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American Journal of Physiology.... Feb 2011Fructose is a hexose sugar that is being increasingly consumed in its monosaccharide form. Patients who exhibit fructose malabsorption can present with gastrointestinal... (Review)
Review
Fructose is a hexose sugar that is being increasingly consumed in its monosaccharide form. Patients who exhibit fructose malabsorption can present with gastrointestinal symptoms that include chronic diarrhea and abdominal pain. However, with no clearly established gastrointestinal mechanism for fructose malabsorption, patient analysis by the proxy of a breath hydrogen test (BHT) is controversial. The major transporter for fructose in intestinal epithelial cells is thought to be the facilitative transporter GLUT5. Consistent with a facilitative transport system, we show here by analysis of past studies on healthy adults that there is a significant relationship between fructose malabsorption and fructose dose (r = 0.86, P < 0.001). Thus there is a dose-dependent and limited absorption capacity even in healthy individuals. Changes in fructose malabsorption with age have been observed in human infants, and this may parallel the developmental regulation of GLUT5 expression. Moreover, a GLUT5 knockout mouse has displayed the hallmarks associated with profound fructose malabsorption. Fructose malabsorption appears to be partially modulated by the amount of glucose ingested. Although solvent drag and passive diffusion have been proposed to explain the effect of glucose on fructose malabsorption, this could possibly be a result of the facilitative transporter GLUT2. GLUT5 and GLUT2 mRNA have been shown to be rapidly upregulated by the presence of fructose and GLUT2 mRNA is also upregulated by glucose, but in humans the distribution and role of GLUT2 in the brush border membrane are yet to be definitively decided. Understanding the relative roles of these transporters in humans will be crucial for establishing a mechanistic basis for fructose malabsorption in gastrointestinal patients.
Topics: Absorption; Aging; Animals; Biological Transport; Breath Tests; Exhalation; Fructose; Glucose; Glucose Transporter Type 2; Glucose Transporter Type 5; Humans; Hydrogen; Intestinal Mucosa; Malabsorption Syndromes; Mutation
PubMed: 21148401
DOI: 10.1152/ajpgi.00457.2010 -
Frontiers in Endocrinology 2021Levothyroxine (L-T4) absorption can be impaired by various causes: a) L-T4 ingestion during breakfast, or with food; b) conditions of reduced gastric acidity; c)... (Review)
Review
Levothyroxine (L-T4) absorption can be impaired by various causes: a) L-T4 ingestion during breakfast, or with food; b) conditions of reduced gastric acidity; c) intestinal procedures and diseases such as bariatric surgery, lactose intolerance (LI), celiac disease (CD), inflammatory bowel disease; d) drugs that alter L-T4 absorption, increasing the gastric pH, or preventing the dissolution of tablets. The development of new oral formulations, i.e. the liquid preparation and the soft gel capsule, represents the most recent advance regarding L-T4 therapy. Treating hypothyroidism with L-T4 tablets can lead to an improper control of thyroid-stimulating hormone (TSH) in ~10%-15% of patients. The improperly elevated TSH is usually managed by increasing the L-T4 daily dose, and revaluating TSH upon 2-6 months. The increase of the L-T4 dosage may cause iatrogenic hyperthyroidism, especially when the underlying disorders are cured. Liquid L-T4 can be administered in patients unable to swallow capsules or tablets, and this is one of its major benefits. Liquid L-T4 can: 1- overcome food and beverages interference; 2- bypass the malabsorption associated with an increased gastric pH; 3- circumvent the issue of malabsorption in patients who underwent bariatric surgery; 4-maintain TSH values under control better than L-T4 tablets in hypothyroid patients with typical or atypical CD, or in patients with LI. Few clinical studies evaluated soft gel L-T4 with encouraging findings in patients with gastric- or coffee-related malabsorption, or hypothyroid patients without malabsorption. Additional research is necessary to investigate liquid L-T4, or soft gel capsule, in other conditions of altered L-T4 absorption.
