Which of the following is true about iron absorption? a. It ...

[KWilfred]

Which of the following is true about iron absorption?
 
  a. It occurs primarily in the stomach.
  b. Phytates and tannates enhance its absorption.
  c. Ascorbic acid inhibits its absorption.
  d. It must be in ferrous form for absorption.

Question 2

The serum ferritin is used more often than bone marrow or liver biopsies to assess iron stores because it is:
 
  a. A more direct measurement
  b. More accurate
  c. More precise
  d. Less invasive

[bblaney]

Answer to Question 1

ANS: D
Iron must be in the ferrous (divalent) state for absorption, which occurs primarily in the duodenum and upper jejunum. Any dietary iron that is in the ferric form is reduced to the soluble ferrous form by a duodenum-specific cytochrome blike protein. Ascorbic acid enhances absorption, whereas phytates and tannates inhibit absorption.

Answer to Question 2

ANS: D
The measurement of ferritin is performed on a serum sample; therefore it requires nothing more than a venipuncture to obtain a blood specimen. It is proportional to the iron in stores, but it is not a more direct measurement. In fact, a bone marrow biopsy followed by staining with Prussian blue to assess iron stores (in the form of hemosiderin) is perhaps the best measurement of iron stores that are readily available for use in hemoglobin synthesis. This is much more invasive.

[KWilfred]

TYSM

[nyrave]

Gracias!