Strategies for the prevention of iron deficiency: iron in infant formulas and baby foods

Iron administration reduces airway hyperreactivity and eosinophilia in a mouse model of allergic asthma

The prevalence of allergic diseases has increased dramatically during the last four decades and is paralleled by a striking increase in iron intake by infants in affluent societies. Several studies have suggested a link between increased iron intake and the marked increase in prevalence of allergic diseases. We hypothesized that the increased iron intake by infants offers an explanation for the increased prevalence of allergic disease in industrialized societies during the past four decades. A well-established mouse model of ovalbumin (OVA)-driven allergic asthma was used to test the effects of differences in iron intake and systemic iron levels on the manifestations of allergic asthma. Surprisingly, iron supplementation resulted in a significant decrease in airway eosinophilia, while systemic iron injections lead to a significant suppression of both allergen-induced airway eosinophilia and hyperreactivity compared to placebo. In contrast, mice fed on an iron-deprived diet did not show any difference in developing experimentally induced allergic asthma when compared to those fed on an iron-sufficient control diet. In contrast to our hypothesis, airway manifestations of allergic asthma are suppressed by both increased levels of iron intake and systemic iron administrations in the mouse model.

Iron deficiency anemia following prenatal nutrition interventions

PURPOSE

Iron deficiency anemia (IDA) during pregnancy and infancy is still common in developed countries, especially in low-income groups. We examined the prevalence of anemia and IDA in healthy low-income pregnant women participating in the Early Childhood Initiatives (ECI) program, and in their infants when they reached six months of age.

METHODS

Pregnant women were recruited by nutritionists. In mothers, hemoglobin (Hb), mean corpuscular volume, and serum ferritin (SF) were measured at 36 +/- 2 weeks of gestation. In infants, Hb, mean corpuscular volume, SF, serum iron, total iron binding capacity (TIBC), and transferrin saturation (TS) were measured at six months of age. Thirty-one mother-infant pairs participated.

RESULTS

Among the 31 pregnant women participating in the ECI program, six (19.4%) were anemic (Hb <110 g/L) and five (16.1%) suffered from IDA (Hb <110 g/L and SF <10 microg/L). Among infants, seven of 23 (30.4%) were anemic (Hb <110 g/L) and five of 23 (21.7%) suffered from IDA (Hb <110 g/L plus two of the following: TIBC >60 micromol/L, SF <10 microg/L, serum iron <5.3 micromol/L, TS < or = 15%).

CONCLUSIONS

The prevalence of anemia in this group of low-income pregnant women is comparable to that in privileged women. The prevalence of IDA in infants is comparable to that observed in other high-risk groups. Effective strategies are needed to prevent IDA in vulnerable groups.

Clinicolaboratory findings and treatment of iron-deficiency anemia in childhood

One of the major causes of anemia in childhood worldwide is iron deficiency. Its prevalence depends mainly on age, being higher in infancy and adolescence. Its etiology varies, but poor iron diet is considered the commonest causative factor. Better tactics may be needed, like the targeted screening of children who belong to high-risk groups, to eradicate childhood iron deficiency. The amount of the body iron regulates its absorption from the gut through mechanisms that are still poorly understood. Early identification of iron deficiency is essential for the prevention not only of anemia but also the numerous and long-term consequences caused by the lack of iron. Many tests are available for the diagnosis of the disease. Some of them seem very promising for the early detection of iron deficiency, but further research is needed before they become widely acceptable in clinical practice. Treatment is based on oral iron salts, which do not have any serious side effects.

