Exploring the association between human breast milk lipids and early adiposity rebound in children: A case-control study

Objectives: Adiposity rebound (AR) corresponds to the start of the second rise in the body mass index curve during infant growth. Early AR (before age 5) confers increased risk of adiposity and metabolic disorders but is less likely to occur in breastfed infants. Although lipids in breast milk are important in child growth, information is limited regarding which lipids are involved in AR. The object of this study was to explore the association between breast milk lipids and AR status in children. Methods: We designed a case-control study of 184 mother–child pairs (AR cases: n = 93; controls: n = 91) included from the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study. Breast milk was collected 1 month postpartum and comprehensive lipid analysis was performed. Partial least square-discriminant analysis was used to explore candidate lipids, and multivariable logistic regression analysis was used to evaluate associations with the AR status of children. Results: We detected 667 lipid molecules in 12 lipid classes in breast milk. Partial least square-discriminant analysis revealed the association of fatty acid-hydroxy fatty acid (FAHFA) and cholesterol ester (ChE) with AR status. Multivariable logistic regression analysis showed that in pairs with exclusive breastfeeding at 1 month postpartum, FAHFA (odds ratio 1.57 [95% confidence interval, 1.06–2.32]) was positively associated with early AR, and ChE (odds ratio 0.55 [95% confidence interval, 0.36–0.86]) was negatively associated. Conclusions: Breast milk lipids (FAHFA, ChE) associated with the AR status of children, indicating the potential to regulate a child's adiposity and possible metabolic disorders in adulthood.