Augmented gut hormone response to feeding in older adults exhibiting low appetite

Abstract

ABSTRACTAge-related changes in gut hormones may play a role in anorexia of ageing. The aim of this study was to determine concentrations of ghrelin, PYY, and GLP-1 in older adults exhibiting an anorexia of ageing phenotype. Thirteen older adults with healthy appetite (OA-HA; 8f, 75±7 years, 26.0±3.2 kg·m-2), fifteen older adults with low appetite (OA-LA; 10f, 72±7 years, 23.6±3.1 kg·m-2), and twelve young adults (YA; 6f, 22±2 years, 24.4±2.0 kg·m-2) completed the study. Healthy appetite and low appetite were determined based on BMI, habitual energy intake, self-reported appetite, and laboratory-assessedad libitumlunch intake. Participants provided a fasted measure of subjective appetite and blood sample (0 minutes) before consuming a standardised breakfast (450 kcal). Appetite was measured every 30 minutes for 240 minutes and blood was sampled at 30, 60, 90, 120, 180 and 240 minutes. At 240 minutes, anad libitumlunch meal was consumed. Relative energy intake at lunch (expressed as percentage of estimated total energy requirement) was lower for OA-LA (19.8±7.7%) compared with YA (41.5±9.2%,p<0.001) and OA-HA (37.3±10.0%,p<0.001). Ghrelin suppression was greater for OA-LA than YA at 90 minutes (−512±477 pg·mL-1vs. 174±182 pg·mL-1,p=0.045)and 180 minutes (−502±147 pg·mL-1vs. −208±202 pg·mL-1,p=0.049), and lower than OA-HA at 60 minutes (−447±447 pg·mL-1vs. −125±169 pg·mL-1,p=0.039). GLP-1 concentration was higher for OA-LA compared with YA at 180 minutes (5.00±4.71 pM vs. 1.07±2.83 pM,p=0.040). Net AUC for PYY response to feeding was greater for OA-LA compared with OA-HA (p=0.052). No differences were seen in subjective appetite. These observations in older adults exhibiting an anorexia of ageing phenotype suggest augmented anorexigenic responses of gut hormones to feeding may be causal mechanisms of anorexia of ageing.