Effects of Lipids on Gastric Emptying, Satiety Hormones, and Appetite in Severe Overweight
Condition: Effects of Lipids on Gastric Emptying; Effects of Lipids on Satiety Hormones; Effects of Lipids on Appetite
MeSH terms: Overweight
Study type: Observational

Summary: 
      In lean subjects, free fatty acid (FFA) promotes gut hormone release, delays gastric
      emptying, and reduces appetite and energy intake more than an isocaloric load of triglyceride
      (TG). In obesity, the gastrointestinal sensitivity to food components may be reduced. In this
      study, the investigators compare the effects of the FFA oleic acid and the TG olive oil on
      gut hormone secretion, gastric emptying, appetite sensation, and subsequent energy intake in
      lean and severely obese subjects.
    

Detailed description: 
      Nutritional lipid within the lumen of small intestine causes a range of physiological
      responses that suppress appetite and reduce energy intake. Thus, intestinal fat promotes the
      release of gastrointestinal hormones such as cholecystokinin (CCK), peptide-YY (PYY) and
      glucagon-like peptide-1 (GLP-1) that modulate gastrointestinal motility and are important for
      appetite regulation and food consumption.

      The effect of ingested fat on gut hormone secretion is highly dependent on the lipolysis of
      triglycerides (TGs) into free fatty acids (FFAs). It has been demonstrated that adding a
      lipase inhibitor (tetrahydrolipstatin) to a pure fat meal accelerates gastric emptying and
      reduces CCK release. Furthermore, administration of tetrahydrolipstatin with an intraduodenal
      infusion of TG attenuates gastric relaxation and antro-pyloro-duodenal motility and reduces
      the release of CCK, PYY, and GLP-1 compared to TG alone. Finally, intragastric administration
      of FFA delays gastric emptying and augments the release of CCK and PYY compared to an
      isocaloric administration of TG. Hence, the presence of FFAs more than TGs within the small
      intestine seem to play a pivotal role in the regulation of appetite and energy intake.

      Whereas acute intake of FFA represents a potent stimulus for suppression of appetite and
      energy intake, epidemiological evidence relates long-term high dietary fat intake with
      obesity and it is known that obese individuals prefer food with high fat content. The
      mechanisms behind this paradox remain unclear. However, sustained high fat-diet may change
      gastromotor responses and gut hormonal release to a dietary load of lipids. Moreover
      intraduodenal sensitivity to FFA (oleic acid) was recently reported to be reduced in obese
      subjects. The reduced appetite and energy intake after FFAs compared to TGs may, therefore,
      not apply to obese subjects.

      The aims of this study are to evaluate gastric emptying, gut hormone secretion, appetite
      sensation, and energy intake after isocaloric gastric administration of FFA (oleic acid) and
      TG (olive oil) in lean and severely obese subjects.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        10 lean subjects and 10 severely obese subjects
      
Biospecimen description: 
      Plasma
    
Keywords: Free fatty acid; Triglyceride; Gastric emptying; Satiety hormones; Appetite; Severe obesity