Intrinsic factor facts for kids

Intrinsic factor (IF), also called gastric intrinsic factor (GIF), is a special protein. It is made by certain cells in your stomach called parietal cells.

IF is super important for your body to take in vitamin B₁₂. Vitamin B12 is also known as cobalamin. Your body needs IF to absorb this vitamin later in the small intestine, specifically in a part called the ileum. In humans, the instructions for making this protein are found in a gene called GIF.

What is Intrinsic Factor?

Intrinsic factor is a type of glycoprotein. This means it's a protein that has sugar molecules attached to it. Think of it like a special key that helps unlock the way for vitamin B12 to enter your body. Without this key, vitamin B12 can't get into your bloodstream properly.

Why is Vitamin B12 Important?

Vitamin B12 is a very important vitamin for your body. It helps your body in many ways:

• It helps make red blood cells. These cells carry oxygen all over your body.
• It helps your nervous system work correctly. Your nervous system includes your brain and nerves.
• It plays a role in making DNA, which is the blueprint for all your cells.

If your body can't absorb enough vitamin B12, you can get sick. This can lead to a type of anemia where you don't have enough healthy red blood cells.

How Does Intrinsic Factor Work?

When you eat foods that contain vitamin B12, like meat, fish, or dairy products, the vitamin travels to your stomach.

1. In your stomach, the intrinsic factor protein is released by the parietal cells.
2. The intrinsic factor then binds very tightly to the vitamin B12. They form a team!
3. This team (intrinsic factor + vitamin B12) then travels down to the small intestine.
4. In the last part of the small intestine, called the ileum, there are special receptors. These receptors recognize the intrinsic factor.
5. The intrinsic factor helps the vitamin B12 pass through the wall of the intestine and into your bloodstream. From there, the vitamin B12 can go to all the parts of your body that need it.

What Happens if There Isn't Enough IF?

Sometimes, a person's stomach might not make enough intrinsic factor. This can happen for different reasons:

• An autoimmune disease where the body's own immune system attacks the parietal cells in the stomach. This is called pernicious anemia.
• Surgery on the stomach, like removing a part of it.
• Certain long-term stomach problems.

If there isn't enough intrinsic factor, even if a person eats plenty of vitamin B12, their body can't absorb it. This leads to a vitamin B12 deficiency. People with this problem might feel very tired, weak, or have nerve problems. Doctors can usually treat this by giving vitamin B12 shots or high-dose supplements.

See also

• Factor intrínseco para niños (In Spanish)