This iron-deficiency theory was first postulated in the 1930's by English scientist Joseph Hart.

CNN: Topical waters

More than five million children in 15 developing countries have received sachets of vitamin and mineral powders that have been approved by UNICEF and the World Health Organization as a cost-effective treatment for iron deficiency.

FORBES: Three Great Examples of Shared Value in Action

Cutting the umbilical cord immediately after birth - currently standard practice - puts the baby at risk of iron deficiency, experts say.

BBC: Cutting cord early 'risk to babies'

Koch's cardiologist wanted to keep a closer eye on the 88-year-old, who was also showing an iron deficiency, spokesman George Arzt said.

WSJ: Former NYC mayor Koch moved to intensive care