Carbohydrate malabsorption

Abdominal pain and diarrhea with malabsorption have been described in patients taking acarbose, which can also cause carbohydrate malabsorption (39). 

Kato K, Naruse S, Kondo T, Hayakawa T. Carbohydrate malabsorption following acarbose administration. Diabet Med 1998 15(5) 393-7. 

As this patient s history indicated that his problems began soon after he started taking 2 cups of milk with lunch at school and his physical examination and stool examination findings suggested he had carbohydrate malabsorption, a diagnosis of lactose intolerance was made. It was recommended that his milk intake at lunch be decreased to half a cup (about 4 oz). His symptoms improved considerably and almost immediately. His milk intake was then gradually increased such that he was ultimately able to take up to 8 oz of milk without much complaint, especially when the milk was taken with other foods. 

Certain other patients are especially sensitive to the gastrointestinal effects of sorbitol for example, diabetics can be prone to sorbitol intolerance, because of altered gastrointestinal transit time and motility. Some of them also have a higher consumption of sorbitol-containing dietary foods. Patients on chronic hemodialysis can be predisposed to sorbitol intolerance as a result of carbohydrate malabsorption (25). 

Coyne MJ, Rodriguez H. Carbohydrate malabsorption in black and Hispanic dialysis patients. Am J Gastroenterol 1986 81(8) 662-5. 

The brush border enzymes with disaccharidase and ohgosaccharidase activity are listed in Table 48-1. The sucrase-isomaltase complex comprises most of the sucrase, isomaltase, and maltase (80%) activity of the small intestine. It hydrolyzes sucrose to its constituent monosaccharides, cleaves glucose from a-limit dextrins with 1,6 bonds, and hydrolyzes maltose. The activity of the complex is fourfold to fivefold greater in the jejunum than in the ileum. Changes in diet have a marked effect on the expression of the complex starvation leads to a rapid decline in activity, which is rapidly restored on refeeding. AH small intestinal saccha-ridases may decrease with infection or inflammation of the small bowel to the extent that carbohydrate malabsorption... 

The presence of the brush-border disaccharidases is essential for carbohydrate absorption, and a reduction in their activity leads to carbohydrate malabsorption and intolerance. Carbohydrate malabsorption does not always lead to chnical symptoms, but when symptoms do occur (e.g., abdominal pam, flatulence, and diarrhea) as a consequence of the malabsorption, the patient is described as having carbohydrate intolerance. 

Several quite different mechanisms can lead to diarrhea. In carbohydrate malabsorption, the presence of unabsorbed solutes in the bowel causes an osmotic diarrhea as water enters the bowel from the tissue. By contrast, the diarrhea of most laxative abuse and in VIPomas is due to active secretion of water and electrolytes into the bowel, which is described as secretory diarrhea. Inflammatory bowel diseases (ulcerative colitis and Crohn s disease) cause diarrhea as a consequence of the inflammatory process with loss of fluid into the bowel. 

Caspary WE. Diarrhea associated with carbohydrate malabsorption. Clin Gastroenterol 1986 15 631-55. 

Carbohydrate malabsorption can occur in a number of diseases that cause mucosal damage or dysfunction (e.g., gastroenteritis, protein deficiency, gluten-sensitive enteropathy). Disorders due to deficiencies of specific oligosaccharidases are discussed below. 

Carbohydrate malabsorption plays a major role in diarrhea associated with SBS. Unabsorbed carbohydrates are broken down by intestinal bacteria to short-chain fatty acids (SCFAs), producing an osmotic load in the distal small intestine and colon that can lead to protracted diarrhea. However, the colon is able to use these SCFAs as a source of energy, thus complex carbohydrates may provide a significant caloric source for patients with a massive resection and a preserved colon. ... 

Recently, a semisynthetic deoxynorjirimycin derivative Bay o 1248 (20), which is absorbed from the intestine and does not produce carbohydrate malabsorption, was reported as a potent glucosidase inhibitor exhibiting strong sucrase and maltase inhibitory activity and no amylase inhibition. Administration of which has a longer duration of action than acarbose, reduces food intake, body weight gain and epididymal fat pad weight in rats. ... 

Dimethyl sulfide 63 Carbohydrate malabsorption, hepatic coma, malodor... 

Carbohydrate Malabsorption 318 The Dumping Syndrome 318 Steatorrhea Idiopathic Steatorrhea Celiac Disease or Nontropical Sprue... 

Malnutrition may also result from disease of the gastrointestinal tract. Among the malabsorption syndromes, carbohydrate malabsorption due to inborn errors of metabolism, the dumping syndrome resulting from gastrectomy, and steatorrhea will be discussed [136]. 

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