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Query: UMLS:C0024523 (malabsorption)
 7,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It is possible to point out subjects consuming considerable quantities of fructose and sorbitol, and the intake seems to be increasing both from added and natural sources. Studies of the absorption of fructose in animals are inconsistent, and the mechanisms of fructose uptake seem to vary in accordance with the species. In most species fructose absorption takes place by a specific carrier (facilitated transport), but it may be active in the rat. In vitro studies of human intestine are very scarce; there is no evidence of active intestinal fructose transport in the human intestine. By means of hydrogen breath tests, a very low absorption capacity for fructose given as the free monosaccharide has been found in humans. Fructose given as sucrose or in equimolar combinations with glucose is well absorbed, and only fructose in excess of glucose is malabsorbed. On this basis it is hypothesized that two different uptake mechanisms for fructose are present in the human intestine. One of these may be a disaccharidase-related uptake system. Sorbitol ingestion may aggravate malabsorption of fructose given as the monosaccharide; it is not known whether a specific mechanism is involved. In children and adults with functional bowel distress the absorption capacities for fructose may not differ from those of healthy individuals, but malabsorption of fructose and/or sorbitol may be the cause of or aggravate abdominal symptoms. Fructose polymers (fructans) are also subject to increasing nutritional interest. Fructans are not absorbed in the small intestine but are strongly fermented in the large bowel. Fructans may be of potential benefit for large-bowel function and blood glucose regulation.
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PMID:Fructose and related food carbohydrates. Sources, intake, absorption, and clinical implications. 143 34

Sorbitol is a hexahydroxy alcohol used as a sugar substitute in many dietetic foods and as a drug vehicle. Previous studies have suggested that sorbitol ingestion may be an additional cause of non-specific gastrointestinal distress. We evaluated sorbitol malabsorption in 30 healthy volunteers, seven patients with untreated coeliac disease and nine patients with coeliac disease on a gluten free diet, using a four hour H2 breath test. After ingestion of test solutions containing sorbitol 10 and 20 g and of four sweets (6.8 g sorbitol), 90%, 100%, and 62% of healthy volunteers, respectively had significantly raised H2 excretion, indicating malabsorption of sorbitol. Of all healthy subjects tested, 45% after 10 g, 100% after 20 g, and 50% after four sweets complained of symptoms of carbohydrate intolerance during the eight hours after sorbitol. After a 5 g dose given at concentrations of 2%, 4%, 8%, 16%, malabsorption was shown in 10%, 12%, 22%, and 43% of the healthy volunteers. Symptoms of intolerance at 5 g were experienced only at concentrations of 8% and 16%. Unlike healthy volunteers and coeliac patients on a gluten free diet, 100% of untreated coeliacs malabsorbed a 2% solution of 5 g sorbitol. These results show that malabsorption and intolerance of sorbitol may result from ingestion of doses and/or concentrations usually found in many foods and drugs; they underline the need to consider this as a possible and hitherto underestimated cause of gastrointestinal symptoms.
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PMID:Sorbitol malabsorption in normal volunteers and in patients with coeliac disease. 334 11

Patients on chronic hemodialysis have decreased food intake and decreased fat stores. Malabsorption of carbohydrates such as lactose, sorbitol, or fructose cause functional bowel symptoms. The aim of this study was to assess the role of carbohydrate malabsorption in the nutritional abnormalities of chronic hemodialysis (CHD). Eleven patients on dialysis (six Hispanic, five black Americans) were studied, compared to 11 healthy volunteers age-, race-, and sex-matched. Lactulose 10 g (transit time), lactose 12.5 g, sorbitol 5 g, and fructose 37.5 g were tested fasting. Breath [H2] was measured 4 h postprandially by gas chromatograph analysis. Positive test was defined as 20 ppm [H2] above baseline. Weight, height, and triceps skinfold were measured. One hundred percent of CHD patients were below the 50th percentile for triceps skinfold measurement and 55% were below the 10th percentile. No biochemical abnormalities were noted. Breath [H2] tests: lactulose: all patients in both groups responded with positive tests. No difference in transit time was noted. Lactose: 73% of CHD had positive test compared to 36% control. Sorbitol: 73% of CHD had positive test compared to 27% control (p less than 0.05). Fructose: 27% CHD compared to 0% control. This study confirmed that CHD patients have decreased fat stores. It demonstrates for the first time that CHD patients have increased incidence of malabsorption of sorbitol. This carbohydrate malabsorption may contribute to the nutritional abnormalities of CHD.
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PMID:Carbohydrate malabsorption in black and Hispanic dialysis patients. 374 26

Sorbitol, a polyalcohol sugar, is the sweetener in most "sugar-free" products and may produce an osmotic diarrhea if ingested in large amounts (20-50 g). Whether or not smaller amounts of ingested sorbitol may be associated with other symptoms characteristic of carbohydrate malabsorption has not been determined. Using breath hydrogen analysis, the absorption of 5, 10, and 20 g of sorbitol was studied in 7 healthy volunteers. In a majority of subjects, ingestion of as little as 5 g sorbitol was associated with a significant increase in breath hydrogen concentration. Most subjects experienced mild gastrointestinal distress (gas, bloating) after 10 g and severe symptoms (cramps, diarrhea) after 20 g. These data suggest that the evaluation of patients with "functional" gastrointestinal complaints should include careful inquiry into the use of products containing sorbitol.
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PMID:Sorbitol intolerance: an unappreciated cause of functional gastrointestinal complaints. 684 53

