UpToDate
Official reprint from UpToDate®
www.uptodate.com ©2016 UpToDate®

Mechanisms of nutrient absorption and malabsorption

Author
Joel B Mason, MD
Section Editor
Timothy O Lipman, MD
Deputy Editor
Shilpa Grover, MD, MPH

INTRODUCTION

Malabsorption refers to impaired absorption of nutrients [1]. It can result from congenital defects in the membrane transport systems of the small intestinal epithelium or from acquired defects in the epithelial absorptive surface. Another factor that can interfere with nutrient absorption is maldigestion, which is due to impaired digestion of nutrients within the intestinal lumen or at the terminal digestive site of the brush border membrane of mucosal epithelial cells.

Although malabsorption and maldigestion are pathophysiologically different, the processes underlying digestion and absorption are interdependent, so that in clinical practice, the term malabsorption has come to denote derangements in either process.

Three steps are required for normal nutrient absorption [2]:

Luminal processing

Absorption into the intestinal mucosa

     

Subscribers log in here

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information or to purchase a personal subscription, click below on the option that best describes you:
Literature review current through: Nov 2016. | This topic last updated: Thu Jun 04 00:00:00 GMT+00:00 2015.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2016 UpToDate, Inc.
References
Top
  1. Hogenauer C, Hammer HF. Maldigestion and Malabsorption. In: Sleisenger and Fordtran's Gastrointestinal and Liver Disease, 10th ed, Feldman M, Friedman LS, Brandt LJ (Eds), Saunders, Philadelphia 2016. p.1788.
  2. Farrell JJ. Digestion and absorption of nutrients and vitamins. In: Sleisenger and Fordtran's Gastrointestinal and Liver Disease, 9th ed, Feldman M, Friedman L, Brandt L (Eds), Saunders, Philadelphia, PA 2010. p.1695.
  3. Shim J, Moulson CL, Newberry EP, et al. Fatty acid transport protein 4 is dispensable for intestinal lipid absorption in mice. J Lipid Res 2009; 50:491.
  4. Abumrad N, Nassir F, Marcus A. Digestion and Absorption of Dietary Fat, Carbohydrate, and Protein. In: Sleisenger and Fordtran's Gastrointestinal and Liver Disease, 10th ed, Feldman M, Friedman LS, Brandt LJ. (Eds), Saunders, Philadelphia 2016. p.1736.
  5. Mansbach CM, Siddiqi SA. The biogenesis of chylomicrons. Annu Rev Physiol 2010; 72:315.
  6. Said H, Trebble T. Intestinal Digestion and Absorption of Micronutrients. In: Sleisenger and Fordtran's Gastrointestinal and Liver Disease, 10th ed, Feldman M, Friedman LS, Brandt LJ. (Eds), Saunders, Philadelphia 2016. p.1765.