Iron is a metal frequently occurring in our surroundings, present almost everywhere in the earth and playing a prominent role in our everyday life. Whether it is as the iron in the blade of a kitchen knife or the structural iron in a car, most of us appreciate and recognize that iron plays a central role in our lives. Fewer although recognize that iron is also very essential for biological life in itself, life in the plant kingdom, where iron is essential for the function of the photosynthesis processes, or in the animal kingdom where iron is essential for the function of haemoglobin in red blood cells, and as a central component in many critical enzymes in the body.
Despite the abundance of iron in our surroundings, large groups of humans frequently display various signs of either absolute or functional iron deficiency. This is caused by a combination of iron loss and the general difficulties for biological system to absorb iron at a sufficient rate. Despite iron being so abundant, absolute or functional iron deficiency is surprisingly frequent and neglected in many clinical conditions. Many human disorders and diseases directly or indirectly cause loss of iron, which by themselves or in combination with malnutrition results in iron deficiency and in the end iron deficiency anemia.