Before iron can be absorbed, it must be soluble (able to dissolve). Different types of iron are more soluble than others. For example, the heme iron in meat and animal products is easily absorbed and generally not affected by other foods.1
Plant products contain non-heme iron. Vitamin C or other acids and sugars may aid in iron absorption, whereas tannins and phytates may inhibit iron absorption.2 For this reason, absorption of non-heme iron can be helped or hindered by other foods you eat during the same meal.1,3
One type of iron that is not immediately soluble when ingested is carbonyl iron. Carbonyl iron can only be absorbed when it is converted to soluble ferrous iron by gastric acid.4
- Finch CA, Cook JD. Iron deficiency. American Journal of Clinical Nutrition. 1984 Mar;39(3):471-7.
- Barton JC. Iron deficiency. In Rakel RE, Bope ET. Conn's Current Therapy, 2008. Amsterdam, The Netherlands: Saunders/Elsevier, 385-389.
- Recommendations to prevent and control iron deficiency in the United States [Internet]. Centers for Disease Control and Prevention; 1998 Apr 3 [accessed 2008 Apr 9]. Available from: http://www.cdc.gov/mmwr/preview/mmwrhtml/00051880.htm.
- Gordeuk VR, Brittenham GM, McLaren CE, Hughes MA, Keating LJ. Carbonyl iron therapy for iron deficiency anemia. Blood 1986 Mar;67(3):745-752.
