Intrinsic Factor is another name you hear all the time in conjunction with vitamin B12 deficiency anemia and pernicious anemia. It is a glycoprotein that is produced by cells in your stomach. The intrinsic factor is vital in B12 distribution through your body.
It is a little confusing when you try to figure out what the intrinsic factor is. Like I’ve said before I am not a doctor, just a person with this condition. I found all the medical jargon to be extremely frustrating so I am trying to explain things as simply as possible (which can sometimes be quite difficult).
The best definition I can find is one by Castle, the intrinsic factor is a protein or enzyme like unidentified substance that is secreted by the stomach. This substance is present in both the gastric juice and the gastric mucous membrane. The intrinsic factor is necessary for vitamin B12 to travel through your body properly.
Once vitamin B12 enters your stomach it binds to binding proteins that are in your gastric juices. Since the small intestine is less acidic then other parts of your digestive system this is where the proteins detach from the vitamin B12, allowing the B12 to then bind to the intrinsic factor.
When the intrinsic factor is not present it is extremely difficult, if not impossible, for B12 to travel through the intestines and get to where your body needs it. There is bacteria in your intestine that would feed off the B12 before it was able to get where it needs to go. This is how you can become vitamin B12 deficient, even when you are getting an abundance of it.
To make the protein for the intrinsic factor you need a good supply of different types of amino acids. These usually come from different animal sources, among them meat, cheese and milk. It is easy for a vegetarian to become deficient in vitamin B12 because plant sources don’t produce a variety of amino acids, only one type. Because of this a vegetarian diet may not supply all the raw materials your body needs to make the intrinsic factor.