In cystic fibrosis, fat malabsorption commonly leads to fat-soluble vitamin deficiencies. Which organ dysfunction primarily causes this malabsorption?

• A. Bile salt deficiency
• B. Small intestinal mucosal disease
• C. Exocrine pancreatic insufficiency
• D. Dietary fat deficiency

Answer: (C)

Fat digestion relies on pancreatic enzymes, especially lipase, working in the small intestine, with bile salts helping emulsify fats for micelle formation. In cystic fibrosis, blocked pancreatic ducts lead to exocrine pancreatic insufficiency, so enzymes like lipase aren’t adequately released into the gut. Without sufficient lipase, triglycerides aren’t digested into absorbable components, micelles don’t form effectively, and fat—and thus fat-soluble vitamins A, D, E, and K—are poorly absorbed. This pancreatic enzyme deficiency is the primary driver of fat malabsorption in CF. While bile salt deficiency or intestinal mucosal disease can cause malabsorption, they’re not the main issue in this scenario, and dietary fat deficiency wouldn’t by itself cause these fat-soluble vitamin losses.