title: Effects of Fat and Protein Preloads on Pouch Emptying, Intestinal Transit, Glycaemia, Gut Hormones, Glucose Absorption, Blood Pressure and Gastrointestinal Symptoms After Roux-en-Y Gastric Bypass.
abstract: BACKGROUND
  The aim was to determine the effects of fat and protein preloads on pouch emptying (PE), caecal arrival time (CAT), glucose absorption, blood glucose (BSL), gut hormones, haemodynamics and gastrointestinal (GI) symptoms in subjects who had undergone Roux-en-Y gastric bypass (RYGB) >12 months previously.
  
  
  METHODS
  Ten RYGB subjects were studied on three occasions, in randomised order, receiving 200-ml preloads of either water, fat (30 ml olive oil) or whey protein (55 g), 30 min before a mixed meal. PE, CAT, BSL, plasma 3-O-methyl-D-glucopyranose (3-OMG), insulin, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide 1 (GLP-1) and glucagon, blood pressure (BP), heart rate (HR) and GI symptoms were assessed over 270 min.
  
  
  RESULTS
  Although fat and protein preloads did not alter PE of either solids or liquids, the CAT of solids, but not liquids, was longer than that after the water preload (fat 68 ± 5 min and protein 71 ± 6 min vs. water 46 ± 5 min; P = 0.02). BSL elevated promptly after the meal on all days (P < 0.001), but after protein, the magnitude and integrated increases in the first 75 min were less than fat and water preloads (area under the curve (AUC(0-75 min)), 18.7 ± 18.2 vs. 107.2 ± 30.4 and 76.1 ± 19.3 mmol/L/min; P < 0.05). Compared to water preload, the protein and fat preloads were associated with greater increases in plasma insulin, GLP-1 and glucagon concentrations, a reduction in BP, and greater increases in HR, fullness, bloating and nausea. Plasma 3-OMG levels were lower after the protein than after the water and fat preloads (P < 0.001).
  
  
  CONCLUSIONS
  Given its effects to attenuate post-prandial glycaemia, reduce intestinal glucose absorption and potentiate the "incretin response", without inducing more adverse post-prandial GI symptom, protein preload may prove clinically useful in RYGB patients and warrant further evaluation, particularly in those with type 2 diabetes (T2DM) and/or dumping syndrome.
authors.affiliation: Department of Gastroenterology, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia. quoc.nguyen@health.sa.gov.au.|Discipline of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia. quoc.nguyen@health.sa.gov.au.
authors.forename: Nam Q
authors.initials: NQ
authors.lastname: Nguyen
authors.affiliation: Department of Gastroenterology, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia.
authors.forename: Tamara L
authors.initials: TL
authors.lastname: Debreceni
authors.affiliation: Department of Gastroenterology, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia.
authors.forename: Carly M
authors.initials: CM
authors.lastname: Burgstad
authors.affiliation: Department of Gastroenterology, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia.
authors.forename: Melissa
authors.initials: M
authors.lastname: Neo
authors.affiliation: Department of Nuclear Medicine, Royal Adelaide Hospital, Adelaide, SA, 5000, Australia.
authors.forename: Max
authors.initials: M
authors.lastname: Bellon
authors.affiliation: Discipline of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia.
authors.forename: Judith M
authors.initials: JM
authors.lastname: Wishart
authors.affiliation: Discipline of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia.
authors.forename: Scott
authors.initials: S
authors.lastname: Standfield
authors.affiliation: Department of Gastroenterology, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia.|Department of Nuclear Medicine, Royal Adelaide Hospital, Adelaide, SA, 5000, Australia.
authors.forename: Dylan
authors.initials: D
authors.lastname: Bartholomeusz
authors.affiliation: Department of Gastroenterology, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia.|Discipline of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia.
authors.forename: Chris K
authors.initials: CK
authors.lastname: Rayner
authors.affiliation: Discipline of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia.
authors.forename: Gary
authors.initials: G
authors.lastname: Wittert
authors.affiliation: Discipline of Medicine, University of Adelaide, Adelaide, SA, 5000, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Horowitz
mesh_terms: D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure; D004041:Dietary Fats / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage*; D005260:Female; D015390:Gastric Bypass; D005772:Gastrointestinal Transit; D005934:Glucagon / Q000097:blood; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D006339:Heart Rate; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009325:Nausea; D014867:Water
chemical_list: D001786:Blood Glucose; D004041:Dietary Fats; D004044:Dietary Proteins; D007328:Insulin; D014867:Water; D052216:Glucagon-Like Peptide 1; D005934:Glucagon
keywords: Carbohydrate absorption; Fat; Gastrointestinal hormones; Glucose; Post-prandial hyperglycaemia; Preload; Protein; Roux-en-Y gastric bypass