Cortical Responses to Speech Sounds in 3- and 6-Month-Old Infants Fed Breast Milk, Milk Formula, or Soy Formula

Abstract

Controversy exists about the safety of soy formula, with the main concern relating to potential estrogenic effects of soy protein. Since estrogens influence early brain development, we compared behavioral development and cortical responses (event-related potentials; ERPs) to speech sounds in infants fed either breast milk or formula (milk- or soy-based). Across-groups ERP measures were generally similar and behavioral measures were within normal ranges, suggesting no important influences of soy formula on behavioral development and brain function during the study period. Analyses relating ERP and behavioral measures revealed diet- and gender-specific emphases that may reflect differences in developmental trajectories of brain–behavior relationships.

Notes

This work was supported by USDA CRIS 6251-51000-002-03S.

^sBF > SF (p < .05);

^tBF > SF (p < .01);

^uBF > MF (p < .05);

^vSF > MF (p < .05).

¹Mom's IQ: indexed by Wechsler Abbreviated Scale of Intelligence (WASI) full scale IQ.

²SES: Social Economic Status measured by Hollingshead (1975) Four-Factor Index of Social Positions.

³PROCESS 3mon/6mon: Pediatric Review of Children's Environmental Support and Stimulation data collected at 3 and 6 month visits.

^a p < .05;

^bp < .01;

^cp < .001.

^a p < .05;

^b p < .01.

^a p < .05;

^bp < .01;

^cp < .001.

^a p < .05;

^b p < .01.

1. To avoid repetition in the text, the degrees of freedom associated with gender-related regression analyses are as follows: BF males (3,16), females (3,16); MF males (3,25), females (3,18); SF males (3,14), females (3,17).