B12 levels

My b12 level is 220.  Normal is noted on the report as 180-900.  My internist suggest 2000 mcg of b12 per day to increase my b12 levels.  He says that he went to a continuing education course that said that it was best to keep levels over 330.  He could not cite a specific study and I couldn't find anything to that effect by googling.   I'd rather not treat a normal result unless there is some real reason to do it, especially with b12 supplements 32,000 times the RDA.

Any thoughts about this, or does anyone know what study he may have been referencing?

[KathleenMarie]

How do you feel day by day?  Any tiredness, dizziness or just run down feelings over time? -- might be an indicator of a need to take a supplement.  My levels went up after taking some of the supplemented beverages and Spirulina products, not so intensive, also delicious.  I only did a liquid vitamen supplement periodically over a years' time.  Getting back to 331 on B12 did seem to make a difference in energy and feeling well.   Now it's right over 330.  Best, KathleenM