Topics: Administration, Oral; Hormone Replacement Therapy; Humans; Malabsorption Syndromes; Thyroxine
PubMed: 33708175
DOI: 10.3389/fendo.2021.626371 -
American Family Physician Nov 2011Chronic diarrhea, defined as a decrease in stool consistency for more than four weeks, is a common but challenging clinical scenario. It can be divided into three basic... (Review)
Review
Chronic diarrhea, defined as a decrease in stool consistency for more than four weeks, is a common but challenging clinical scenario. It can be divided into three basic categories: watery, fatty (malabsorption), and inflammatory. Watery diarrhea may be subdivided into osmotic, secretory, and functional types. Watery diarrhea includes irritable bowel syndrome, which is the most common cause of functional diarrhea. Another example of watery diarrhea is microscopic colitis, which is a secretory diarrhea affecting older persons. Laxative-induced diarrhea is often osmotic. Malabsorptive diarrhea is characterized by excess gas, steatorrhea, or weight loss; giardiasis is a classic infectious example. Celiac disease (gluten-sensitive enteropathy) is also malabsorptive, and typically results in weight loss and iron deficiency anemia. Inflammatory diarrhea, such as ulcerative colitis or Crohn disease, is characterized by blood and pus in the stool and an elevated fecal calprotectin level. Invasive bacteria and parasites also produce inflammation. Infections caused by Clostridium difficile subsequent to antibiotic use have become increasingly common and virulent. Not all chronic diarrhea is strictly watery, malabsorptive, or inflammatory, because some categories overlap. Still, the most practical diagnostic approach is to attempt to categorize the diarrhea by type before testing and treating. This narrows the list of diagnostic possibilities and reduces unnecessary testing. Empiric therapy is justified when a specific diagnosis is strongly suspected and follow-up is available.
Topics: Chronic Disease; Clostridium Infections; Diagnosis, Differential; Diarrhea; Humans; Inflammatory Bowel Diseases; Intestinal Diseases; Malabsorption Syndromes; Medical History Taking; Physical Examination
PubMed: 22085666
DOI: No ID Found -
The Pan African Medical Journal 2018
Topics: Dehydration; Diarrhea; Humans; Hypernatremia; Infant, Newborn; Infant, Premature; Malabsorption Syndromes; Male; Microvilli; Mucolipidoses
PubMed: 30364420
DOI: 10.11604/pamj.2018.30.109.12330 -
Deutsches Arzteblatt International Nov 2013Adverse food reactions (AFR) have has recently attracted increased attention from the media and are now more commonly reported by patients. Its classification,... (Review)
Review
BACKGROUND
Adverse food reactions (AFR) have has recently attracted increased attention from the media and are now more commonly reported by patients. Its classification, diagnostic evaluation, and treatment are complex and present a considerable challenge in clinical practice. Non-immune-mediated types of food intolerance have a cumulative prevalence of 30% to 40%, while true (immune-mediated) food allergies affect only 2% to 5% of the German population.
METHOD
We selectively searched the literature for pertinent publications on carbohydrate malabsorption, with special attention to published guidelines and position papers.
RESULTS
Carbohydrate intolerance can be the result of a rare, systemic metabolic defect (e.g., fructose intolerance, with a prevalence of 1 in 25,000 persons) or of gastrointestinal carbohydrate malabsorption. The malabsorption of simple carbohydrates is the most common type of non-immune-mediated food intolerance, affecting 20% to 30% of the European population. This condition is caused either by deficient digestion of lactose or by malabsorption of fructose and/or sorbitol. Half of all cases of gastrointestinal carbohydrate intolerance have nonspecific manifestations, with a differential diagnosis including irritable bowel syndrome, intolerance reactions, chronic infections, bacterial overgrowth, drug side effects, and other diseases. The diagnostic evaluation includes a nutritional history, an H2 breath test, ultrasonography, endoscopy, and stool culture.
CONCLUSION
The goals of treatment for carbohydrate malabsorption are to eliminate the intake of the responsible carbohydrate substance or reduce it to a tolerable amount and to assure the physiological nutritional composition of the patient's diet. In parallel with these goals, the patient should receive extensive information about the condition, and any underlying disease should be adequately treated.
