure for 7 d. Insulin sensitivity (hyperinsulinemic euglycemic clamp), gut permeability (sugar and polyethylene glycol absorption tests, plasma zonulin), and gut microbiota profiles (high-throughput 16S rRNA gene sequencing) were assessed before and after overfeeding, and 14 d after intervention. Additionally, inflammation markers such as high-sensitivity C-reactive protein, lipopolysaccharide-binding protein, leptin, high-molecular-weight adiponectin, calprotectin, regulated on activation normal, T cell expressed and secreted (RANTES), and monocyte chemoattractant protein-1 were measured in plasma by ELISA. Finally, lipid parameters were analyzed in serum by a laboratory service. Results: Although participants gained 0.9 ± 0.6 kg (P < 0.001) body weight, overnutrition was not associated with a significant change in insulin sensitivity (M value and glucose disposal). Overfeeding for 7 d resulted in elevated serum total (10.2%), LDL (14.6%) and HDL (14.8%) cholesterol concentrations (P < 0.01). In contrast, fasting plasma triglyceride significantly declined (29.3%) during overfeeding (P < 0.001). In addition, there were no significant changes in inflammatory markers. Urine excretion of 4 sugars and polyethylene glycol, used as a proxy for gut permeability, and plasma concentration of zonulin, a marker of paracellular gut permeability, were unchanged. Moreover, overfeeding was not associated with consistent changes in gut microbiota profiles, but marked alterations were observed in a subgroup of 6 individuals. Conclusions: Our findings suggest that short-term overfeeding with an HFD does not significantly impair insulin sensitivity and gut permeability in normal-weight healthy men, and that changes in dominant communities of fecal bacteria occur only in certain individuals. The study was registered in the German Clinical Trial Register as DRKS00006211.