Soy-based infant formula enhances bone metabolism compared to breast feeding and dairy-based infant formula

U.S.A: A new study revealed that soy-formula-fed infants have better and improved bone metabolism than breastfed and dairy-based formula infants as per the urinary biomarkers detected at 6 years of age. There were no significant differences between bone metabolism or bone mineral density between the ages of 2 and 6 years. The study results were published in The American Journal of Clinical Nutrition. 

Skeletal development may be affected by early newborn nutrition. During their first year of life, the majority of babies are fed breast milk (BF), dairy (MF) - or soy-based (SF) baby formula. According to the National Health and Nutrition Examination Survey 2003–2010, 12% of babies in the United States drink baby formula made with soy. Studies examining the metabolism of bone and morphological and functional bone indices in children are sparse, despite the possibility that soy-associated isoflavones may have an impact on skeletal development. Hence researchers conducted a study to investigate the early effects of SF intake on bone metabolism and structure during the first 6 years of life by comparing infants fed BF, MF, or SF. 

From 3 months to 6 years old, 433 healthy babies were monitored. Dual-energy X-ray absorptiometry (DXA, N=433) and peripheral quantitative computed tomography (pQCT, N=78) were used to evaluate the skeletal growth of children. N-terminal telopeptide of type I collagen [NTx] and osteocalcin, urinary indicators of bone metabolism, were assessed by immunoassays at 6, 24, 60, and 72 months.

Key findings: 

• There were no statistically significant group differences in BMD between children who were BF, MF, or SF using DXA or pQCT.
• Children who consumed SF in infancy had significantly greater whole-body BMC measured by DXA compared to the MF group when observed at 6 years of age. 
• When compared to MF boys and BF boys, six-month-old SF boys showed considerably higher levels of NTx and osteocalcin, respectively. 

Thus, the trial showed how soy-fed infants had an edge over diary fed and breast-fed infants in enhanced bone metabolism. 

Further reading: 

Chen JR, Samuel HA, Shlisky J, et al. A Longitudinal Observational Study of Skeletal Development Between Ages 3 Months and 6 Years in Children Fed Human Milk, Milk Formula or Soy Formula [published online ahead of print, 2023 Apr 5]. Am J Clin Nutr. 2023;S0002-9165(23)46321-6. doi: 10.1016/j.ajcnut.2023.04.002