Early nutrition critically influences growth, neurodevelopment and morbidity among infants born of very low birth weight (VLBW), but current one-size-fits-all feeding regimes do not optimally support these vulnerable infants. There is increasing interest in precision nutrition approaches, but it is unclear which Human Milk (HM) components require personalized adjustment of doses. Previous efforts have focused on macronutrients, but HM also contains essential micronutrients as well as non-nutrient bioactive components that shape the gut microbiome. Further, it is unclear if or how parental factors (e.g. body mass index, diet) and infant factors (e.g. genetics, gut microbiota, sex, acuity) influence relationships between early nutrition and growth, neurodevelopment and morbidity. Understanding these complex relationships is paramount to developing effective personalized HM feeding strategies for VLBW infants. This is the overarching goal of the proposed Optimizing Nutrition and Milk (Opti-NuM) Project. The Opti-NuM Project brings together two established research platforms with complementary expertise and resources: 1) the MaxiMoM Program\* with its clinically embedded translational neonatal feeding trial network in Toronto (Dr. Deborah O'Connor, Dr. Sharon Unger) and 2) the International Milk Composition (IMiC) Consortium, a world-renowned multidisciplinary network of HM researchers and data scientists collaborating to understand how the myriad of HM components contribute as a whole to infant growth and development, using systems biology and machine learning approaches. Members of the IMiC Corsortium that will work with on this study are located at the University of Manitoba (Dr. Meghan Azad), University of California (Dr. Lars Bode) and Stanford (Dr. Nima Aghaeepour).