Update on vitamin B12 deficiency.

Area of Science:

• Internal Medicine
• Nutritional Science
• Hematology

Background:

• Vitamin B12 (cobalamin) deficiency is a prevalent condition linked to megaloblastic anemia, neuropsychiatric symptoms, and elevated homocysteine.
• Risk factors include prolonged use of metformin and proton pump inhibitors, particularly in older populations.

Purpose of the Study:

• To review the diagnosis, screening, and management of vitamin B12 deficiency.
• To provide guidance on appropriate laboratory assessment and treatment strategies.

Main Methods:

• Review of current literature and guidelines regarding vitamin B12 deficiency.
• Analysis of diagnostic laboratory tests including complete blood count, serum vitamin B12, homocysteine, and methylmalonic acid.
• Evaluation of treatment efficacy for oral versus intramuscular vitamin B12 administration.

Main Results:

• Screening guidelines are lacking for asymptomatic, low-risk adults, but high-risk individuals may warrant testing.
• Serum vitamin B12 levels alone may be unreliable; homocysteine and methylmalonic acid aid in confirming deficiency.
• High-dose oral vitamin B12 is as effective as intramuscular administration for correcting deficiency.
• Crystalline vitamin B12 formulations are better absorbed; supplementation is advised for individuals over 50 and strict vegetarians.

Conclusions:

• Vitamin B12 deficiency requires careful diagnosis, especially in at-risk populations.
• Oral supplementation is an effective treatment option.
• Dietary sources and fortified foods are crucial for prevention in specific demographics.