Dietary Fiber Pectin is Recognized in a Structure-Specific Manner by Intestinal Cells

Pectin, a natural complex heteropolysaccharide, is a constituent of the cell wall and is conserved in all terrestrial plants. It is composed of galacturonic acid residues and a variety of neutral sugars such as rhamnose, galactose and arabinose. When one eats vegetables or fruits, pectin will be consumed, which will serve as dietary fiber in the body. Dietary fibers perform various physiological and metabolic functions in the human body. Pectin has also been reported to be involved in a number of physiological functions as a water-soluble dietary fiber. Many of them involve the work of secondary metabolites produced by intestinal bacteria as a dietary fiber when reaching the large intestine without being digested or absorbed in the human small intestine, and then further metabolized by intestinal bacteria. Besides the health benefits associated with dietary fibers, new health-related functions of pectin are being explored, particularly those related to the bioactive roles of inducing morphological changes in the small intestine. This review discusses the structure of pectin, its widely known physiological functions, and the possibility that pectin functions not only as a prebiotic but also as a physiologically active substance.