The long term effects of soy-based formula on isoflavone concentration of plasma and urine, and growth and recognition development at 10 and 20 months old infants

Author: Ryowon C, Lee JY, Lee HO, Chung SJ, Cho MR, Kim JY, Lee IH
Publication: Asia Pac J Clin Nutr. 2004;13(Suppl):S123

There’s some controvery about the possible adverse health impact of soy isoflavones on babies and small children. Formulas based on soy proteins are widely used, mainly by vegan babies and babies who are allergic to cow’s milk.

The purpose of this study was to investigated the effects of soy-based formulas on isoflavones on the development and recognition of 10 to 20 months old babies. The concentration of isoflvaones were measured in the plasma and urine. In total 33 healthy babies participated in the study. The babies we divided in 4 groups:

  • Group 1 (7 babies) received during 10 months only breast milk
  • Group 2 (6 babies) first received breast milk for only 4 months, thereafter soy-based formula
  • Group 3 (9 babies) received during 10 months soy-based formula
  • Group 4 (8 babies) were fed during 10 months with cow’s milk-based formula

The following anthropometric assessments were carried out: gross motor, fine motor, personal social, language, cognitive adaptive. The weight, height, head and chest circumference were measured. There were no significant differences found for these factors between the different groups.

The levels of isoflavones (daidzein and genistein) were measured in the plasma and urine. The plasma isoflavones levels in group 2 and 3 were significantly higher than those of other groups. Also, urine concentrations of daidzein and genistein were significantly higher in group 2 and 3.

It was concluded that the obtained data suggested that soy-based formula could be used for long-term feeding of babies.