Short note on vitamin B12 deficiency

While browsing the almost endless holy grail of knowledge on everything musculoskeletal I’ve stumbled on a mention of B12 deficit and misconceptions related to that. I’ve read the following article and must say I was surprised. So here’s what I’ve learned:

- serum level of B12 is not a good guide for either the diagnosis of deficiency or the success or lack thereof of treatment
- neurological and psychiatric symptoms can develop before any sign of anemia
- test for antibodies to intrinsic factor is negative in 30–50% of patients with pernicious anemia
- after vitamin B12 injection its level in blood is understandably increases so that checking it later is useless
- 60 years of use and research has not yielded a single case of an overdose, contrary to a common belief

Bottom line:
- instead of using serum B12 levels alone, it is better to supplement it with test for the level of methylmalonic acid (MMA) or better still use the symptoms as a guideline for both diagnosing deficiency and treating it, including the dose titration.