Some new studies and a review article:
Title: Evaluation of macronutrient content of fresh and frozen human milk over 6 months.
In: The Journal of Maternal-Fetal & Neonatal Medicine 2019 Aug 8:1-8. doi: 10.1080/14767058.2019.1651269. [Epub ahead of print].
Authors: Tanriverdi S, Koroglu O, Uygur Ö, Yalaz M, Kultursay N.
Abstract: "Aim: In this study, we aimed to see the time-dependent changes in the macronutrient content of early frozen breast milk and also to compare it with fresh breast milk in the first 6 months. Materials and method: We evaluated the milk samples of 43 mothers who delivered at term. Milk samples after the first 15 days following delivery were expressed and collected dividing into seven aliquots to be stored frozen at -20 °C. Every month freshly collected new milk samples were analyzed together with one aliquot of the stored samples, up to 6 months. The energy, protein, lipid, and carbohydrate contents of samples were analyzed by Miris Human Milk Analyzer. Results: In the first 3 months, fresh milk had higher caloric and lipid content when compared to frozen samples. The protein content of fresh milk decreased after 2 months and became lower than frozen samples. The energy and lipid content of frozen milk decreased over time but protein and carbohydrate contents stayed stable. Carbohydrate content of fresh and frozen samples did not show major changes. Conclusion: It may be more suitable to consume the frozen milk that was collected in the early weeks of delivery within first 2 months."
Abstract only: https://www.tandfonline.com/doi/abs/10.1080/14767058.2019.1651269?journalCode=ijmf20
Title: Determinants of persistent organic pollutant (POP) concentrations in human breast milk of a cross-sectional sample of primiparous mothers in Belgium.
In: Environment International 2019 Aug 3;131:104979. doi: 10.1016/j.envint.2019.104979. [Epub ahead of print]
Authors: Aerts R, Van Overmeire I, Colles A, Andjelković M, Malarvannan G, Poma G, Den Hond E, Van de Mieroop E, Dewolf MC, Charlet F, Van Nieuwenhuyse A, Van Loco J, Covaci A.
Abstract: "BACKGROUND: Bio-accumulation of persistent organic pollutants (POPs) in the environment and in the food chain can lead to high pollutant concentrations in human fat-containing tissues and breast milk. OBJECTIVES: We aimed to identify the maternal characteristics that determined POP concentrations in breast milk of primiparous mothers in Belgium. METHODS: Breast milk samples were obtained from a cross-sectional sample of 206 primiparous mothers in 2014. POP concentrations in breast milk samples were determined by GC-ECNI-MS and GC-EI-MS/MS depending on the analytes' sensitivity. Associations between POP concentrations in breast milk and potential determinants were investigated using two-way contingency tables and multivariable generalized linear models. RESULTS: Fifteen of the 23 screened POPs were detected in the breast milk samples. Four organochlorine compounds (p,p'-DDT, p,p'-DDE, HCB and β-HCH) and two brominated flame retardant congeners (BDE-47, BDE-153) were detected at concentrations above the limit of quantification in >50% of the breast milk samples. Maternal age and BMI were usually associated with higher POP concentrations. Rural residency and consumption of home-produced eggs, fatty fish and fish oil supplements were associated with higher concentrations of DDT and DDE. Consumption of fatty fish and being breastfed during childhood were associated with higher concentrations of HCB and β-HCH. Fish oil supplements and home-produced eggs were associated with higher concentrations of BDEs, but for BDE congeners exposure routes other than diet require further investigation. CONCLUSIONS: Dietary and non-dietary determinants predict individual POP concentrations in breast milk."
Open access: https://www.sciencedirect.com/science/article/pii/S0160412019309080?via%3Dihub
Title: In Vitro Digestion of Human Milk: Influence of the Lactation Stage on the Micellar Carotenoids Content.
In: Antioxidants 2019, 8(8), 291; https://doi.org/10.3390/antiox8080291.
Authors: Ana A. O. Xavier, Juan E. Garrido-López, Josefa Aguayo-Maldonado, Juan Garrido-Fernández, Javier Fontecha, Antonio Pérez-Gálvez.
Abstract: "Human milk is a complex fluid with nutritive and non-nutritive functions specifically structured to cover the needs of the newborn. The present study started with the study of carotenoid composition during progress of lactation (colostrum, collected at 3-5 d postpartum; mature milk, collected at 30 d postpartum) with samples donated from full-term lactating mothers (women with no chronic diseases, nonsmokers on a regular diet without supplements, n = 30). Subsequently, we applied an in vitro protocol to determine the micellarization efficiency of the carotenoids, which were separated by HPLC and quantified by the external standard method. That in vitro protocol is tailored for the biochemistry of the digestive tract of a newborn. To the best of our knowledge, the present study is the first report of carotenoids micellar contents, obtained in vitro. This study reveals, from the in vitro perspective, that colostrum and mature milk produce significant micellar contents of carotenoids despite lipids in milk are within highly complex structures. Indeed, the lactation period develops some influence on the micellarization efficiency, influence that might be attributed to the dynamics of the milk fat globule membrane (MFGM) during the progress of lactation."
Open access: https://www.mdpi.com/2076-3921/8/8/291
Title: The Functional Power of the Human Milk Proteome. [Review article]
In: Nutrients 2019 Aug 8;11(8). pii: E1834. doi: 10.3390/nu11081834.
Authors: Zhu J, Dingess KA.
Abstract: "Human milk is the most complete and ideal form of nutrition for the developing infant. The composition of human milk consistently changes throughout lactation to meet the changing functional needs of the infant. The human milk proteome is an essential milk component consisting of proteins, including enzymes/proteases, glycoproteins, and endogenous peptides. These compounds may contribute to the healthy development in a synergistic way by affecting growth, maturation of the immune system, from innate to adaptive immunity, and the gut. A comprehensive overview of the human milk proteome, covering all of its components, is lacking, even though numerous analyses of human milk proteins have been reported. Such data could substantially aid in our understanding of the functionality of each constituent of the proteome. This review will highlight each of the aforementioned components of human milk and emphasize the functionality of the proteome throughout lactation, including nutrient delivery and enhanced bioavailability of nutrients for growth, cognitive development, immune defense, and gut maturation."
Open access: https://www.mdpi.com/2072-6643/11/8/1834/htm