Ferrous Sulfate Is More Bioavailable among Preschoolers than Other Forms of Iron in a Milk-Based Weaning Food Distributed by PROGRESA, a National Program in Mexico,

Abstract

After 1 y of distributing a milk-based fortified weaning food provided by the Mexican social program PROGRESA, positive effects on physical growth, prevalence of anemia, and several vitamin deficiencies were observed. There was no effect on iron status, which we hypothesized was related to the poor bioavailability of the reduced iron used as a fortificant in PROGRESA. The objective of this study was to compare the iron bioavailability from different iron sources added as fortificants to the weaning food. Children (n = 54) aged 2-4 y were randomly assigned to receive 44 g of the weaning food fortified with ferrous sulfate, ferrous fumarate, or reduced iron + Na(2)EDTA. Iron absorption was measured using an established double-tracer isotopic methodology. Iron absorption from ferrous sulfate (7.9 +/- 9.8%) was greater than from either ferrous fumarate (2.43 +/- 2.3%) or reduced iron + Na(2)EDTA (1.4 +/- 1.3%) (P < 0.01). The absorption of log-(58)Fe sulfate given with the iron source correlated with serum ferritin (s-ferritin) concentration (n = 13, r = 0.63, P = 0.01) and log-(57)Fe absorption (reference dose) (n = 14, r = -0.52, P = 0.02). Absorption from ferrous fumarate and reduced iron + Na2EDTA did not correlate with s-ferritin or absorption of (57)Fe. The recommended daily portion of the fortified complementary food provides an average of 0.256, 0.096, 0.046 mmol (1.44, 0.54, and 0.26 mg) of absorbed iron, if fortified with sulfate, fumarate and reduced iron + Na(2)EDTA, respectively. Ferrous sulfate was more bioavailable than either ferrous fumarate or reduced iron + Na(2)EDTA when added to the milk-based fortified food and more readily met the average daily iron requirements for children 2-3 y of age.

A comparison of the bioavailability of ferrous fumarate and ferrous sulfate in non-anemic Mexican women and children consuming a sweetened maize and milk drink

“…These results thus differ from earlier studies in infants in Bangladesh (Sarker et al, 2004) and Mexico (Perez-Exposito et al, 2005), which reported that iron absorption from complementary foods fortified with ferrous fumarate was only one-third of that from ferrous sulfate. There are several potential explanations for these differences.…”

“…The results from the Bangladesh study (Sarker et al, 2004) would be most consistent with this hypothesis, Relative bioavailability of ferrous fumarate M Harrington et al as all the Bangladeshi children were iron-deficient anemic, compared with none in the present study. In the study by Perez-Exposito et al (2005), 11% of the Mexican children were anemic and 30% were iron deficient compared with iron deficiency in 39% of women, 6% of infants and 5% of children in the present study. The absolute absorption of iron from the iron fortified test meals in the present study was higher in women than in infants or young children.…”

“…These studies showed that iron absorption from ferrous fumarate, a poorly water-soluble iron compound that is also soluble in dilute acid, was equivalent to that from ferrous sulfate (Hurrell et al, 1989Fidler et al, 2003). However, recent studies in Bangladesh with infants consuming a wheat-soy infant cereal, and in Mexico with young children consuming a maltrodextrin/milk-based complementary food, reported that iron absorption from ferrous fumarate was only 25-35% that from ferrous sulfate (Sarker et al, 2004;Perez-Exposito et al, 2005) and that the RBV of ferrous fumarate in young children may thus be only around 30.…”

“…One possibility is that iron status of the subjects could influence RBV (Moretti et al, 2006). In the adult studies, subjects were mainly iron replete, whereas all of the Bangladeshi children were iron-deficient anemic (Sarker et al, 2004) and some of the Mexican children were iron deficient (Perez-Exposito et al, 2005).…”

In Vitro Dissolution Profile of Two Commercially Available Iron Preparations

“…Previous evidence suggests that different iron salts show similar tolerability in clinical use. [22] In two studies comparing the absorption of ferrous sulfate and ferrous fumarate from fortified milk-based drinks, one study found that ferrous sulfate was better absorbed than ferrous fumarate, [23] while absorption of ferrous sulfate and ferrous fumarate did not differ significantly in the second study. [24] Given the significant effects that the type of salt may have on in vitro dissolution, ferrous sulfate-containing supplements such as Folifer Ò may therefore be a better choice for iron/folic acid supplementation in individuals at risk of iron/folate deficiencies, such as pregnant and lactating women.…”