Iron is a trace mineral, and therefore, the body does not need large amounts. Iron prevents anemia and is an essential part of hemoglobin. As they get older, most people need to supplement their iron with products.
Recommended Resources
Anemia and Nutrition: The Importance of Iron
National Anemia Action Council presents this article which stresses the importance of iron to the body for a healthy lifestyle. It delves into why iron is important as well as minimum requirements.
http://www.anemia.org/patients/feature-articles/content.php?contentid=000179§ionid=00015
From Northwestern University comes this item which discusses the physiological functions of iron in the system, what happens when a person is iron deficient, and minimum requirements.
http://www.feinberg.northwestern.edu/nutrition/factsheets/iron.html
The official Vegan Society site contains details about iron and iron supplements, beginning with an outline of what the body requires, absorption, and how important it is to vegans.
http://www.vegansociety.com/References/Nutrition/Iron.aspx
