 The results of this study suggest that breast milk contains high levels of tryptophan, TRP, which is important for infant neurodevelopment. However, the levels of free TRP are lower in pre-term breast milk than in-term breast milk. Additionally, the levels of TRP metabolites such as chineurinine, KYN, and chineurinic acid, Keener, increase over time in term breast milk, while they remain unchanged in pre-term breast milk. Furthermore, the study found that the levels of pro-inflammatory cytokines such as tumor necrosis factor alpha, TNF, interleukin-6, Illinois-6, and interleukin-8, Illinois-8, are higher in both term and pre-term breast milk at day 7 postpartum when compared to day 14 postpartum. These findings suggest that the presence of TRP and its metabolites in breast milk may be associated with the neurological development of exclusively breastfed pre-term infants. This article was authored by Louisa Rourke, Gerard Clark, Eva Nolan, and others.