Crohn's disease commonly involves which part of the GI tract, contributing to malnutrition through malabsorption?

Crohn's disease commonly involves which part of the GI tract, contributing to malnutrition through malabsorption?

• A. Stomach
• B. Esophagus
• C. Small intestine
• D. Large intestine

Answer: (C)

Absorption happens mainly in the small intestine, so inflammation from Crohn's disease here disrupts nutrient uptake and drives malnutrition. Crohn's frequently involves the terminal ileum, a key part of the small intestine, where fat and fat‑soluble vitamins are absorbed and where vitamin B12 absorption occurs. When this area is inflamed, fat malabsorption and deficiencies (including B12) lead to weight loss and nutritional problems. The stomach and esophagus are not primary sites of nutrient absorption, so disease there is less likely to cause malnutrition through malabsorption. The large intestine absorbs water and electrolytes rather than most nutrients, so involvement there tends to affect stooling more than broad malnutrition from malabsorption. Thus, the small intestine best explains why Crohn's disease leads to malnutrition via impaired absorption.

Absorption happens mainly in the small intestine, so inflammation from Crohn's disease here disrupts nutrient uptake and drives malnutrition. Crohn's frequently involves the terminal ileum, a key part of the small intestine, where fat and fat‑soluble vitamins are absorbed and where vitamin B12 absorption occurs. When this area is inflamed, fat malabsorption and deficiencies (including B12) lead to weight loss and nutritional problems.

The stomach and esophagus are not primary sites of nutrient absorption, so disease there is less likely to cause malnutrition through malabsorption. The large intestine absorbs water and electrolytes rather than most nutrients, so involvement there tends to affect stooling more than broad malnutrition from malabsorption.

Thus, the small intestine best explains why Crohn's disease leads to malnutrition via impaired absorption.