This review explains how carbohydrate maldigestion and malabsorption can contribute to abdominal pain, bloating, flatulence, cramping, diarrhea, and altered bowel habits. Carbohydrate digestion occurs through luminal breakdown, largely involving pancreatic amylase, and mucosal digestion by brush-border enzymes that reduce carbohydrates to absorbable monosaccharides. When carbohydrates are incompletely absorbed, they reach the colon, where bacterial fermentation produces short-chain fatty acids and gases such as hydrogen, methane, and carbon dioxide. These byproducts can increase motility, secretion, bloating, distension, and other gastrointestinal symptoms.

The review emphasizes that carbohydrate intolerance, malabsorption, and enzyme deficiency are often confused but are not interchangeable. Primary causes include rare congenital enzyme or transporter defects, while secondary causes include pancreatic insufficiency, mucosal disease, intestinal resection, small intestinal bacterial overgrowth, radiation injury, and medication-related injury. Diagnosis can be difficult because symptoms overlap with irritable bowel syndrome and patient-reported food triggers are not always reliable. Hydrogen and methane breath testing may help, but results require careful interpretation because false positives and false negatives can occur. The authors conclude that diagnosis should combine symptom patterns, breath testing when appropriate, response to dietary exclusion, and, in select cases, enzyme assay or genetic testing.

Reference: Omer A, Quigley EMM. Carbohydrate maldigestion and malabsorption. Clin Gastroenterol Hepatol. 2018 Aug;16(8):1197-1199. doi: 10.1016/j.cgh.2018.01.048. PMID: 29425782.

This international survey examined how pancreatologists diagnose and manage exocrine pancreatic insufficiency (EPI) in patients with chronic pancreatitis (CP). Among 252 respondents, most used fecal elastase-1 as the first-choice diagnostic test, but there was no consensus on the best cutoff value or on when and how often patients should be screened. Many clinicians screened for EPI at the time of CP diagnosis or when symptoms appeared, but fewer supported annual screening. Most agreed that diagnosis should consider clinical symptoms, pancreatic function testing, and nutritional markers together. However, practice varied widely, especially in patients with subclinical EPI or nutritional deficiencies without classic steatorrhea.

Treatment practices also varied. Pancreatic enzyme replacement therapy (PERT) was commonly prescribed for clinically evident steatorrhea or a positive pancreatic function test with symptoms, weight loss, or laboratory signs of malnutrition. However, approaches differed on when to start PERT, how to dose it, how to assess response, and what to do when symptoms persisted. Most clinicians used symptom improvement and nutritional status to judge efficacy. Unsatisfactory response often led to increased enzyme dosing, addition of a proton pump inhibitor, dietician referral, or evaluation for other causes of maldigestion. The authors conclude that EPI in CP remains underdiagnosed and undertreated, despite available guidelines, and that clearer international guidance and stronger evidence are needed to standardize care.

Reference: de Rijk FEM, van Veldhuisen CL, Besselink MG, et al. Diagnosis and treatment of exocrine pancreatic insufficiency in chronic pancreatitis: an international expert survey and case vignette study. Pancreatology. 2022 May;22(4):457-465. doi: 10.1016/j.pan.2022.03.013.

This review evaluated evidence for pancreatic enzyme replacement therapy (PERT) in patients with exocrine pancreatic insufficiency (EPI) due to cystic fibrosis, chronic pancreatitis, pancreatic cancer, or pancreatic surgery. Across clinical studies, PERT consistently improved fat and protein absorption and reduced EPI-related gastrointestinal symptoms such as steatorrhea, abdominal pain, bloating, flatulence, and stool frequency. In cystic fibrosis, PERT was associated with better nutrient absorption and age-appropriate growth or weight gain in children. In chronic pancreatitis, trials showed improvements in absorption, body weight, BMI, stool symptoms, and some quality-of-life measures.

The review also discusses the potential relationship between PERT, nutritional status, quality of life, and survival, especially in pancreatic cancer and post-surgical patients. While long-term survival data are limited and sometimes inconsistent, several retrospective studies suggest that PERT may be associated with improved survival in pancreatic cancer, particularly when EPI-related weight loss and malnutrition are addressed. Despite this, PERT appears underused or underdosed in real-world practice, even among patients with malabsorption symptoms. The authors conclude that PERT is effective for EPI-related malabsorption and symptom control, but more long-term studies are needed to clarify its impact on survival.

Reference: Layer P, Kashirskaya N, Gubergrits N. Contribution of pancreatic enzyme replacement therapy to survival and quality of life in patients with pancreatic exocrine insufficiency. World J Gastroenterol. 2019 May 28;25(20):2430-2441. doi: 10.3748/wjg.v25.i20.2430. PMID: 31171887; PMCID: PMC6543241.