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517184 
Journal Article 
Intestinal absorption of water-soluble vitamins: an update 
Said, HM; Mohammed, ZM 
2006 
Yes 
Current Opinion in Gastroenterology
ISSN: 0267-1379
EISSN: 1531-7056 
22 
2 
140-146 
English 
Purpose of review The molecular biology revolution has led to a significant improvement in our understanding of biological and physiological processes. Such expansion of knowledge has also covered the field of intestinal absorption of water-soluble vitamins and is the subject of this review. Recent findings Impressive progress has been made in the understanding of the mechanisms and regulation of transport of water-soluble vitamins at the cellular and molecular levels. In addition, the 5' regulatory regions of the genes that encode a number of the involved transporters have been cloned and characterized in vitro and in vivo in transgenic mice, thus providing important information about transcriptional regulation of these events. Furthermore, confocal imaging of live intestinal epithelial cells has led to significant progress in understanding the mechanisms involved in intracellular trafficking and membrane targeting of the carrier proteins and how clinical mutations lead to interference with transport. Finally, the identification in the large intestine of efficient and specialized carrier-mediated systems that are capable of absorbing a number of the bacterially synthesized vitamins (thiamin, folate, biotin, riboflavin, pantothenic acid) has raised the possibility that this source of vitamins may play a role in regulating (fine tuning) the normal body homeostasis of these vitamins, and especially the vitamin level in the local colonocytes. Summary Water-soluble vitamin absorption involves regulated and specific mechanisms. Interference with the function of these mechanisms may lead to deficiency. The large intestine is capable of absorbing water-soluble vitamins that are synthesized by the normal microflora. 
ascorbic acid; biotin; cobalamin; folate; intestinal absorption; niacin; pantothenic acid; pyridoxine; riboflavin; thiamin; transport; mechanism; transport regulation; water-soluble vitamins; dependent multivitamin transporter; membrane targeting mechanisms; megaloblastic-anemia syndrome; epithelial ncm460 cells; folate; transport; biotin transport; caco-2 cells; intracellular trafficking; 5'-regulatory region; molecular-mechanism