O155 Effects of oral feeding on gastric emptying and gastrointestinal hormone secretion in males with obesity compared with those of healthy weight

Abstract

Abstract Introduction Hormones released in response to nutrients in the gastrointestinal (GI) tract, act as physiological signals to regulate appetite and play a role in feeding behaviours. Altered secretion of these ‘appetite’ hormones after feeding in those with obesity (‘Obese’), compared to those with healthy weight (‘Lean’), may drive over-consumption of energy. This study assessed whether gastric emptying rate was implicated in this altered response. Methods Twenty healthy males attended the laboratory once in the morning after an overnight fast. Volume of gastric contents (GCV) and small bowel water (SBW) were assessed using MRI (Philips 3T Ingenia and dStream Anterior Coil) pre, immediately post and every 30-minutes for 4-hours after a standard meal (2.5MJ, 78g Carbohydrate, 24g Protein, 21g Fat). Concurrently, arterialised-venous blood was taken for insulin, ghrelin, GLP-1 and PYY evaluation. Gastric emptying (T50) was derived from GCV. Data are presented as the mean (SD) or standardised effect size (ηp2). Results 10 Lean [38(14)y, 24(2) kg/m2] and 10 Obese [38(13)y, 34(3)kg/m2] were studied. Fasting insulin [12.5(5.8) vs. 17.6(11.3) mIU/l], Ghrelin [3.2(2.1) vs. 2.9(0.9) ng/ml], GLP-1 [7.2(11.5) vs. 13.3(2.5) pmol/l], PYY [102.3(46.7) vs. 88.4(32.4)pg/ml], SBW [121(96) vs. 168(125)ml] and GCV [59(33) vs. 59(30)ml] did not differ between ‘Lean’ and ‘Obese’. Response of Ghrelin (ηp2=0.005), GLP-1 (ηp2=0.103), PYY (ηp2=0.050) and SBWC (ηp2=0.145) to eating, and T50 [148(51) vs. 170(49) min] did not differ between groups. However, postprandial insulin secretion was greater in obese (ηp2=0.286; P<0.05). Conclusion Gastric emptying and incretin hormone secretion were not altered in participants with obesity. However, postprandial hyperinsulinemia, associated with insulin resistance, was observed.