Recognized as the gold standard, human milk (HM) is an extremely complex yet fascinating biofluid tailored to meet an infant’s nutritional requirements throughout development. Endocannabinoids and endocannabinoid-like compounds (endocannabinoid metabolome, ECM) are endogenous lipid mediators derived from long-chain polyunsaturated fatty acids that have been identified in HM. Previous research has shown that arachidonoylglycerol might play a role in establishing the infant’s suckling response during lactation by activating the type 1 cannabinoid receptor in the infant’s brain. The mechanisms of action and the role of the ECM in HM are not fully understood. Transitional and mature milk samples were collected from lactating women (n = 24) for ECM characterization, quantification, and to evaluate differences among the two stages. HM samples were analyzed by liquid chromatography-mass spectrometry. Identified members of the ECM were: arachidonoylethanolamine, palmitoylethanolamine, oleoylethanolamine, docosahexaenoylethanolamine, eicoapentaenoylethanolamine, eicosenoylethanolamine, arachidonoylglycerol, palmitoyglycerol, oleoylglycerol, docosahexaenoylglycerol, eicosapentaenoylglycerol, eiconenooylglycerol, arachidonic acid, docosahexaenoic acid, and eicosapentaenoic acid. Only docosahexaenoylglycerol was different across transitional and mature milk (p ≤ 0.05). Data from this cohort suggest that bioactive constituents in HM may also play a role in infant health and development. Future studies can be developed based on this study’s data to help elucidate specific roles for each ECM member in addition to understanding how the ECM modulates infant health.

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Background Recognized as the gold-standard ideal fare, human milk has a unique composition that meets infants’ needs throughout development. Endocannabinoids and endocannabinoid-like compounds [endocannabinoid metabolome (ECM)] are endogenous lipid mediators derived from long-chain polyunsaturated fatty acids. Based on animal models, it has been proposed that endocannabinoid arachidonoyl glycerol (AG) plays a role in establishing the suckling response during lactation. In addition, endocannabinoid ethanolamides have been shown to stimulate food intake. The mechanisms of action and the role of the ECM in human milk are not fully understood. Objectives The present study aimed to characterize and quantify the ECM in human milk samples from an underserved population in Guatemala. Methods Human milk samples were collected from lactating women ( n = 26) for ECM characterization and quantification. Samples were taken at 3 different time points between 4 and 6 mo of lactation during maternal fasting. Human milk samples were analyzed by liquid chromatography-mass spectrometry. Identified members of the ECM were: arachidonoyl ethanolamide, palmitoyl ethanolamide (PEA), oleoyl ethanolamide, docosahexaenoyl ethanolamide, eicoapentaenoyl ethanolamide, eicosenoyl ethanolamide, AG, palmitoyl glycerol, oleoyl glycerol, docosahexaenoyl glycerol, eicosapentaenoyl glycerol, eicosenoyl glycerol, arachidonic acid (ARA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). Results Overall, concentrations in the ethanolamide group were lower than the glycerols. A time effect was observed for ARA, DHA, EPA, and PEA across the 3 time points ( P ≤ 0.05). Conclusions Our study identified the ECM in mature human milk and provides the first report for a population with health disparities within a developing country. The few studies available have been conducted in developed countries. Hypotheses for future studies can be developed based on this study's data to help elucidate specific roles for members of the ECM and how this biological system modulates infant health and development.

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Background Dietary long-chain polyunsaturated fatty acids are known to benefit infant development. After birth, human milk provides arachidonic, eicosapentaenoic, and docosahexaenoic acids to the infant. Endocannabinoids are endogenous lipid mediators derived from the long-chain polyunsaturated fatty acids. Although the roles and the mechanisms of action are not fully understood, previous researchers have suggested that endocannabinoids might play a role in infant feeding behavior. Research Aims To assess (i) maternal dietary intake of long-chain polyunsaturated fatty acids and (ii) their relationship to concentrations of fatty acids and derived endocannabinoids in human milk. Methods For this exploratory-longitudinal study, participants ( N = 24) provided dietary intake data and milk samples. Fatty acids and derived endocannabinoids: Arachidonylethanolamide, arachidonoylglycerol, docosahexaenoyl glycerol, eicosapentaenoyl ethanolamide, and eicosapenaenoyl glycerol were identified in their milk by liquid chromatography-mass spectrometry and correlations to dietary fatty acids were assessed. Results Participants were not consuming recommended amounts of docosahexaenoic acid. Significant correlations ( p ≤ .05) were only found between dietary docosahexaenoic and eicosapentaenoic acids and the concentrations of these in human milk. Moreover, only dietary docosahexaenoic acid was correlated ( p = .031) with its corresponding endocannabinoid, docosahexaenoyl glycerol. Conclusions To the best of our knowledge, this may be one of the first studies evaluating relationships between dietary long-chain polyunsaturated fatty acids and multiple endocannabinoids in human milk. Our findings suggest that endocannabinoid concentrations could be modulated by dietary precursors. Future research studies can be designed based on these data to better elucidate the roles of endocannabinoids in human milk for infant health and development.