Abstract
ABSTRACT Objective: This study aimed to compare the intestinal absorption of iron and calcium between soy-based and cow's milk-based infant formulas in weanling rats. Methods: Twenty male Wistar rats, twenty-one days old on the first day of weaning, were used in this experiment, divided in two Groups, one Group was fed soy protein-based infant formula the other, cow's milk protein-based infant formula. During the study period (ten consecutive days) the animals received food and water ad libitum. Hematocrit and hemoglobin were evaluated on the first, fifth, and tenth days by the Wintrobe and cyanomethemoglobin methods. Feces and urine were collected, beginning on the fifth day, for three consecutive days. On the tenth day, hepatic iron content was also analyzed. Hepatic iron as well as fecal and urinary iron and calcium analyses were performed using an atomic absorption spectrophotometer. At thirty-one days of age, the animals were anesthetized with ketamine and xylazine and sacrificed by exsanguination via the vena cava. Results: The final concentration of hemoglobin in the group soy-based infant formula and milk-based infant formula were: 10.3±1.3g/dL and 10.9±1.0g/dL (p=0.310). The apparent absorption of iron and calcium, in that order, were: 73.4±10.2% and 70.2±9.5%; 97.2±0.7% and 97.6±1.0% (p=0.501; p=0.290). The apparent calcium retention was: 88.4% ±2.2 and 88.6±2.6% (p=0.848). Hepatic iron content was: 522.0±121.1mg/g and 527.8±80.5mg/g (p=0.907) . Conclusion: Intestinal iron and calcium absorption from soy-based infant formula is similar to that from milk-based infant formula in weanling rats.
Highlights
Soy-based formulas have been used in infant nutrition because of their relatively low cost and their acceptance by infants[1]
Before starting the experimental diets, there was no statistically significant difference between groups with respect to hemoglobin or hematocrit (p>0,05). This similarity between groups was maintained after the exclusion of one animal in each group that did not complete the study by reason of death after anesthesia without apparent cause
The iron and calcium intakes were similar in both groups (p>0,05)
Summary
Soy-based formulas have been used in infant nutrition because of their relatively low cost and their acceptance by infants[1]. Despite very limited indications for these formulas, they are used for a large number of infants worldwide[2]. The indications for the use of a soy formula are restricted to several cases: proven serious and persistent intolerance to lactose; galactosemia; children from vegetarian families who cannot be breastfeed and whose parents wish to avoid animal-derived protein formulas for religious, philosophical or ethical reasons; and immunoglobulin-mediated allergy to cow’s milk protein in children who are not sensitized to soy[1,2]. The composition of soy proteins is very complex and differs from the cow’s milk proteins used in infant formulas[3]. Several publications have reviewed the potential adverse effects of the use of soy formulas, especially regarding phytate, aluminum, manganese, and phytoestrogen content. Data for other outcome variables are limited, but they suggest no change in visual acuity, cognitive development, response to vaccination, or number of immune cells[1,2,4,5,6,7,8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
