Iron deficiency, and its more severe manifestation iron deficiency anaemia, are major global health problems affecting more people worldwide than any other condition. They are most common in young children, adolescents and women of child-bearing age and occur because the body cannot absorb enough iron from the diet to meet body requirements or to compensate for iron losses. The causes of iron deficiency are often multifactorial, with the most common being insufficient dietary intake, the rapid growth that occurs during infancy and adolescence, and blood loss through menstruation or gastrointestinal bleeding. Iron deficiency, and particularly iron deficiency anaemia, can lead to impaired cognitive development in children, and diminished work capacity and mental function in adults. Iron deficiency anaemia in pregnant women is associated with low birth weight, prematurity and maternal morbidity.
Iron deficiency affects more than 2 billion people worldwide, with over 1 billion of those developing iron deficiency anaemia. The global economic costs are enormous, with estimates suggesting that treating iron deficiency anaemia would raise national productivity by 20% in some countries. Although the majority of affected individuals reside in developing nations, iron deficiency is the only nutritional deficit present at significant levels in developed countries. Estimates from Australia suggest that 8% of preschool children and 12% of pregnant women are iron deficient. The figures are far more concerning in Indigenous Australians. Up to 90% of Aboriginal children have iron deficiency anaemia between the ages of 6 and 24 months, 79% of children between the ages of 5 and 14 are iron deficient, and 72% of women over the age of 14 are iron deficient.
The most widely used and most cost effective treatment for iron deficiency is oral iron supplementation. Unfortunately, currently available supplements can lead to gastrointestinal side effects, often causing affected individuals to cease treatment. In addition, iron supplements trigger unfavourable changes in the intestinal microbiome. Intravenous iron infusions are being used more frequently for the treatment of iron deficiency, particularly if severe. While effective, infusions are invasive and can lead to low blood phosphate levels and permanent localised skin discolouration. Thus, there remains a need for a well-tolerated, safe and effective oral iron supplement for treating iron deficiency.