Absorption of heme iron

Area of Science:

• Nutritional Science
• Gastroenterology
• Biochemistry

Background:

• Heme iron, abundant in meat, is absorbed more efficiently than inorganic iron.
• Dietary iron absorption mechanisms significantly impact iron deficiency prevalence.
• Meat consumption correlates with lower rates of iron deficiency.

Purpose of the Study:

• To elucidate the distinct absorption pathway of heme iron compared to inorganic iron.
• To understand the molecular mechanisms governing heme iron uptake and processing in the small intestine.
• To identify factors influencing heme iron bioavailability.

Main Methods:

• Analysis of heme iron absorption in the small intestine.
• Investigation of heme iron's interaction with intestinal absorptive cells.
• Enzymatic studies on heme degradation within enterocytes.
• Role of specific proteins (mobilferrin, paraferritin) in iron handling.

Main Results:

• Heme iron is absorbed intact as a metalloporphyrin, potentially via vesicular transport.
• Globin degradation products maintain heme solubility for absorption.
• Heme oxygenase cleaves the porphyrin ring within absorptive cells.
• Released iron shares a common mucosal transfer pathway with inorganic iron.

Conclusions:

• Heme iron absorption is a distinct and efficient process compared to inorganic iron.
• Understanding heme iron's pathway can inform strategies to combat iron deficiency.
• The intestinal cell employs specific mechanisms for heme iron uptake, processing, and transfer.