Mehlman High Yield Risk Factors Practice Test

Macrocytic (megaloblastic) anemia with hypersegmented neutrophils arises when DNA synthesis in developing blood cells is impaired, most commonly from deficiencies of vitamin B12 or folate. In a vegan, vitamin B12 is the most likely missing nutrient because B12 is found almost exclusively in animal-derived foods and not in plant sources unless fortified. Folate, while it can cause a similar blood picture, is abundant in many vegan-friendly foods like leafy greens and legumes, making folate deficiency less likely in this dietary context. Iron deficiency would present as microcytic anemia, not macrocytic. Therefore, the deficiency most consistent with this patient’s vegan diet is vitamin B12 deficiency due to veganism.