An extract of hops (Humulus lupulus L.) modulates gut peptide hormone secretion and reduces energy intake in healthy weight men: a randomised, cross-over clinical trial

Abstract

Background: Gastrointestinal enteroendocrine cells express a range of chemosensory receptors involved in detecting the chemical composition of food during digestion. These receptors, including bitter taste receptors (T2Rs), may play an important role in regulating gut function and appetite. Objective: To establish the ability of Amarasate(R), a bitter supercritical CO2 extract of hops (Humulus lupulus L.) to modify acute energy intake, appetite and hormonal responses and establish a site of action. Design: Nineteen healthy-weight (BMI = 23.5 {+/-} 0.3 kg/m2) male volunteers completed a randomised three-treatment, double blind, cross-over study with a 1 week washout between treatments. Overnight-fasted participants were cannulated and provided with a standardised 2 MJ breakfast meal. Treatments comprised a vehicle control (Placebo) or hops extract administered in either quick release (Gastric) or delayed release (Duodenal) capsules. Ad libitum energy intake was recorded at an outcome lunch (1200 h) and afternoon snack (1400 h), with blood samples taken and subjective ratings of appetite, gastrointestinal discomfort, vitality, meal palatability and mood assessed throughout the day. Results: Compared with placebo, both gastric and duodenal treatments significantly reduced total ad libitum energy intake by 911 {+/-} 308 kJ and 944 {+/-} 309 kJ, respectively. Both gastric and duodenal treatments significantly increased pre-meal ghrelin and post-prandial CCK, GLP-1 and PYY responses while reducing postprandial insulin, GIP and PP secretion with no significant impact on glycemia. In addition, gastric and duodenal treatments produced small but significant changes in measures of gastrointestinal discomfort, vitality and mood, with mild-moderate adverse GI symptoms reported in the gastric treatment only. However, no significant treatment effects were observed for any subjective measures of appetite or meal palatability. Conclusion: Both gastric and duodenal delivery of Amarasate modulate the release of hormones involved in appetite and glycaemic regulation, providing a potential bitter brake on energy intake in healthy-weight men.