"Intrinsic factor" is essential to absorb b12... there are some supplements that include "intrinsic factor" out there.
"Historically, vitamin B12 was discovered from its relationship to the disease pernicious anemia, which is an autoimmune disease that destroys parietal cells in the stomach that secrete intrinsic factor. Intrinsic factor is crucial for the normal absorption of B12, therefore, a lack of intrinsic factor, as seen in pernicious anemia, causes a vitamin B12 deficiency"
"Therefore, absorption of food vitamin B12 requires an intact and functioning stomach, exocrine pancreas, intrinsic factor, and small bowel. Problems with any one of these organs makes a vitamin B12 deficiency possible"
"Individuals who lack intrinsic factor have a decreased ability to absorb B12. This results in 80-100% excretion of oral doses in the feces versus 30-60% excretion in feces as seen in individuals with adequate intrinsic factor."