Objective: The gastrointestinal tract plays a key role in feelings of satiation. It is known that there is a reciprocal interaction between the stomach and intestine, but it is not known which factors are of gastric origin and which are intestinal. This three-step study therefore sought to provide illumination on satiation parameters with respect to body mass.
Method: In the first part, the time needed to reach maximal satiation and total caloric intake was calculated after participants (20 normal weight, 20 obese) imbibed a standardized nutrient drink. In the second part gastric emptying of solids and liquids was evaluated using the (13)C-breath test (participants: 16 normal weight, 9 obese for gastric emptying of solids; 15 normal weight, 14 obese for gastric emptying of liquids). And in the third part, fasting and post-prandial plasma glucagon-like peptide-1 (GLP-1), peptide tyrosine tyrosine (PYY) and ghrelin levels were measured after a standardized nutrient drink (participants: 20 normal weight, 20 obese).
Results: Our results show that, when compared to those of normal weight, obese participants reached maximal satiation sooner (P=0.006), their total intake of calories was higher (P=0.013), and their gastric emptying rates were delayed (P<0.001). Furthermore, their post-prandial increase in plasma GLP-1 and PYY was reduced, (P<0.001 for both), as was their ghrelin suppression (P=0.001).
Discussion: We conclude that, in obese subjects gastric emptying can be impaired with delayed interaction of nutrients with the intestine resulting in decreased GLP-1 and PYY secretion. This could imply that obese participants would require more calories before their maximal satiation is reached and they stop eating.
Trial registration: ClinicalTrials.gov NCT01456572.
Keywords: Gastric emptying; Ghrelin; Glucagon-like peptide-1 (GLP-1); Peptide tyrosine tyrosine (PYY); Stomach.
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