A longitudinal observational study of skeletal development between ages 3 months and 6 Years in children fed human milk, milk formula or soy formula

Authors: CHEN, JIN-RAN - University Arkansas For Medical Sciences (UAMS); SAMUEL, HALLIE - Arkansas Children'S Hospital; SHLISKY, JULIE - University Arkansas For Medical Sciences (UAMS); SIMS, CLARK - University Arkansas For Medical Sciences (UAMS); LAZARENKO, OXANA - University Arkansas For Medical Sciences (UAMS); WILLIAMS, D. KEITH - University Arkansas For Medical Sciences (UAMS); ANDRES, ALINE - University Arkansas For Medical Sciences (UAMS); BADGER THOMAS, M - University Arkansas For Medical Sciences (UAMS)

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/3/2023
Publication Date: 6/1/2023
Citation: Chen, J., Samuel, H., Shlisky, J., Sims, C., Lazarenko, O., Williams, D., Andres, A., Badger Thomas, M. 2023. A longitudinal observational study of skeletal development between ages 3 months and 6 Years in children fed human milk, milk formula or soy formula. The American Journal of Clinical Nutrition. 117(6):1211-1218. https://doi.org/10.1016/j.ajcnut.2023.04.002.
DOI: https://doi.org/10.1016/j.ajcnut.2023.04.002

Interpretive Summary: Bone development in babies can be affected by what they are fed, like breast milk, dairy formula, or soy formula. Over 10% of infants in the USA are fed soy formula. Some parts of this formula may affect bone development. Although there are concerns about bone health in those fed soy formula, only a few studies have examined these potential effects. More studies are important so caregivers and physicians can make informed decisions when feeding infants. Our study examined bone development in children fed breast milk, dairy formula, or soy formula from 3 months to 6 years. We found that 6-year-old children that had been fed soy formula had higher bone mineral content than those fed dairy formula. We did not find a difference in bone density for any feeding method. 6-month-old boys fed soy formula had higher levels of bone degradation than boys fed dairy formula. They also had higher levels of bone formation. Overall, we found small differences in children fed soy formula compared to other feeding methods. Follow-up studies as these children age into their teens and beyond can help us find out if early changes in bone development have long term effects on bone health.

Technical Abstract: Background: Early infant feeding can impact skeletal development. Most children are fed breast milk (BF), dairy based infant formula (MF), or soy based infant formula (SF) during the first year of life. The National Health and Nutrition Examination Survey 2003–2010 reports that 12% of U.S. infants consume soy-based infant formula. Despite potential effects of soy-associated isoflavones on skeletal development, studies investigating bone metabolism and structural and functional bone indices in children are lacking. Objective: The objective was to investigate early and persistent effects of SF intake on bone metabolism during the first 6 years of life by comparing infants fed BF, MF, or SF. Design: A total of 433 healthy infants were followed from 3 months to 6 years of age. Children’s skeletal development was assessed using dual-energy X-ray absorptiometry (DXA, N=433) and peripheral quantitative computed tomography (pQCT, N=78). Urinary markers of bone metabolism (N-terminal telopeptide of type I collagen [NTx] and osteocalcin) were evaluated by immunoassays at 6, 24, 60 and 72 months. Results: At 6 years of age, children who consumed SF in infancy have significantly higher BMC measured by DXA compared to the MF group. No differences were seen in BMD between children who were BF, MF or SF using DXA or pQCT. Urinary markers of bone metabolism showed that 6-month-old SF boys have significantly higher levels of NTx compared to MF boys, as well as significantly higher osteocalcin levels compared to BF boys. Conclusions: Though bone metabolism may be more active in infancy when SF is consumed, changes to bone content and density are small, if relevant, to functional bone health. Follow-up studies as children mature into teens and beyond may help elucidate if early bone turnover may have long-term consequences.