This is the fifth in the series of reviews developed as part of the
Biomarkers of Nutrition for Development (BOND) program. The BOND
Iron Expert Panel (I-EP) reviewed the extant knowledge regarding
iron biology, public health implications, and the relative usefulness of currently available
biomarkers of
iron status from deficiency to overload. Approaches to assessing intake, including bioavailability, are also covered. The report also covers technical and laboratory considerations for the use of available
biomarkers of
iron status, and concludes with a description of research priorities along with a brief discussion of new
biomarkers with potential for use across the spectrum of activities related to the study of
iron in human health.The I-EP concluded that current
iron biomarkers are reliable for accurately assessing many aspects of
iron nutrition. However, a clear distinction is made between the relative strengths of
biomarkers to assess hematological consequences of
iron deficiency versus other putative functional outcomes, particularly the relationship between maternal and fetal
iron status during pregnancy, birth outcomes, and infant cognitive, motor and emotional development. The I-EP also highlighted the importance of considering the confounding effects of
inflammation and
infection on the interpretation of
iron biomarker results, as well as the impact of life stage. Finally, alternative approaches to the evaluation of the risk for nutritional
iron overload at the population level are presented, because the currently designated upper limits for the
biomarker generally employed (serum
ferritin) may not differentiate between true
iron overload and the effects of subclinical
inflammation.