The VIII Nestle Nutrition Conference was organized by the Nestle Nutrition Fund of the Mexican Health Foundation in cooperation with the National Institute of Medical Sciences and Nutrition Salvador Zubiran. The conference was held on November 22–23 of 2010 in Mexico City and was entitled “Iron deficiency (ID) and iron deficiency anemia (IDA) in early infancy; etiology, consequences, prevalence, and prevention”.
ID and IDA affect billions of people worldwide, especially women of reproductive age, pregnant women, and young children. The capacity of iron to participate in reduction and oxidation reactions, as well as its essential role in oxygen transport in children, make it a critical nutrient for every tissue, including the brain. Infants have expanding muscle mass and red blood cell mass – two tissues especially rich in iron – making them an age group with high iron needs. The evidence that ID and IDA have deleterious and long-term effects on child cognition and behavior has been a motivation for clinical and public health studies in order to prevent and treat ID and IDA. The current literature in this area allows several well-documented statements:
- • ID in infancy is a worldwide public health problem, the magnitude of which is higher in less developed areas.
- • ID in infancy has lasting and, in some instances, permanent deleterious effects on the infant's future growth, development, and well-being.
- • There are screening and diagnostic tools as well as effective preventive and corrective measures, to deal with ID in the infant older than 6 months.
However, our knowledge of and methods to contend with ID in infants younger than 6 months of age are less clear. The information presented at the VIII Nestle Nutrition Conference and published in this supplement of Nutrition Reviews is aimed at advancing knowledge of this health problem in several aspects:
- • The role of prepregnancy and pregnancy maternal iron status on fetal iron endowment.
- • The regulation of fetal iron deposits by the placenta.
- • Strategies to prevent early ID through improved care, like longer timing of umbilical cord clamping and early introduction of iron-rich complementary foods.
- • Recent experiences with population interventions aimed at improving reproductive health and reducing the burden of early ID.
The first paper, by Fernando Viteri, presents a detailed review of the field organized into three parts: 1) maternal iron status and health prior to and during gestation, 2) the placenta and its role in transferring iron to the fetus, and 3) interventions to improve the iron status of mothers and newborns prior to and during pregnancy. Dr. Viteri's review introduces the rest of the papers in the supplement and explains the context in which the different contributions are related to IDA in early infancy.
Harry McArdle et al. review their experimental work, which suggests the fetus, and not the mother, regulates iron uptake and transfer across the placenta, and how these processes interact and modulate the maternal iron metabolism. The article by Theresa Scholl addresses the role of fetal growth and length of gestation on the infant's iron endowment at birth. She concludes that the endowment reflects the mother's iron status during pregnancy and suggests that supplemental iron should be started before pregnancy. Camilla Chaparro discusses the physiological basis for the impact of cord clamping time on iron endowment and its importance in determining iron status later in infancy. Ekhard Ziegler presents two papers: the first shows that the feeding of cow's milk to infants and preschoolers is strongly associated with diminished iron stores and an increased probability of ID (his second paper is described below). Michael Georgieff considers that early ID not only affects brain and behavioral function during the period of ID, its influence continues many years after the deficiency is reversed. He reviews recent studies that demonstrate long-term genomic changes suggesting that the regulation of brain function is fundamentally altered despite prompt and successful treatment of the deficiency. Blair Cameron and Lynnette Neufeld summarize current estimates on the prevalence of ID and IDA in children younger than 2 years and review the strengths and weaknesses of currently available indicators of ID in children. The paper of Michael Hambidge et al. includes a description of two major randomized controlled trials of meat as a first and regular complementary food, which may help prevent ID and IDA. Maureen Black and her collaborators analyze longitudinal studies from infancy through adolescence and early adulthood; they conclude that the socioemotional development of children is uniquely vulnerable to ID/IDA, perhaps associated with shared neural pathways, and that the effects of early ID may be irreversible. The final two articles address the outcome of strategies to prevent ID and IDA: One is the second paper of Ekhard Ziegler et al., which discusses three studies aimed at finding ways to improve iron status of breastfed infants and to prevent ID. The final article, by Jacques Berger et al., describes two ongoing interventions that attempt to improve reproductive health and iron status during pregnancy, as well as other possible strategies, such as preconceptual iron supplementation.
The high quality of the articles in this supplement, coupled with the scope and experience of their authors, have enriched our perspective of ID in infants and thrown light on some strategies to contend with this global public health problem.