Paul Wischmeyer/LinkedIn
Feb 17, 2026, 15:42
Paul Wischmeyer: Nutrient Absorption in the GI Tract
Paul Wischmeyer, Professor of Anesthesiology and Surgery with Tenure at Duke University School of Medicine, shared a post on LinkedIn:
“Nutrient Absorption in the GI Tract
How and Where Nutrients Are Absorbed
Duodenum (mixing plus minerals)
- Acid plus bile plus pancreatic enzymes meet here
- Iron uptake is primarily proximal (risk: low iron if proximal disease/bypass)
- Calcium/Mg begin early; vitamin D status matters
- Folate tends to be more proximal
Jejunum (macronutrient workhorse)
- Carbs: brush-border digestion → glucose/galactose/fructose absorption
- Protein: amino acids + small peptides via high-capacity transport
- Fat: micelles deliver lipids for absorption (needs bile + enzymes)
- Many water-soluble vitamins are absorbed across the small bowel
Ileum (specialists)
- B12 requires intrinsic factor + terminal ileum receptors
- Bile acid recycling preserves the bile pool → supports fat + A/D/E/K absorption
Colon (salvage + microbiome)
- Reclaims water, Na⁺, Cl⁻
- Fiber → microbiome → SCFAs (e.g., butyrate) that fuel colon cells and support barrier function
- Some vitamin K/biotin from microbial activity
- Why this infographic matters in real life:
If someone has:
- Crohn’s in the terminal ileum to think B12 deficiency + bile acids
- Celiac (proximal small bowel) to think iron, folate, calcium deficiency
- Pancreatic insufficiency / cholestasis to think fat plus fat-soluble vitamins (A/D/E/K) deficiency
- Short bowel or bariatric bypass to think site-specific + global malabsorption risk
Understanding the map helps you understand the labs, symptoms, and fixes.”

Stay updated with Hemostasis Today.
-
May 18, 2026, 14:47Ting Yuan: Understanding the Complexity Behind Repeated IVF Failure
-
May 18, 2026, 14:33Global Resolution on Advancing Comprehensive Care and Health Equity for People with Bleeding Disorders Worldwide at the 79th WHA – WFH
-
May 18, 2026, 14:25Salih Ehsan: Key Diagnostic Clues in Thalassemia Minor
-
May 18, 2026, 14:02Matteo Foschi: A Global Gathering for Stroke Innovation and Research at ESOC 2026
-
May 18, 2026, 14:01Who is the NBA? – Haemophilia Foundation Australia
-
May 18, 2026, 14:00Julie Makani: Partnership between Tanzania and the USA – Health Sciences
-
May 18, 2026, 13:58Alejandro González Veliz: Cardiology Enters the Era of Inflammation
-
May 18, 2026, 13:50Arshad-Ali Auhammad: Celebrating Youth Leadership in the Global Bleeding Disorders Community
-
May 18, 2026, 13:36Zain Khalpey: In Cardiovascular Medicine Flow Is Everything