You are lucky.....you must still have some intrinsic factor activity.
This however can be blocked in many people who use acid blocking drugs for heartburn, or who have poor acid levels in the stomach due to genetic errors in intrinsic factor activity, or who are older. The presence of food in GI tract (small intestine) tends to absorb microgram amounts of certain drugs like digoxin and thyroid hormones. Studies have found poor absorption of microgram type doses.

There is a study done by a doctor measuring absorption under ideal conditions...of B12 and it is very small. About 13mcg for a dose of 1000mcg, on an empty stomach.
So unless everyone gets B12 tests periodically, they will never know if they are absorbing properly unless they take it on an empty stomach.

Here is the paper...
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2532799/

and the link to his table with doses:
http://www.ncbi.nlm.nih.gov/pmc/arti...able/T1/#TF1-4

In the younger age groups who post here, it is less common
to have low B12 unless the person has a terrible diet or is anorectic, or has the genes for pernicious anemia.

But for many of the posters on NeuroTalk, the empty stomach is
important.

Also another point... about 10-30% of the population has been found to be unable to methylate B12 and folic acid. This failure means that cyanocobalamin form will not work for them.
They require methylfolate and methylcobalamin for supplementation therefore. The 23andme website has now lowered its price again for DNA testing for this genetic error, and it is now $99. (for those interested.)

Those with Celiac and/or gluten intolerance, and those with inflammatory bowel diseases, malabsorption of B12 does occur.
So B12 is not a simple thing to supplement when all these factors may be present.