Bitter taste and polyphenols; beneficial physiological activity via gastrointestinal hormones

Recently, there has been a notable emphasis on the homeostatic regulation by taste receptors that are expressed in extra-oral cavities. Bitter receptors (type 2 taste receptors, T2Rs) are abundant in the lower gastrointestinal tract and activated by bitter compounds in food. Activation of T2R triggers the release of gastrointestinal hormones such as cholecystokinin (CCK) or incretin as glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). These peptides regulate appetite and amount of food consumption by affecting gastrointestinal motility. Besides, incretins are also known to regulate blood glucose homeostasis through insulin secretion. Polyphenols are micronutrients commonly found in plant-based food that possess a strong bitter taste. Additionally, they are not well absorbed by the upper digestive tract and thus tend to move to the colon and get excreted in the feces. Previous epidemiological and intervention studies suggest a negative correlation between polyphenol intake and the risk of diabetes. The beneficial functions that follow the ingestion of polyphenols might be caused by the mediation of T2R, which regulates glucose tolerance and gastrointestinal motility. This review explores the relationship between bitter taste and polyphenol bioactivity to understand better the mechanisms by which polyphenols exert their health benefits.

近期，对存在于额外口腔腔隙中的味觉受体所介导的稳态调节的关注度显著提升。苦味受体（第2型味觉受体，T2Rs）在消化道下部尤为丰富，并能被食物中的苦味化合物激活。T2R的激活会引发胆汁酸刺激素（CCK）或肠促胰岛素（如葡萄糖依赖性胰岛素分泌肽GIP和胰高血糖素样肽-1，GLP-1）等胃肠道激素的释放。这些肽类物质通过影响胃肠道运动来调节食欲和食物摄入量。此外，肠促胰岛素还通过胰岛素分泌调节血糖稳态。多酚是植物性食品中常见的微量营养素，具有强烈的苦味。此外，它们在消化道的吸收并不充分，因此倾向于进入结肠并在粪便中排出。既往的流行病学和干预性研究表明，多酚摄入量与糖尿病风险之间存在负相关性。摄入多酚后产生的有益功能可能是由T2R介导的，T2R能够调节葡萄糖耐受性和胃肠道运动。本综述旨在探讨苦味与多酚生物活性之间的关系，以更好地理解多酚发挥健康益处的机制。