Topics: Breath Tests; Carbohydrate Metabolism, Inborn Errors; Diagnosis, Differential; Dietary Carbohydrates; Endoscopy, Gastrointestinal; Feces; Humans; Malabsorption Syndromes; Medical History Taking; Ultrasonography
PubMed: 24300825
DOI: 10.3238/arztebl.2013.0775 -
Current Opinion in Gastroenterology Mar 2020Disaccharidase testing, as applied to the evaluation of gastrointestinal disturbances is available but it is not routinely considered in the diagnostic work-up. The... (Review)
Review
PURPOSE OF REVIEW
Disaccharidase testing, as applied to the evaluation of gastrointestinal disturbances is available but it is not routinely considered in the diagnostic work-up. The purpose of this review was to determine if disaccharidase testing is clinically useful and to consider how the results could alter patient management.
RECENT FINDINGS
Indicate that carbohydrate maldigestion could contribute functional bowel disorders and negatively impact the fecal microbiome. Diagnostic techniques include enzyme activity assays performed on random endoscopically obtained small intestinal biopsies, immunohistochemistry, stable isotope tracer and nonenriched substrate load breath testing, and genetic testing for mutations. More than 40 sucrase--isomaltase gene variants coding for defective or reduced enzymatic activity have been reported and deficiency conditions are more common than previously thought.
SUMMARY
The rationale for disaccharidase activity testing relates to a need to fully assess unexplained recurrent abdominal discomfort and associated symptoms. All disaccharidases share the same basic mechanism of mucosal expression and deficiency has far reaching consequences. Testing for disaccharidase expression appears to have an important role in symptom evaluation, but there are accuracy and logistical issues that should be considered. It is likely that specific recommendations for patient management, dietary modification, and enzyme supplementation would come from better testing methods.
Topics: Disaccharidases; Fermentation; Gastrointestinal Diseases; Gastrointestinal Microbiome; Humans; Malabsorption Syndromes
PubMed: 31990709
DOI: 10.1097/MOG.0000000000000614 -
World Journal of Gastroenterology Oct 2009Anemia is a frequent finding in most diseases which cause malabsorption. The most frequent etiology is the combination of iron and vitamin B12 deficiency. Celiac disease... (Review)
Review
Anemia is a frequent finding in most diseases which cause malabsorption. The most frequent etiology is the combination of iron and vitamin B12 deficiency. Celiac disease is frequently diagnosed in patients referred for evaluation of iron deficiency anemia (IDA), being reported in 1.8%-14.6% of patients. Therefore, duodenal biopsies should be taken during endoscopy if no obvious cause of iron deficiency (ID) can be found. Cobalamin deficiency occurs frequently among elderly patients, but it is often unrecognized because the clinical manifestations are subtle; it is caused primarily by food-cobalamin malabsorption and pernicious anemia. The classic treatment of cobalamin deficiency has been parenteral administration of the vitamin. Recent data suggest that alternative routes of cobalamin administration (oral and nasal) may be useful in some cases. Anemia is a frequent complication of gastrectomy, and has been often described after bariatric surgery. It has been shown that banding procedures which maintain digestive continuity with the antrum and duodenum are associated with low rates of ID. Helicobacter pylori (H. pylori) infection may be considered as a risk factor for IDA, mainly in groups with high demands for iron, such as some children and adolescents. Further controlled trials are needed before making solid recommendations about H. pylori eradication in these cases.
Topics: Anemia; Anemia, Iron-Deficiency; Celiac Disease; Gastrectomy; Helicobacter Infections; Humans; Iron Deficiencies; Malabsorption Syndromes; Parenteral Nutrition; Vitamin B 12; Vitamin B 12 Deficiency
PubMed: 19787827
DOI: 10.3748/wjg.15.4644 -
Nutrients Mar 2021Carbohydrate malabsorption is a frequent digestive problem associated with abdominal pain, bloating and diarrhea. Hydrogen breath testing (BT) represents the most... (Review)
Review
BACKGROUND
Carbohydrate malabsorption is a frequent digestive problem associated with abdominal pain, bloating and diarrhea. Hydrogen breath testing (BT) represents the most reliable and validated diagnostic technique. The aim of this manuscript was to clarify the usefulness of BTs in the nutritional management of these disorders.
METHODS
A literature search for BT related to carbohydrate malabsorption was carried out using the online databases of Pubmed, Medline and Cochrane.
