A patient asks how long his body stores of two vitamins would last if he stopped all intake today. Which pairing of storage duration is correct?
- A Vitamin B12: several years; folate: a few months ✓
- B Vitamin B12: a few weeks; folate: several years
- C Vitamin B12: several years; folate: several years
- D Vitamin B12: a few weeks; folate: a few weeks
Correct answer: A. Vitamin B12: several years; folate: a few months
Explanation
The liver stores 3 to 5 mg of vitamin B12, enough for 3 to 5 years because of efficient enterohepatic recirculation, whereas folate stores last only about 3 to 4 months. This explains why megaloblastic anemia from dietary folate lack appears sooner than B12 deficiency in vegans, making option B the reverse of the true physiology.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.