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  • Author: Stephan U Goebel, MD; Chief Editor: Julian Katz, MD  more...
Updated: Dec 16, 2014


Malabsorption is a clinical term that encompasses defects occurring during the digestion and absorption of food nutrients by and infections of the gastrointestinal tract. The digestion or absorption of a single nutrient component may be impaired, as in lactose intolerance due to lactase deficiency. When a diffuse disorder, such as celiac disease or Crohn's disease, affects the intestine, the absorption of almost all nutrients is impaired.

Although presenting symptoms, such as diarrhea and weight loss, may be common, the specific causes of malabsorption are usually established based on physiologic evaluations. The treatment often depends on the establishment of a definitive etiology for malabsorption.



To understand the mechanisms of malabsorption, understanding the normal physiologic process of digestion and absorption by the intestinal tract is necessary.

In general, the digestion and absorption of food materials can be divided into 3 major phases: luminal, mucosal, and postabsorptive.[1] The luminal phase is the phase in which dietary fats, proteins, and carbohydrates are hydrolyzed and solubilized by secreted digestive enzymes and bile. The mucosal phase relies on the integrity of the brush-border membrane of intestinal epithelial cells to transport digested products from the lumen into the cells. In the postabsorptive phase, reassembled lipids and other key nutrients are transported via lymphatics and portal circulation from epithelial cells to other parts of the body.

Perturbation by disease processes in any of these phases frequently results in malabsorption.

Contributor Information and Disclosures

Stephan U Goebel, MD Assistant Professor of Gastroenterology and Hepatology, Department of Medicine, Emory University School of Medicine

Stephan U Goebel, MD is a member of the following medical societies: American Gastroenterological Association, American Society for Gastrointestinal Endoscopy

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Douglas M Heuman, MD, FACP, FACG, AGAF Chief of Hepatology, Hunter Holmes McGuire Department of Veterans Affairs Medical Center; Professor, Department of Internal Medicine, Division of Gastroenterology, Virginia Commonwealth University School of Medicine

Douglas M Heuman, MD, FACP, FACG, AGAF is a member of the following medical societies: American Association for the Study of Liver Diseases, American College of Physicians, American Gastroenterological Association

Disclosure: Received grant/research funds from Novartis for other; Received grant/research funds from Bayer for other; Received grant/research funds from Otsuka for none; Received grant/research funds from Bristol Myers Squibb for other; Received none from Scynexis for none; Received grant/research funds from Salix for other; Received grant/research funds from MannKind for other.

Chief Editor

Julian Katz, MD Clinical Professor of Medicine, Drexel University College of Medicine

Julian Katz, MD is a member of the following medical societies: American College of Gastroenterology, American College of Physicians, American Gastroenterological Association, American Geriatrics Society, American Medical Association, American Society for Gastrointestinal Endoscopy, American Society of Law, Medicine & Ethics, American Trauma Society, Association of American Medical Colleges, Physicians for Social Responsibility

Disclosure: Nothing to disclose.

Additional Contributors

Tushar Patel, MB, ChB Professor of Medicine, Ohio State University Medical Center

Tushar Patel, MB, ChB is a member of the following medical societies: American Association for the Study of Liver Diseases, American Gastroenterological Association

Disclosure: Nothing to disclose.


Jan-Michael A Klapproth, MD Assistant Professor, Department of Medicine, Division of Digestive Diseases, Emory University School of Medicine

Jan-Michael A Klapproth, MD is a member of the following medical societies: American College of Gastroenterology, American Federation for Medical Research, American Gastroenterological Association, and Crohns and Colitis Foundation of America

Disclosure: Nothing to disclose.

Vincent W Yang, MD, PhD R Bruce Logue Professor, Director, Division of Digestive Diseases, Department of Medicine, Professor of Hematology and Oncology, Winship Cancer Institute, Emory University School of Medicine

Vincent W Yang, MD, PhD is a member of the following medical societies: Alpha Omega Alpha, American Gastroenterological Association, American Society for Clinical Investigation, and Association of American Physicians

Disclosure: Nothing to disclose.

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