Although soy formula has been reported to support normal development, concerns exist regarding potential adverse developmental effects of phytochemicals associated with soy protein. This study characterized developmental status (mental, motor, and language) of breastfed (BF), milk-based formula–fed (MF), or soy protein–based formula–fed (SF) infants during the first year of life.
Healthy infants (N = 391) were assessed longitudinally at ages 3, 6, 9, and 12 months. Development was evaluated by using the Bayley Scales of Infant Development and the Preschool Language Scale-3. Mixed effects models were used while adjusting for socioeconomic status, mother’s age and IQ, gestational age, gender, birth weight, head circumference, race, age, and diet history.
No differences were found between formula-fed infants (MF versus SF). BF infants scored slightly higher than formula-fed infants on the Mental Developmental Index (MDI) score at ages 6 and 12 months (P < .05). Infants who were breastfed also had higher Psychomotor Development Index scores than SF infants at age 6 months and slightly higher Preschool Language Scale-3 scores than MF infants at ages 3 and 6 months (P < .05). In addition, BF infants had a lower probability to score within the lower MDI quartile compared with MF infants and a higher likelihood to score within the upper quartile for the MDI and Psychomotor Development Index compared with SF infants.
This unique study showed that all scores on developmental testing were within established normal ranges and that MF and SF groups did not differ significantly. Furthermore, this study demonstrated a slight advantage of BF infants on cognitive development compared with formula-fed infants.
Comments
Skewed Soy Studes
In my recent book on Regulating Infant Formula I pointed out the alarming inadequacy of studies relating to the impacts of soy-based infant formulas on children's health and development (Kent 2011, 25-27). In that context I said:
"One report from defenders of soy-based infant formula acknowledges, "some child-advocacy groups claim that consuming soy-based formula could accelerate puberty and cause developmental and reproductive abnormalities and thyroid disorders later in life." It then describes a major six-year study funded by the U.S. Department of Agriculture to assess the "long- term health effects of soy infant formula (Agricultural Research Service 2004; Badger 2009)." It is not clear how a six-year study of young children could assess an inherently long-term health effect such as sexual dysfunction. The Agricultural Research Service of the USDA did the study, not a health agency. Agricultural agencies are likely to be more interested than health agencies in promoting the use of soy."
Thus, I was dismayed to see in a recent Pediatrics article (Anders 2012) that some of the same researchers and the same agencies in the same soy-producing state were once again making claims about the quality of soy -based infant formula. Once again they used a short study period to "show" that soy-based formula does little or no harm to children's development.
Assessing the impact of diet on development at one year of age, or even younger, makes little sense. Development refers to changes over time. This recent study's finding that "Breastfed infants have a slight advantage on cognitive development compared with formula-fed infants" (Anders 2012, 1134) should be taken not as a reason for complacency but as a cause for alarm. A slight difference might signal the beginning of a steadily widening gap. Where are the independent long-term studies of the impact of soy-based infant formula on cognitive and other forms of development? The issues remain unresolved (National Toxicology Program 2010).
The American Academy of Pediatrics has given up its 1998 position in support of soy-based formula and now, with few exceptions, recommends that it should not be used, except (a) "for infants with galactosemia and hereditary lactase deficiency (rare) and (b) in situations in which a vegetarian diet is preferred (American Academy of Pediatrics 2008)." However, the recent study in Pediatrics said only that the AAP had placed soy-based formula as third-best, after breastfeeding and cow-milk based formula.
Overall, there seems to be a skew in that study in favor of soy-based formula, at the expense of children and the adults that they will become.
Aloha, George Kent
Department of Political Science University of Hawai'i Honolulu, Hawai'i 96825
REFERENCES
Agricultural Research Service 2004. Study examines long-term health effects of soy infant formula. Agricultural Research 52:2 (January) 8-10. http://www.ars.usda.gov/is/AR/archive/jan04/soy0104.pdf American Academy of Pediatrics 1998. Soy protein-based formulas: recommendations for use in infant feeding. Pediatrics. January 101(1) 148- 153. http://aappolicy.aappublications.org/cgi/reprint/pediatrics;101/1/148.pdf American Academy of Pediatrics 2008. Use of Soy Protein-based formulas in Infant Feeding, Bhatia J, Greer F, and the Committee on Nutrition, Pediatrics. 121;1062-1068. http://pediatrics.aappublications.org/cgi/content/abstract/121/5/1062 Andres, Aline; Mario A. Cleves; Jayne B. Bellando; R. T. Pivik; Patrich H. Casey; and Thomas M. Badger 2012. "Developmental Status of 1-Year-Old Infants Fed Breast Milk, Cow's Milk Formula, or Soy Formula." Pediatrics. Vol. 129, No. 6 (June), 1134-1140. http://pediatrics.aappublications.org/content/129/6/1134.full?sid=ac3d16cf -22a1-4cd2-8687-807e32c3aed9 Badger, Thomas M.; Janet M. Gilchrist; R. Terry Pivik; Aline Andres; Kartik Shankar; Jin-Ran Chen; and Martin J. Ronis. 2009. The health implications of soy infant formula. American Journal of Clinical Nutrition. Vol. 89, No. 5(suppl)1668S-1672S. http://www.ajcn.org/content/89/5/1668S.full Kent, George 2011. Regulating Infant Formula. Amarillo, Texas: Hale Publishing.
National Toxicology Program 2010. Final CERHR Expert Panel Report on Soy Infant Formula. Washington, D.C.: National Institute of Environmental Health Sciences, National Institutes of Health, U.S. Department of Health and Human Services. http://cerhr.niehs.nih.gov/chemicals/genistein- soy/SoyFormulaUpdt/DraftNTPBriefSoyFormula16Mar2010_508.pdf
Conflict of Interest:
None declared