Vitamin B12
- 40% of hospitalized elderly have low or borderline serum B12
Dietary Reference Intake (DRI)
- 2.4 mcg/day
- Because 10-30% of older people malabsorb food bound B12, it is recommended that those
>50 years meet requirements by consuming B12 fortified foods and/or a supplement containing B12. - No Tolerable Upper Intake Level (UL) has been established.
Symptoms of Deficiency
- Autonomic- urinary/fecal incontinence
- Cerebral- dementia, depression, memory loss, psychosis, CVD
- Myelopathic- abnormal gait, ataxia
- Neuropathic- paresthesia, numbness, weakness
- Hematologic- anemia, leucopenia, thrombocytopenia
Those at Risk
- > 50 years of age
- GI/Pancreatic – disease or surgery
- Rx – H2 Proton Pump inhibitors or Antagonists, antacids, Biguanides
- Institutionalized and Hospitalized elderly
Who to Screen
- Those at risk (above)
- All others, at age 50 years
- If B12 > 300 pmol/L screen q 5 years until 65 years, then annually
- If B12 < 400 pmol/L check Homocysteine
B12 Levels Indicating Therapy Required
- < 250 pmol/L
- 250 – 400 pmol/L and elevated Hcy
Recommended Repletion
- Initially 1000 mcg IM daily for 3-7 days then weekly for 4 weeks
Maintenance
- IF induced deficiency- Protein Bound Induced Deficiency
- PO 2 mg OD or PO 50 mcg OD
- IM 1000 mcg 1/12
References
- Dharmarajan TS, Norkus EP. Approaches to vitamin B12 deficiency. Early treatment may prevent devastating
complications. Postgrad Med 2001 July 110(1):99 - Snow CF. Laboratory diagnosis of vitamin B12 and folate deficiency.
- A guide for the primary care physician. Arch Intern Med 1999 June 159:1290.