RESULTS
Lactose BT showed good sensitivity and optimal specificity for lactose malabsorption. However, an accurate diagnosis of lactose intolerance should require blind lactose challenge although this method is difficult to utilize in clinical practice. Regarding dose-depending fructose and sorbitol malabsorption, BTs could not add diagnostic advantage compared with a direct dietary intervention. In addition, carbohydrates are fundamental components of fermentable oligo-, di- and monosaccharides and polyols (FODMAPs). Before starting a low FODMAP diet, lactose BT should be suggested in a population with low prevalence of hypolactasia.
CONCLUSIONS
BTs represent a valid and noninvasive technique in many digestive conditions. Regarding the management of carbohydrate intolerance, lactose BT can be recommended with some limitations. No sufficient evidence is available about the usefulness of BTs for other sugars in clinical practice.
Topics: Breath Tests; Carbohydrate Metabolism; Humans; Hydrogen; Malabsorption Syndromes
PubMed: 33802839
DOI: 10.3390/nu13030974 -
BMC Gastroenterology Apr 2024Food malabsorption and intolerance is implicated in gastrointestinal symptoms among patients with irritable bowel syndrome (IBS). Key triggers include fructose and...
BACKGROUND
Food malabsorption and intolerance is implicated in gastrointestinal symptoms among patients with irritable bowel syndrome (IBS). Key triggers include fructose and fructan. Prior studies examined fructose and fructan malabsorption separately in IBS patients. None have concurrently assessed both within the same patient group. We aimed to investigate the association between fructose and fructan malabsorption in the same patients with IBS using hydrogen breath testing (HBT).
METHODS
We retrospectively identified patients with IBS who underwent fructose and fructan HBTs and abstracted their results from the electronic medical record. Fructose and fructan HBTs were performed by administering a 25 g fructose solution or 10 g fructan solution, followed by breath hydrogen readings every 30 min for 3 h. Patients were positive for fructose or fructan malabsorption if breath hydrogen levels exceeded 20 ppm.
RESULTS
Of 186 IBS patients, 71 (38.2%) were positive for fructose malabsorption and 91 (48.9%) were positive for fructan malabsorption. Of these patients, 42 (22.6%) were positive for fructose malabsorption and fructan malabsorption. Positive fructose HBT readings were significantly associated with positive fructan HBT readings (p = 0.0283). Patients positive for fructose malabsorption or fructan malabsorption had 1.951 times higher odds of testing positive for the other carbohydrate.
CONCLUSIONS
Our results reveal a clinically significant association between fructose malabsorption and fructan malabsorption in patients with IBS. Fructan malabsorption should be assessed in patients with fructose malabsorption, and vice versa. Further studies are required to identify the mechanisms underlying our findings.
Topics: Humans; Irritable Bowel Syndrome; Fructose; Female; Breath Tests; Male; Retrospective Studies; Malabsorption Syndromes; Fructans; Adult; Middle Aged; Hydrogen
PubMed: 38654193
DOI: 10.1186/s12876-024-03230-x -
Frontiers in Endocrinology 2020Oral levothyroxine sodium is absorbed in the small intestine, mainly in the jejunum and the ileum being lower the absorption rate at duodenal level. The time interval... (Review)
Review
Oral levothyroxine sodium is absorbed in the small intestine, mainly in the jejunum and the ileum being lower the absorption rate at duodenal level. The time interval between the ingestion of oral thyroxine and its appearance in the plasma renders unlike a gastric absorption of the hormone. However, several evidence confirm the key role of the stomach as a prerequisite for an efficient absorption of oral levothyroxine. In the stomach, in fact, occur key steps leading to the dissolution of thyroxine from the solid form, the process bringing the active ingredient from the pharmaceutical preparation to the aqueous solution. In particular, gastric juice pH, volume, viscosity, as well as gastric emptying time seem to be the most important limiting factors. These hypotheses are confirmed by the detection of an increased need for levothyroxine in patients with infection, chronic atrophic gastritis, gastroparesis, or in simultaneous treatment with drugs interfering with gastric acidic output. The aim of the present article is to focus on the knowledge of pathophysiologic events that determine the absorptive fate of traditional (tablet) and alternative thyroxine preparations (softgel capsule and liquid solution) in patients bearing gastric disorders.
Topics: Administration, Oral; Animals; Gastric Absorption; Gastric Emptying; Gastroparesis; Helicobacter Infections; Humans; Malabsorption Syndromes; Thyroxine
PubMed: 33584549
DOI: 10.3389/fendo.2020.621616