Vitamin B12 functions as an essential coenzyme in humans. The absorption of this molecule and its subsequent distribution in the body is mediated by a complex set of carrier proteins, receptors and transporters. This Review describes basic and clinical features of this multistep pathway with emphasis on the gastrointestinal transport of vitamin B12and its importance in clinical medicine.
- Marianne J. Nielsen
- Mie R. Rasmussen
- Søren K. Moestrup