section_path: Non-destructive digestion
section_name: Non-destructive digestion
paragraph_text: Non-destructive digestion
  
  Some nutrients are complex molecules (for example vitamin B) which would be destroyed if they were broken down into their functional groups. To digest vitamin B non-destructively, haptocorrin in saliva strongly binds and protects the B molecules from stomach acid as they enter the stomach and are cleaved from their protein complexes.
  
  After the B -haptocorrin complexes pass from the stomach via the pylorus to the duodenum, pancreatic proteases cleave haptocorrin from the B molecules which rebind to intrinsic factor (IF). These B -IF complexes travel to the ileum portion of the small intestine where cubilin receptors enable assimilation and circulation of B -IF complexes in the blood.