Determinants of colostrum and breast milk immune composition and consequences for infant health

Background: Breast milk is the principal source of nutrition during a critical period of immune programming - maternal and environmental exposures may influence breast milk composition and infant health. Objectives: To examine whether environmental and/or maternal factors influence levels of immune active components in colostrum and breast milk and identify associations between these factors and health outcomes. To examine if colostrum/breast milk immune composition can be grouped into specific 'lactotypes'. Methods: A prospective cohort study of mother/infant pairs in London, Moscow and Verona. Colostrum samples (days 0-6) and Mature Breast Milk (4-6 weeks) were analysed in duplicate using electrochemiluminescence, and the relationship between levels of immune active factors and maternal/environmental/infant factors was evaluated using mixed models. Lactotypes were identified using Principal Components Analysis. Results: Levels of immune active cytokines and growth factors in colostrum declined rapidly over time (r=-0.39 to -0.16; p