Vitamin B12 doses and the elderly

I want to comment further on the vitamin B12 (VB12) doses discussed in Kolber and Houle’s article in the February issue of Canadian Family Physician.¹ I have treated most of my elderly patients with VB12 deficiency with oral VB12 for years. Many patients who use 1000 μg of VB12 daily end up with high or out-of-range VB12 levels within months. Most people need only 250 to 500 μg of VB12 daily to achieve normal VB12 levels.

Studies have shown that VB12 and folate supplementation might not be innocuous and might increase total mortality (20%) and cancer mortality (38%) when used to prevent cardiovascular disease.² Therefore, I believe that people can safely start taking 500 μg of VB12 daily, and that VB12 levels should be checked at 4 weeks to see if levels are normal and checked annually thereafter.

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