Effects of intraduodenal lipid and protein on gut motility and hormone release, glycemia, appetite, and energy intake in lean men

Amy Hutchison, Natalie D. Luscombe-Marsh, Alexander A. Saies, Tanya J. Little, Scott Standfield, Michael Horowitz, Christine Feinle-Bisset

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69 Citations (Scopus)


Background: Intraduodenal lipid modulates gastrointestinal motility and hormone release and suppresses energy intake (EI) more than does intraduodenal glucose. Oral protein is the most satiating macronutrient and modulates postprandial glycemia; the comparative effects of intraduodenal protein and lipid and their combined effects are unclear. Objective: We investigated the effects of intraduodenal protein and lipid, alone or in combination, on antropyloroduodenal motility, gastrointestinal hormone release, glycemia, and EI. Design: Twenty lean men were studied on 5 randomized, doubleblind occasions. Antropyloroduodenal motility, cholecystokinin, glucagon-like peptide-1 (GLP-1), insulin, glucagon, blood glucose, appetite, and nausea were measured during 90-min isocaloric (3 kcal/min) intraduodenal infusions of lipid [pure lipid condition (L3)], protein [pure protein condition (P3)], a 2:1 combination of lipid and protein [2:1 lipid:protein condition (L2P1)], a 1:2 combination of lipid and protein [1:2 lipid:protein condition (L1P2)], or a control. Immediately after the infusion, EI from a buffet lunch was quantified. Results: In comparison with the control, all nutrient infusions suppressed antral and duodenal and stimulated pyloric pressures (P <0.05). Cholecystokinin and GLP-1 release and pyloric stimulation were lipid-load dependent (r ≥ 0.39, P < 0.01), insulin and glucagon releases were protein-load dependent (r = 0.83, P < 0.001), and normoglycemia was maintained. L3 but not P3 increased nausea (P < 0.05). Compared with the control, L3 and P3 but not L2P1 or L1P2 suppressed EI (P < 0.05) without major effects on appetite. Conclusions: In lean men, despite differing effects on gut function, intraduodenal lipid and protein produce comparable reductions in energy intake. The effects of lipid may be a result of nausea. Protein also regulates blood glucose by stimulating insulin and glucagon. In contrast, at the loads selected, lipid:protein combinations did not suppress energy intake, suggesting that a threshold load is required to elicit effects.

Original languageEnglish
Pages (from-to)300-311
Number of pages12
JournalAmerican Journal of Clinical Nutrition
Issue number2
Publication statusPublished or Issued - 1 Aug 2013

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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