Factors affecting iron absorption in the human body

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Body needs
A normal person with normal haemoglobin levels absorbs only 2-10% of dietary non-
heme iron and 23% of heme iron. Iron deficient individuals may absorb as much as a
third of dietary iron from heme and a fifth from non-heme. Need for iron is increased
with exercise because the production of red blood cells increases.

Form of iron
Ferrous iron is absorbed better than the ferric iron. Organic acids such as vitamin C
moderately increase non-heme absorption by adding an electron to ferric iron (Fe3+)
yielding ferrous iron (Fe2+). Vitamin C then forms a complex called chelate with Fe 2+
thereby enhancing absorption. As such iron supplements should be taken together
with vitamin C rich drinks such as fresh orange juice.

Composition of meal
When meat is eaten with a vegetable and grain products, the absorption of non heme
iron present is improved. A protein factor in meat, fish and poultry(MFP factor)
facilitate non heme absorption. This factor appears to contain amino acids such as
cysteine that bind iron to enhance absorption.

Acid in the stomach
Acid also plays an important role in iron absorption by promoting the conversion of
Fe3+ to Fe2+ and by solubilizing non heme iron. The decreased production of stomach
acids experienced by many elderly people can lower their iron absorption and
ultimately their body stores of iron.

Dietary factors
Several dietary factors interfere with the body’s ability to absorb iron and these
include;
- Phytic acid and oxalic acid in vegetables which bind iron thus reducing
its absorption.
- Dietary fibre intakes above 35g/day bind iron and other trace elements.
- Polyphenols such as tannins found in tea and related substances found in coffee also reduce iron absorption. People trying to rebuild iron stores are advised to reduce coffee and tea consumption, particularly meal times.
- Calcium supplements in amounts greater than 300 mg/d can reduce iron absorption. Calcium supplements should be taken several hours before or after an iron rich meal.

Titany answered the question on November 8, 2021 at 06:03

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Factors affecting iron absorption in the human body

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