Iron and breastfeeding

Given the importance of iron nutrition during the first year of life, there are surprisingly few true, randomized, controlled studies addressing this issue; however, it seems that iron deficiency is unlikely in full-term, breastfed infants during the first 6 months of life because these infants' body iron stores are sufficient to meet requirements. After this time, many infants exhaust their iron stores and become dependent on a secondary dietary iron supply. Although iron deficiency is a significant nutritional problem worldwide, most of the adverse effects of iron deficiency in this age group are hypothetical and rely on extrapolation from animal studies or studies at different ages. This, however, also is true of most of the adverse effects of iron excess in this age group. Given this uncertainty, it seems prudent to use the lowest dose of iron that prevents iron-deficiency anemia. Currently, the best evidence is that this is achieved by prolonged breastfeeding, avoidance of unfortified formulas and cow's milk, and the introduction of iron-fortified and vitamin C-fortified weaning foods at approximately 6 months of age. Despite much research, there are many areas of uncertainty regarding iron supplementation of infants, including that: 1. The optimal age for introducing iron-fortified supplemental foods is poorly defined and should be further evaluated. 2. The natural history of iron deficiency and iron-deficiency anemia during the first year of life is unclear, as are the possible long-term effects of this, especially on developmental outcome. 3. The biologic variability among infants and among their mothers that allows many infants who do not receive iron-fortified foods to prevent iron deficiency while receiving only human milk throughout the first year of life is intriguing and warrants additional study. 4. The iron requirements of small-for-gestational-age, term infants are unknown. Their iron requirements are likely to be higher than those of average term infants, but whether iron supplements are required is unclear. 5. The optimum amount of dietary iron in the weaning diet needs to be further defined. Similarly, the optimal source and amount of iron in infant formulas given to infants who receive a mixture of human milk and formula is unclear.

Continuation of the decline in prevalence of anemia in low-income infants and children in five states

OBJECTIVE

To examine whether there is a continuation of the decline in prevalence of anemia among low-income infants and children 6.0 to 59.9 months old from the early 1980s to the mid-1990s.

STUDY DESIGN

Cross-sectional trend analysis of data from the Centers for Disease Control and Prevention's Pediatric Nutrition Surveillance System from the 5 states (Colorado, New Mexico, Oklahoma, Utah, and Vermont) that have been using the same laboratory method for anemia screening since 1984 or earlier.

RESULTS

The overall prevalence of anemia decreased substantially in each state from the early 1980s to the mid-1990s as follows: Colorado by 52%; New Mexico by 75%; Oklahoma by 67%; Utah by 57%; and Vermont by 48%. In each state, the prevalence of anemia declined for children of different age groups, birth weights, genders, type of pediatric care visit (screening or follow-up), and most race/ethnic groups.

CONCLUSIONS

The decline in the prevalence of anemia initially observed in the 1980s continued well into the 1990s. This decline is likely attributable to better iron nutrition related to greater usage of iron-fortified products and possibly better iron bioavailability in some of the food products.

59Fe is retained from an elemental 59Fe powder supplement without effects on 65Zinc, 47Calcium and 67Copper in young pigs

In vivo counting with the use of a germanium detector evaluated the retention of an elemental 59Fe powder supplement while measuring potential interactions with zinc, calcium and copper. Effects of dietary iron and zinc on in vivo retentions of 59Fe, 65Zn, 67Cu and 47Ca were studied in young pigs. In Experiment 1, 4-d-old piglets fed a cereal-based diet were randomly assigned to one of four treatment groups (2 x 2 factorial arrangement, n = 5 per group). Variables were dietary iron source (either elemental iron or FeSO4, each at 100 mg iron/kg diet) and the dosage form of radioactive iron (either elemental 59Fe powder or 59FeSO4). Experiment 2 (2 x 3 factorial arrangement) was performed using two levels of iron (100 and 200 mg/kg, as elemental iron) and three levels of zinc (25, 50 and 100 mg/kg). Piglets were also dosed with 47Ca, 65Zn and 67Cu; all radioisotopes were measured for 8 d. Apparent absorption of elemental 59Fe powder was 13 +/- 1%, whereas 59Fe sulfate was significantly (P < 0.05) higher at 26 +/- 1%. The FeSO4 diet decreased 65Zn retention in Experiment 1, in contrast to the elemental iron diet, which did not have this effect in either experiment. Apparent 65Zn absorption averaged 44 +/- 2, 35 +/- 1 and 27 +/- 2% for the three levels of zinc (25, 50 and 100 mg/kg), respectively. Retention of 47Ca was not affected by dietary iron or zinc; retention of 67Cu was not affected by dietary iron. The data demonstrate good bioavailability of elemental iron without effects on zinc, copper and calcium.