Absorption of iron
Ferrous iron (Fe2+) is much more soluble than Ferric iron (Fe3+), which makes it more absorbable.
This is an important factor when iron enters the environment of the stomach and small intestine.
After ingestion of iron, whether from our diet or in a supplement form, the pH level of the stomach affects how well the iron is digested.
Interaction with food and drink, and other substances like medication, has an impact on the amount of iron that moves on into the intestinal area and how much is left behind. Iron that remains in the stomach may lead to gastrointestinal side effects.9
From the stomach, iron travels to the small intestine, where absorption occurs.
Saunders, A.W., Craig, W.J., et al. Iron and vegetarian diets. MJA Open, 2012, 2:11-16