Iron is a most versatile element. It is essential to many of the enzymes that are the engines for life, and in mammals is also used to carry oxygen on hemoglobin in blood. Remember Popeye and his spinach: all that iron made him strong.
But the very quality that makes iron so useful also makes it dangerous. Iron can easily lose or gain one electron going from the ferrous (Fe++) to the ferric (Fe+++) state, back and forth indefinitely. This is how it carries oxygen, for example.
It also means it can be a potent pro-oxidant – it catalyzes the production of free radicals which can destroy cells and tissue, and thereby contribute to cancer and heart disease. (Watch: The easiest quinoa recipe ever. Post continues after video.)
Life forms like us have developed extensive defense mechanisms that allow us to use iron for life’s work while keeping it away from anywhere it is not immediately needed within cells and in the body in general.
Iron fortification sweeps the world
Severe iron deficiency is a health problem in much of the world, but in the US it is uncommon.
The recommended daily allowance for adult men is about 8mg per day, and for adult women under 50 it is about 18mg per day (for pregnant women 27mg per day is recommended). Recommended daily allowances are higher for vegetarians. Most of us get all the iron we need from our diet. And some foods are supplemented with iron.
During the first half of the 20th century, both medical and public health forces began to aggressively promote iron fortification of food to fight iron-deficiency anemia, particularly in the developing world where the problem was most acute and as much as half the population of some areas fit the definition of anemia.