This page explains b12 absorption digestion, tracing how vitamin B12 moves from the stomach into the small intestine and why intrinsic factor matters. In the stomach, B12 is released from binding proteins by acid and enzymes, then it binds to a transport protein called haptocorrin. When the chyme enters the small intestine, pancreatic enzymes release B12 from haptocorrin, making it available to bind with intrinsic factor, a glycoprotein produced by the stomach. With IF bound, the complex travels to the ileum, where specialized receptors recognize and absorb B12. Inside intestinal cells, B12 is handed off to transcobalamin II, a transport protein, and then delivered into the bloodstream for distribution to tissues. Much of the body’s B12 is stored in the liver, and some is recycled through enterohepatic circulation, which helps maintain levels over time. Intrinsic factor matters because it is the key partner that enables B12 to cross the intestinal lining in the ileum. Any disruption in IF production, secretion, or function can alter the rate and efficiency of b12 absorption digestion, illustrating how tightly the system is coordinated across the stomach, small intestine, and liver. Quick notes on this pathway (informational): Tip 1: the journey starts in the stomach where B12 is freed and binds to intrinsic factor; Tip 2: the small intestine is where the IF-B12 complex is absorbed; Tip 3: after absorption, B12 is carried in the blood by transcobalamin II; Tip 4: enterohepatic circulation helps reuse B12; Tip 5: the whole process is a coordinated sequence from stomach through ileum to circulation. These notes describe the b12 absorption digestion process for educational purposes and are not medical recommendations.
