The intrinsic factor essential for vitamin B12 absorption is produced by the lining of which organ?

The intrinsic factor essential for vitamin B12 absorption is produced by the lining of which organ?

• A. Stomach
• B. Small intestine
• C. Liver
• D. Pancreas

Answer: (A)

Intrinsic factor is produced by the parietal cells of the stomach’s gastric mucosa. Its role is to bind vitamin B12 so the complex can be absorbed later in the ileum. Without intrinsic factor, most dietary B12 isn’t effectively absorbed, leading to deficiency. The small intestine is where absorption happens, but it does not produce intrinsic factor; the liver and pancreas have other secretions and do not make intrinsic factor either.

Intrinsic factor is produced by the parietal cells of the stomach’s gastric mucosa. Its role is to bind vitamin B12 so the complex can be absorbed later in the ileum. Without intrinsic factor, most dietary B12 isn’t effectively absorbed, leading to deficiency. The small intestine is where absorption happens, but it does not produce intrinsic factor; the liver and pancreas have other secretions and do not make intrinsic factor either.