Which of the following is a risk factor for megaloblastic anemia?

• A. Achlorhydria
• B. Hypertension
• C. Hyperlipidemia
• D. Ileal resection

Answer: (D)

Megaloblastic anemia happens when DNA synthesis in red blood cell precursors is impaired due to a deficiency of vitamin B12 or folate. For vitamin B12, absorption hinges on intrinsic factor in the stomach and uptake in the terminal ileum. If the ileum is removed or severely damaged, the B12–intrinsic factor complex can’t be absorbed, leading to B12 deficiency and the characteristic megaloblastic changes.

Among the options, removing or bypassing the ileum directly disrupts B12 absorption, making it a clear risk factor. The other choices don’t have a direct, strong link: lack of stomach acid (achlorhydria) can affect B12 release from food but is not as decisive as ileal loss; hypertension and hyperlipidemia are unrelated to the development of megaloblastic anemia.