title: Acute load-dependent effects of oral whey protein on gastric emptying, gut hormone release, glycemia, appetite, and energy intake in healthy men.
abstract: BACKGROUND
  In healthy individuals, intraduodenal whey protein load-dependently modulates gastrointestinal motor and hormonal functions and suppresses energy intake. The effect of oral whey, particularly the impact of load, has not been evaluated.
  
  
  OBJECTIVE
  The purpose of this study was to quantify gastric emptying of 30 and 70 g of oral whey protein loads and their relation to gastrointestinal hormone, glycemic, and appetitive responses.
  
  
  METHODS
  On 3 separate occasions in a randomized, double-blind order, 18 lean men [mean ± SEM age: 24.8 ± 1.4 y; body mass index (in kg/m(2)): 21.6 ± 0.5] received iso-osmolar, equally palatable drinks (∼450 mL) containing 30 g pure whey protein isolate (L), 70 g pure whey protein isolate (H), or saline (control). Gastric emptying (with the use of 3-dimensional ultrasound), plasma cholecystokinin, glucagon-like peptide 1, glucose-dependent insulinotropic peptide, insulin, glucagon, total amino acids, and blood glucose were measured for 180 min after consumption of the drinks, and energy intake at a buffet-style lunch was quantified.
  
  
  RESULTS
  Gastric emptying of the L and H drinks was comparable when expressed in kilocalories per minute (L: 2.6 ± 0.2 kcal/min; H: 2.9 ± 0.3 kcal/min) and related between individuals (r = 0.54, P < 0.01). Gastrointestinal hormone, insulin, and glucagon responses to the L and H drinks were comparable until ∼45-60 min after ingestion, after which time the responses became more differentiated. Blood glucose was modestly reduced after the H drink between t = 45 and 150 min when compared with the L drink (all P < 0.05). Energy intake was suppressed by both L and H drinks compared with control (P < 0.05) (control: 1174 ± 91 kcal; L: 1027 ± 81 kcal; and H: 997 ± 71 kcal).
  
  
  CONCLUSIONS
  These findings indicate that, in healthy lean men, the rate of gastric emptying of whey protein is independent of load and determines the initial gastrointestinal hormone response. This study was registered at www.anzctr.org.au as 12611000706976.
authors.affiliation: University of Adelaide Discipline of Medicine, Royal Adelaide Hospital, Adelaide, Australia; National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia;
authors.forename: Amy T
authors.identifier: http://orcid.org/0000-0002-6393-3671
authors.initials: AT
authors.lastname: Hutchison
authors.affiliation: University of Adelaide Discipline of Medicine, Royal Adelaide Hospital, Adelaide, Australia; School of Health Sciences and.
authors.forename: Diana
authors.initials: D
authors.lastname: Piscitelli
authors.affiliation: University of Adelaide Discipline of Medicine, Royal Adelaide Hospital, Adelaide, Australia; National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia;
authors.forename: Michael
authors.initials: M
authors.lastname: Horowitz
authors.affiliation: University of Adelaide Discipline of Medicine, Royal Adelaide Hospital, Adelaide, Australia; National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia;
authors.forename: Karen L
authors.initials: KL
authors.lastname: Jones
authors.affiliation: University of Adelaide Discipline of Medicine, Royal Adelaide Hospital, Adelaide, Australia; National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia; School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia;
authors.forename: Peter M
authors.initials: PM
authors.lastname: Clifton
authors.affiliation: University of Adelaide Discipline of Medicine, Royal Adelaide Hospital, Adelaide, Australia; National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia;
authors.forename: Scott
authors.initials: S
authors.lastname: Standfield
authors.affiliation: Institute of Medicine, University of Bergen, and National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway; and.
authors.forename: Trygve
authors.initials: T
authors.lastname: Hausken
authors.affiliation: University of Adelaide Discipline of Medicine, Royal Adelaide Hospital, Adelaide, Australia; National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia;
authors.forename: Christine
authors.identifier: http://orcid.org/0000-0001-6848-0125
authors.initials: C
authors.lastname: Feinle-Bisset
authors.affiliation: University of Adelaide Discipline of Medicine, Royal Adelaide Hospital, Adelaide, Australia; National Health and Medical Research Council Centre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia; Food and Nutrition Flagship, Commonwealth Science and Industrial Research Organization, Adelaide, Australia natalie.luscombe-marsh@csiro.au.
authors.forename: Natalie D
authors.identifier: http://orcid.org/0000-0001-9690-4722
authors.initials: ND
authors.lastname: Luscombe-Marsh
mesh_terms: D000293:Adolescent; D000328:Adult; D001069:Appetite Regulation; D001628:Beverages; D001786:Blood Glucose / Q000032:analysis; D062408:Breakfast; D002766:Cholecystokinin / Q000097:blood / Q000378:metabolism; D018592:Cross-Over Studies; D004311:Double-Blind Method; D002149:Energy Intake; D005746:Gastric Emptying; D005749:Gastric Inhibitory Polypeptide / Q000097:blood / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism*; D005934:Glucagon / Q000097:blood / Q000378:metabolism; D052216:Glucagon-Like Peptide 1 / Q000097:blood / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism; D000078790:Insulin Secretion; D062409:Lunch; D008297:Male; D019518:Postprandial Period; D000067816:Whey Proteins / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D007328:Insulin; D000067816:Whey Proteins; D005749:Gastric Inhibitory Polypeptide; D052216:Glucagon-Like Peptide 1; D005934:Glucagon; D002766:Cholecystokinin
keywords: dairy protein; food intake regulation; gastrointestinal; glycemic control; gut function; humans; obesity; weight management