Vitamins & Nutritional Supplements for Vitamin B12 Deficiency

Normally, only 3 to 4 mcg per day of vitamin B12 is required to prevent dietary deficiency. If gastrointestinal function is normal, even these small amounts of vitamin B12 from oral supplementation can prevent deficiency in vegans. If a deficiency already exists, most doctors will recommend an initial vitamin B12 injection, then oral amounts ranging from 500 mcg to 1,000 mcg per day until symptoms subside; this is followed by a maintenance level of approximately 10 mcg per day to prevent future deficiencies.

In a person with true PA, initial B12 supplementation should begin with an injection given by a qualified healthcare professional. After blood abnormalities are reversed, maintenance supplementation can be successfully accomplished with oral vitamin B12 at 1,000 to 2,000 mcg (1 to 2 mg) per day and does not require further injections. In a person lacking intrinsic factor, only about 1% of this oral amount (10–20 mcg) will be absorbed, but that amount is more than sufficient to prevent future vitamin B12 deficiency. Many physicians are unaware of this well-researched option and thus unnecessarily recommend lifelong B12 injections...

Caution: Individuals with vitamin B12 deficiency must not take largeamounts (greater than 800 mcg per day) of folicacid without the supervision of a doctor. At high levels, folic acid can mask the signs ofvitamin B12 deficiency, potentially resulting in serious and irreversible nerve damage.