In the rapidly increasing elderly population, diarrhoea as a result of drug therapy is an important consideration. The elderly consume a disproportionately large number of drugs for multiple acute and chronic diseases. Drugs can compromise both immune and nonimmune responses. Aging decreases the quality and proportion of T cells which in turn reduces the production of secretory IgA, the primary immune response of the gut. Acid production in the stomach decreases with increasing age and this compromise its vital 'self-sterilising' function, thus increasing the risk of diarrhoea due to viral, bacterial and protozoal pathogens. Other nonimmune defence mechanisms include the motility of the small intestine and the host-protective commensal bacteria of the colon. Drug induced hypomotility may result in bacterial overgrowth, deconjugation of bile salts and diarrhoea. Less commonly, diarrhoea may occur due to hypermotility because of a cholinergic-like syndrome. In the colon the host-protective commensal bacteria provide a powerful defence against pathogens. Disruption of this commensal population by antibiotic therapy may result in Clostridium difficile supra-infection which causes diarrhoea through toxin production. This is especially important in the elderly patient on chemotherapy for malignancy and those with multiple diseases. The organism responds to vancomycin, metronidazole and bacitracin. Metronidazole is the suggested drug of choice, with vancomycin reserved for relapses. Drugs also cause diarrhoea by interfering with normal physiological processes. Drugs impair fluid absorption by activating adenylate cyclase within the small intestinal enterocyte which increases the level of cyclic AMP. This causes active secretion of Cl- and HCO3-, passive efflux of Na+, K+ and water and inhibition of Na+ and Cl- into the enterocyte. Examples of these drugs (secretagogues) are bisacodyl, misoprostol and chenodeoxycholic acid (used to dissolve cholesterol gallstones). Drugs may also affect a second mechanism that regulates water and electrolyte transport, the Na+, K+ exchange pump. The energy for this pump is provided by the ATPase mediated breakdown of ATP. ATPase may be inhibited by digoxin, auranofin, colchicine and olsalazine. A number of drugs cause osmotic diarrhoea including antacids containing magnesium trisilicate or hydroxide. Lactulose is being used increasingly in compensated liver disease to increase protein tolerance and prevent hepatic encephalopathy. Sorbitol, an osmotic laxative agent also used in some liquid pharmaceutical preparations, induces diarrhoea by virtue of its osmotic potential. Another mechanism by which drugs cause diarrhoea is by mucosal damage of the small and large bowel. In the small intestine mucosal damage causes diarrhoea and fat malabsorption, as may occur with neomycin and colchicine. In the colon, for example, gold salts and penicillamine cause colitis of varying severity. Though the causes of diarrhoea are diverse, a drug-associated aetiology should always be considered and actively sought and addressed to prevent the complications of dehydration, electrolyte imbalance and undernutrition.
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PMID:Mechanisms of drug-induced diarrhoea in the elderly. 978 28

Carbohydrate malabsorption is a frequent clinical condition, often associated with abdominal symptoms. Although lactose represents the most commonly malabsorbed sugar, also other carbohydrates, such as fructose, trehalose and sorbitol may be incorrectly absorbed in the small intestine. Fructose malabsorption seems more common in patients with functional bowel disease, even if randomized and controlled studies on these topic were few and on small samples. Interpretation of breath hydrogen testing is difficult. In particular, neither studies comparing this test with a gold standard, nor validated doses and concentrations to be used, are available. Trehalose malabsorption due to trehalase deficiency represents a very rare condition and available studies do not support its relevance in clinical practice. Sorbitol absorption is dose and concentration related, and depends on the entity of intestinal absorption surface. Nevertheless, the finding of its malabsorption is not expression of a specific cause of intestinal bowel damage. From available data, it is not possible to draw definite conclusions about clinical relevance of fructose, trehalose and sorbitol malabsorption, as well as, about diagnostic accuracy of commonly used tests to detect all these conditions. On the other hand, in patients who refer abdominal discomfort after ingestion of different carbohydrate-containing foods, a small intestinal bacterial overgrowth, should be promptly considered. This is because the large amount of intestinal bacteria may unspecifically ferment sugars, causing an abnormal H2 production and consequently a misleading diagnosis of sugar malabsorption.
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PMID:Fructose, trehalose and sorbitol malabsorption. 2444 64

Breath tests (BT) represent a valid and non-invasive diagnostic tool in many gastroenterological disorders. Their wide diffusion is due to the low cost, simplicity and reproducibility and their common indications include diagnosis of carbohydrate malabsorption, Helicobacter pylori infection, small bowel bacterial overgrowth, gastric emptying time and orocaecal transit time. The review deals with key points on methodology, which would influence the correct interpretation of the test and on a correct report. While a clear guideline is available for lactose and glucose breath tests, no gold standard is available for Sorbitol, Fructose or other H2 BTs. Orocaecal transit time (OCTT) defined as time between assumption of 10 g lactulose and a peak > 10 ppm over the baseline value, is a well-defined breath test. The possible value of lactulose as a diagnostic test for the diagnosis of small bowel bacterial overgrowth is still under debate. Among (13)C breath test, the best and well characterized is represented by the urea breath test. Well-defined protocols are available also for other (13)C tests, although a reimbursement for these tests is still not available. Critical points in breath testing include the patient preparation for test, type of substrate utilized, reading machines, time between when the test is performed and when the test is processed. Another crucial point involves clinical conclusions coming from each test. For example, even if lactulose could be utilized for diagnosing small bowel bacterial overgrowth, this indication should be only secondary to orocaecal transit time, and added into notes, as clinical guidelines are still uncertain.
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PMID:Tricks for interpreting and making a good report on hydrogen and 13C breath tests. 2444 74