GI 18 Flashcards
What are the water soluble vitamins?
- Vitamin C
* B Complex vitamins
Where are the majority of water soluble vitamins absorbed?
In the first part of the small intestine
What is the absorption of majority of water soluble vitamins coupled to?
Specific sodium cotransporters
What is Folate absorption dependant on?
A proton-coupled folate transporter
Where does B12 absorption occur?
In the ileum
What does B12 absorption require?
Binding to a protein called intrinsic factor
What are the fat soluble vitamins?
Vitamins A, D, E, and K
How are fat soluble vitamins typically consumed?
Bound as esters
What must happen to the esters bound to fat soluble vitamins?
The esters must be hydrolyzed in the gut lumen
How does uptake of free fat soluble vitamins usually occur?
Via specific transport proteins
What happens to free fat soluble vitamins after being absorbed?
They are re-esterified and packaged into chylomicrons
Where is the majority of the body’s iron present?
In hemoglobin
How must lost iron be replaced?
From the diet
What does tight regulation of iron absorption mean?
That the amount taken up matches what is lost so not a lot is absorbed by the body
What is the form of iron of most of the iron in the diet?
Fe3+, the ferric form
