New tools in studies on iron nutrition. Principles, applications and consequences

New tools to study iron nutrition are reviewed in this article. An algorithm is devised to predict dietary iron absorption from meals and diets based on contents of dietary factors influencing heme and nonheme iron absorption. Sum of iron absorption from single meals was found to equal total dietary iron absorption. Observed relations between iron absorption, iron requirements and iron stores can be described as an exponential equation allowing calculations of any stationary state. After integration of the equation, rate of changes in iron stores, or hemoglobin iron deficits, can be calculated when any factor is modified. Control of dietary iron absorption is extremely efficient, effectively preventing iron overload in all who are not genetically predisposed. Suggested relations between iron stores and disease may rather be independent relations between diseases and serum ferritin.