Doctor of Philosophy (PhD)


School of Nutrition and Food Sciences

Document Type



Human breast milk (HBM) is an extremely complex yet fascinating biofluid tailored to meet an infant’s nutritional requirements for development. Amongst the nutrients present in HBM, the long-chain polyunsaturated fatty acids (LCPUFAs) are of high importance due to the pivotal role they play in infant cognitive and visual development, and growth. In addition, the LCPUFAs are precursors to endocannabinoids (EC) which are endogenous lipid mediators. EC exert metabolic responses including appetite and food intake regulation, and they have been identified to play a role in establishing the suckling response of the newborn that is needed to nurse. Thus, we aimed to characterize and quantify the EC present in HBM, termed the EC metabolome (ECM). HBM samples were collected from two different populations, one in Guatemala (n = 26) and the other one in the United States (n = 24). We collected HBM at different lactation stages: transitional (2 weeks postpartum) and mature (4 weeks and 16-24 weeks postpartum) milk. Using liquid chromatography-mass spectrometry analyses, we identified 15 members of the ECM in both lactation stages: arachidonoylethanolamine, palmitoylethanolamine, oleoylethanolamine, docosahexaenoylethanolamine, eicoapentaenoylethanolamine, eicosenoylethanolamine, arachidonoylglycerol, palmitoyglycerol, oleoylglycerol, docosahexaenoylglycerol, eicosapentaenoylglycerol, eiconenooylglycerol, arachidonic acid, docosahexaenoic acid, and eicosapentaenoic acid. Overall, members in the glycerol group were higher in concentration than those of the ethanolamide group. To date, the mechanisms of action and the role of the ECM in HBM and infant development are not fully understood. Data from the present study provides a foundation to develop future studies to help elucidate how the ECM modulates infant health and development.



Committee Chair

Lammi-Keefe, Carol