{
  "abstract": "Introduction The gastrointestinal (GI) tract sense luminal nutrients via specialised enteroendocrine cells that secrete gut hormones, including glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) which play key roles in regulating glucose homeostasis, appetite and energy intake. It remains unclear which macronutrients most effectively stimulate gut hormone secretion at specific GI regions in humans. This systematic review and meta-analysis (PROSPERO registration: CRD42024524709) summarised the evidence from human gut infusion trials investigating effects of carbohydrate, protein, and lipids infused into the duodenum on gut hormone, glycaemia, and appetite in healthy adults.Methods PubMed, Scopus, Ovid MEDLINE, and Embase were searched, identifying 2467 articles. 42 articles met eligible criteria. Primary outcomes were iAUC 0–30 min for gut hormones including gastric inhibitory polypeptide (GIP), cholecystokinin (CCK), GLP-1 and PYY. Secondary outcomes included the plasma glucose and insulin responses, subjective appetite ratings, and food intake. Random-effect meta-analyses were performed using standardised mean difference (SMD) and standard errors.Results The duodenum exhibits distinct hormonal profiles in response to different nutrient stimuli ( table 1): glucose infusion stimulated glucose, insulin and GIP, whereas whey protein and amino acids induced a broader peptide response, increasing CCK and the incretins GIP and GLP-1, accompanied increased circulating insulin without hyperglycaemia (effect sizes: GIP SMD = 0.77 [95% CI: 0.21–1.22], GLP-1 SMD = 0.17 [0.01–0.34], CCK SMD = 0.22 [0.07–0.37], insulin SMD = 0.32 [0.17–0.48]; all p < 0.05). Lipid exposure increased CCK and PYY. Macronutrient infusion into the duodenum did not affect appetite within 30 minutes but reduced subsequent food intake.Conclusions These findings highlight the duodenum as a key regulatory site for nutrient-specific gut hormone secretion and support dietary strategies that enhance duodenal protein and amino acid exposure to improve glycaemic control and appetite regulation.Abstract P381 Table 1Summary outcomes of duodenal infusion (ID) of different nutrientsOutcomeID after 30 minutesCarbProteinLipidGLP1ns↑nsCCKns↑↑PYYnsns↑GIP↑↑nsGlucose↑ns↓Insulin↑↑nsSubjective appetite/fullnessnsnsnsEnergy intake↓↓↓Abbreviation: ns: no significant change, ↓: significantly reduce, ↑: significantly increase. P-value of less than 0.05 is considered significant.",
  "authors": [
    {
      "affiliations": [
        "Section of Nutrition, Department of Metabolism, Digestion and Reproduction,Imperial College London, London, United Kingdom"
      ],
      "name": "Le My Anh Nguyen"
    },
    {
      "affiliations": [
        "Section of Nutrition, Department of Metabolism, Digestion and Reproduction,Imperial College London, London, United Kingdom"
      ],
      "name": "Mingzhu Cai"
    },
    {
      "affiliations": [
        "Section of Nutrition, Department of Metabolism, Digestion and Reproduction,Imperial College London, London, United Kingdom"
      ],
      "name": "Yucen Wu"
    },
    {
      "affiliations": [
        "Section of Nutrition, Department of Metabolism, Digestion and Reproduction,Imperial College London, London, United Kingdom"
      ],
      "name": "Aaron Lett"
    },
    {
      "affiliations": [
        "Section of Nutrition, Department of Metabolism, Digestion and Reproduction,Imperial College London, London, United Kingdom"
      ],
      "name": "Gary Frost"
    }
  ],
  "title": "P381 Effects of duodenal macronutrient infusion on gut hormones, glycaemia, and appetite: a systematic review and meta-analysis",
  "uid": "a3665a46-8864-50a1-bbb6-cb3a4cd1026d"
}