Xian Cohort Study: An Association of Breast Milk Composition with Maternal BMI And Infant Growth During the First Three Months of Life

The aim of this study was to establish a mother and child cohort in the Chinese population and to investigate human milk (HM) composition and its relationship with infant growth and development during the first three months of life.

110 Chinese mother and infant pairs were included in this prospective cohort. Changes of total energy, total fat, total protein, true protein, carbohydrate and osteopontin (OPN) in milk of Chinese mothers at one (T1), two (T2), three (T3) months lactation were analyzed. HM fatty acid (FA) profiles were measured by GC and HM proteomic profiling was conducted by matrix-assisted laser desorption ionization (MALDI), time-of-flight (TOF) mass spectrometry (MS). BMI of the mothers and infant growth indicators, such as weight, length, BMI and head circumference were also recorded at three time points.

Total energy, total fat, total protein, true protein and OPN levels significantly decreased during the first three month of lactation (P < 0.05). Similarly, medium and long-chain saturated FA, including C13:0, C16:0, C20:0, C22:0 and C24:0, and n-6 polyunsaturated (PU) FA including C20:3n6 and C20:4n6, and n-3 PUFA, including C18:3n3, C20:3n3 and n6/n3 ration all significantly decreased over time (P < 0.05). Conversely, short-chain fatty acids, such as butyrate and C6:0, increased during the first three months (P <0.05). HM proteomic analyses distinguished protein composition over time (P = 0.001). Personalized analyses demonstrated that the HM of high-BMI (BMI>25) mothers presented increased total fat, total protein and total energy at T1 and/or T3, and increased OPN at T3 when compared with the normal-BMI (18<BMI<20) mothers (p < 0.05). Similarly, the content of n6 PUFA including C18:3n6 at T1, C20:3n6 at T1-T3 and n6/n3 ratio at T3 were significantly higher in high-BMI mother’s milk. However, the content of MUFA, mainly C18:1 was significantly higher in low-BMI mother’s milk. In addition, BMI of the mothers was positively correlated with the specific FA C20:3n6 (P <0.05,r = 0.27, 0.34, 0.36 respectively) as well as the head circumference (HC) of infants (P <0.05,r = 0.31, 0.33, 0.20 respectively) over the three time points.

This study showed that HM changes over time and many of the studied components decreased in concentration during the first three months of lactation. It also concluded that maternal postpartum BMI can influence the FA profile of HM and HC of the infants. This study provides more evidence to the Chinese breast-milk database and further knowledge of HM FA function to support future strategies for the health growth and development of Chinese infants.

H&H Group Global Research and Technology Center, Guangzhou, China; School of Food Science, South China Agriculture University; Division of Laboratory Medicine, Zhujiang Hospital, Southern Medical University; Child Health Care Center, Changsha Hospital for Maternal and Child Care, Changsha, China