Iron deficiency is estimated to affect over two billion people worldwide. It is one of the few nutritional deficiencies that remains common in developed countries where it predominantly affects women, particularly during pregnancy. The setting of accurate Recommended Dietary Intakes (RDIs) for iron is, therefore, important for population health and nutritional well-being. We have recently examined the method used to calculate the RDI for iron and believe the current guidelines may, in fact, encourage iron deficiency. The RDI for iron is based on an estimate of the proportion of dietary iron absorbed, which is used to determine the amount required to replace obligatory daily losses. Currently, the amount absorbed is based on that of a person with normal functional iron levels, but minimal storage iron as indicated by a serum ferritin (SF) of 15 μg/L i.e. someone who is iron deficient but not anaemic. However, the amount of iron absorbed from the diet is inversely regulated by body iron stores. Therefore, basing the RDI for iron on the absorption rate of an individual with a SF of 15 µg/L will encourage iron deficiency, as those with a higher SF will not absorb enough iron to replace obligatory losses. Body iron stores would fall until a SF of 15 µg/L is reached, at which point iron absorption would balance iron losses. Using recently published estimates of iron absorption based on a target SF of 70 µg/L, we have re-calculated the RDI for iron and found that it increases from 18 mg/day to 33 mg/day for premenopausal women. These estimates represent a significant increase in the RDI and suggests that public health policy should be re-evaluated to better reflect population iron requirements.