- Malabsorption refers to a group of conditions in which the body is unable to adequately absorb nutrients from the digestive tract into the bloodstream. These nutrients include macronutrients (proteins, fats, and carbohydrates), micronutrients (vitamins and minerals), and water.
- Malabsorption can result from problems at any stage of digestion, including enzymatic breakdown in the stomach and pancreas, bile acid-mediated fat digestion, mucosal absorption in the small intestine, or transport into the lymphatic or circulatory systems. The result is nutrient deficiencies that can lead to a wide range of clinical signs, from subtle fatigue and weight loss to severe malnutrition, developmental delays, and organ dysfunction.
- The causes of malabsorption are diverse and can be categorized broadly into digestive enzyme deficiencies, mucosal damage, bile acid disorders, and structural or functional abnormalities of the gastrointestinal tract. Common conditions include celiac disease, an autoimmune disorder triggered by gluten that damages the intestinal lining; lactose intolerance, where the body lacks the enzyme lactase to digest milk sugar; and chronic pancreatitis or cystic fibrosis, in which digestive enzymes are insufficient. Other causes include small intestinal bacterial overgrowth (SIBO), Crohn’s disease, intestinal surgeries (such as gastric bypass or bowel resection), infections (e.g., giardiasis), and radiation enteritis. Medications like antibiotics, proton pump inhibitors, and chemotherapy agents can also impair absorption.
- Symptoms of malabsorption vary depending on the nutrients involved and the underlying cause. Common general symptoms include chronic diarrhea, steatorrhea (fatty, foul-smelling stools), bloating, gas, abdominal cramps, and unintentional weight loss. Specific deficiencies lead to additional signs: iron deficiency may cause anemia and fatigue; vitamin B12 deficiency can result in neuropathy and cognitive impairment; calcium and vitamin D deficiencies can lead to bone pain and fractures; and protein deficiency may cause muscle wasting and edema. In children, prolonged malabsorption can result in growth retardation and delayed development.
- Diagnosis typically involves a combination of clinical evaluation, laboratory tests, and imaging or endoscopy. Blood tests can reveal anemia, vitamin or mineral deficiencies, and signs of inflammation. Stool studies may show fat malabsorption, parasites, or undigested food particles. Specialized tests such as the D-xylose test, hydrogen breath tests, or fecal elastase may be used to assess specific digestive functions. Endoscopic biopsy of the small intestine can help identify structural damage, such as in celiac disease or tropical sprue.
- Treatment of malabsorption focuses on addressing the underlying cause, correcting nutritional deficiencies, and supporting overall gastrointestinal function. For example, patients with celiac disease must follow a strict gluten-free diet, while those with pancreatic insufficiency may require enzyme replacement therapy. Lactose-intolerant individuals benefit from avoiding lactose or using lactase supplements. Nutritional support often includes vitamin and mineral supplementation, dietary modification, and in severe cases, parenteral (intravenous) nutrition.
