The study of human milk composition
Authors:   ,   Latvia University of Life Sciences and Technologies, Aumeistere Liva 
Published: August 2021

The Ph.D. thesis was elaborated during the period from November 2016 to March 2021 at the Faculty of Food Technology of the Latvia University of Life Sciences and Technologies and the Laboratory of Chemistry of the Institute of Food Safety, Animal Health and Environment BIOR. The hypothesis of the Ph.D. thesis: maternal nutrition during lactation predicts human milk composition and serves as a basis for providing the essential nutrients for the infant. The hypothesis is supported by the following thesis: • a lactating woman can meet her nutritional needs by consuming a well-balanced diverse diet, which also serves as the basis for providing certain nutrients for infant via human milk; • total fat, protein, lactose content in human milk is not directly affected by maternal diet; • qualitative and quantitative fatty acid composition of human milk is influenced by maternal dietary habits during lactation; • essential and potentially toxic element content in human milk is related to maternal dietary habits during lactation; • exclusively breastfed infants till six months of age can receive a sufficient amount of energy and nutrients (fat, protein, lactose, fatty acids and essential elements) via human milk. The research object of the Ph.D. thesis: mature human milk (at least 28 days postpartum). The aim of the Ph.D. thesis: to evaluate human milk composition in relation to maternal nutrition and to assess nutritional supply for exclusively breastfed infants. Consequential research objectives were set to achieve the aim of the Ph.D. thesis: 1) to analyse protein, lactose, fat, fatty acid, essential (Ca, Mg, Na, K, Zn, Se, Mn, Fe, Cu, Co, Cr) and potentially toxic element (Al, Ni, As, Sr, Cd, Sn, Sb, Pb) content in human milk; 2) to evaluate the compliance of the women’s nutrition during lactation with the recommendations at the national and European level; 3) evaluate the association between maternal nutrition and human milk composition; 4) based on elaborated human milk composition results, theoretically evaluate nutritional adequacy of exclusively breastfed infants till six months of age. The Ph.D. thesis consists of three chapters: Chapter 1. Overview of the literature. Description of human milk and its composition influencing factors, including maternal nutrition; Chapter 2. Recital of materials, methods, and statistical analysis methods used in the study; Chapter 3. Summary of elaborated results regarding human milk composition and maternal dietary habits during lactation. Assessment of human milk composition in relation to maternal nutrition. Theoretical evaluation of the nutritional adequacy of exclusively breastfed infants (one to six months old). At the end of the Ph.D. thesis, conclusions of the study are compiled, and suggestions for future research are stated. The scientific significance of the Ph.D. thesis: 1) for the first time in Latvia, composition of human milk has been comprehensively analysed; 2) elaborated data serve as a contribution from Latvia to the global research area of human milk composition. The national significance of the Ph.D. thesis: 1) elaborated findings can be used to develop nutritional guidance for lactating women in Latvia; 2) compiled results can be used to develop nutrient intake guidelines for infants in Latvia (≤6 months old). The study has been financially supported by the grants: • Strengthening Research Capacity in the Latvia University of Life Sciences and Technologies. Project “The study of human milk composition”. Project No. Z2. Contract No. 3.2.-10/44. Project status – finished (project time from 1 January 2017 to 31 December 2018); • Conducting Fundamental Research in the Latvia University of Life Sciences and Technologies. Project “Natural variations in fatty acid composition of human milk”. Project No. G1. Contract No. 3.2-10/2019/LLU. Project status – ongoing (project time from 6 January 2020 to 5 January 2022); • Latvia University of Life Sciences and Technologies Transition to the New Doctoral Funding Model. European Social Fund Project No. 8.2.2.0/20/I/001. Project status – ongoing (project time from 17 May 2021 to 16 May 2022). The Ph.D. thesis is written in English on 127 pages and contains 34 tables, 15 figures, and 19 annexes. In total, 188 information sources were used in the study.