Which vitamin deficiency is most commonly associated with Roux-en-Y gastric bypass?

Which vitamin deficiency is most commonly associated with Roux-en-Y gastric bypass?

• A. Vitamin B12
• B. Vitamin D
• C. Vitamin C
• D. Vitamin B1

Answer: (D)

Roux-en-Y gastric bypass alters the stomach and proximal gut, reducing acid and intrinsic factor production, which are essential for vitamin B12 absorption. Vitamin B12 needs intrinsic factor from the stomach to be absorbed in the terminal ileum, and bypassing large parts of the stomach makes this process less efficient over time. Because B12 stores in the body can last years, deficiency tends to appear chronically after the procedure and is, overall, the most commonly seen nutritional shortfall. That deficiency presents with fatigue and macrocytic anemia, and can involve neurologic symptoms like neuropathy or confusion if not addressed. Treatment is lifelong B12 supplementation, often via injections or high-dose oral therapy, to bypass reliance on intrinsic factor. While deficiencies in fat-soluble vitamins (like D) or thiamine can occur, they are not as common as B12 after this surgery.

Roux-en-Y gastric bypass alters the stomach and proximal gut, reducing acid and intrinsic factor production, which are essential for vitamin B12 absorption. Vitamin B12 needs intrinsic factor from the stomach to be absorbed in the terminal ileum, and bypassing large parts of the stomach makes this process less efficient over time. Because B12 stores in the body can last years, deficiency tends to appear chronically after the procedure and is, overall, the most commonly seen nutritional shortfall. That deficiency presents with fatigue and macrocytic anemia, and can involve neurologic symptoms like neuropathy or confusion if not addressed. Treatment is lifelong B12 supplementation, often via injections or high-dose oral therapy, to bypass reliance on intrinsic factor. While deficiencies in fat-soluble vitamins (like D) or thiamine can occur, they are not as common as B12 after this surgery.