Milk matters: seeding gut ecosystems and shaping microbiota rivalries.

Maternal milk contains its own diverse microbiome, which has been hypothesized to colonize the infant gut during breastfeeding; however, the dynamics of this process are not well understood, particularly among very-low-birth-weight (VLBW) infants. A recent study published in by Shama identifies novel dose-dependent relationships between maternal milk microbiota and infant gut microbiota in a cohort of VLBW infants and further explores the potential impact of infant feeding practices and antibiotic use on these microbial colonization dynamics.

The human milk bacteriome and mycobiome and their inter-kingdom interactions viewed across geography.

Background: The human milk microbiota is one of the biologically active components of human milk, and factors affecting it and the effect size are not well understood. Assessments of human milk microbiota have mainly been done in small cohorts and/or in single geographical locations, and most have been restricted to the bacteriome. Here we assessed the bacterial, archaeal and fungal composition of human milk and the potential inter-kingdom interactions in milk collected from women living in a wide spectrum of countries, environments, and socio-economical settings.

Human milk IgA promotes normal immune development by limiting Th17-inducing in the infant gut.

The gut microbiota is highly dynamic during the first year of life and plays a crucial role in immune development. Breastfeeding is known to support infant health, but the contributions of the numerous breastmilk components to gut microbiota and immune maturation remain unclear. Secretory IgA (SIgA), the most abundant antibody in human milk, is a key modulator of gut microbiota composition.

Protocol: the International Milk Composition (IMiC) Consortium - a harmonized secondary analysis of human milk from four studies.

Introduction: Human milk (HM) contains a multitude of nutritive and nonnutritive bioactive compounds that support infant growth, immunity and development, yet its complex composition remains poorly understood. Integrating diverse scientific disciplines from nutrition and global health to data science, the International Milk Composition (IMiC) Consortium was established to undertake a comprehensive harmonized analysis of HM from low, middle and high-resource settings to inform novel strategies for supporting maternal-child nutrition and health.

Methods And Analysis: IMiC is a collaboration of HM experts, data scientists and four mother-infant health studies, each contributing a subset of participants: Canada (CHILD Cohort,  = 400), Tanzania (ELICIT Trial,  = 200), Pakistan (VITAL-LW Trial,  = 150), and Burkina Faso (MISAME-3 Trial,  = 290).

Public Health Microbiome Curriculum: Looking Below the Tip of the Iceberg for Approaches to Population Health.

We discuss the opportunity for public health microbiome curricula to bridge the gaps in knowledge that exist between microbiome researchers and the lay public. We propose equipping public health professionals, important facilitators of public outreach and behaviour change, with three public health curriculum modules focused on breastfeeding, antibiotics and diet. These modules shift the focus from microbes as pathogens to potential partners in promoting health across the life course.

Human milk as a microbial pacemaker.

A Nature Medicine paper by Sawhney et al. presents a strain-resolved analysis of the gut microbiome from infancy through eight years of age, identifying weaning as an evolutionary trigger for microbial adaptation. Their findings refine the timeline of microbiome development and highlight human milk as a pacemaker of microbial succession.

Clinical translation of microbiome research.

The landscape of clinical microbiome research has dramatically evolved over the past decade. By leveraging in vivo and in vitro experimentation, multiomic approaches and computational biology, we have uncovered mechanisms of action and microbial metrics of association and identified effective ways to modify the microbiome in many diseases and treatment modalities. This Review explores recent advances in the clinical application of microbiome research over the past 5 years, while acknowledging existing barriers and highlighting opportunities.

Gene-by-environment interactions modulate the infant gut microbiota in asthma and atopy.

Background: Gut microbiota has been associated with health and susceptibility to childhood diseases, including asthma and allergies. However, the genomic factors contributing to interindividual variations in gut microbiota remain poorly understood.

Objective: We sought to integrate host genomics with early-life exposures to investigate main and interaction effects on gut microbiota during the first year of life.

Exploring the potential mediating role of systemic antibiotics in the association between early-life lower respiratory tract infections and asthma at age 5 in the CHILD study.

Objective: Lower respiratory tract infections (LRTIs) in early life are one of the strongest risk factors for childhood asthma and are often treated with systemic antibiotics (IV or oral). We aimed to explore the association between early-life LRTIs and systemic antibiotics on asthma development and the potential mediating role of antibiotics in this relationship.

Methods: Data were collected as part of the longitudinal, general Canadian population CHILD Study.

Prenatal vitamin C and fish oil supplement use are associated with human milk microbiota composition in the Canadian CHILD Cohort Study.

Maternal diet may modulate human milk microbiota, but the effects of nutritional supplements are unknown. We examined the associations of prenatal diet and supplement use with milk microbiota composition. Mothers reported prenatal diet intake and supplement use using self-administered food frequency and standardised questionnaires, respectively.

Human milk composition and infant anthropometrics: overview of a systematic review with clinical and research implications.

Background: Despite global public health organizations endorsing breastfeeding or human milk (HM) as the optimal source of nutrition for infants, detailed knowledge of how HM composition influences infant growth is lacking. In this commentary we summarize and interpret the key findings of a large systematic review on HM components and child growth (N = 141 articles included). We highlight the most consistent associations, discuss study quality issues, explore socio-economic and time trends in this body of research, and identify gaps and future research directions.

Antibiotics taken within the first year of life are linked to infant gut microbiome disruption and elevated atopic dermatitis risk.

Background: Atopic dermatitis (AD) is the most common chronic inflammatory skin disease in both pediatric and adult populations. The development of AD has been linked to antibiotic usage, which causes perturbation of the microbiome and has been associated with abnormal immune system function. However, imbalances in the gut microbiome itself associated with antibiotic usage have been inconsistently linked to AD.

The use of prescription medications and non-prescription medications during lactation in a prospective Canadian cohort study.

Background: A lack of safety data on postpartum medication use presents a potential barrier to breastfeeding and may result in infant exposure to medications in breastmilk. The type and extent of medication use by lactating women requires investigation.

Methods: Data were collected from the CHILD Cohort Study which enrolled pregnant women across Canada between 2008 and 2012.

Examining psychosocial pathways to explain the link between breastfeeding practices and child behaviour in a longitudinal cohort.

Objective: Breastfeeding is associated with reduced postpartum depression, stronger parent-child relationships, and fewer behavioral disorders in early childhood. We tested the mediating roles of postpartum depression and parent-child relationship in the association between breastfeeding practices and child behavior.

Study Design: We used standardized questionnaire data from a subset of the CHILD Cohort Study (n = 1,573) to measure postpartum depression at 6 months, 1 year and 2 years, parent-child relationship 1 year and 2 years, and child behavior at 5 years using the Child Behavior Checklist (range 0-100).

Divergent maturational patterns of the infant bacterial and fungal gut microbiome in the first year of life are associated with inter-kingdom community dynamics and infant nutrition.

Background: The gut microbiome undergoes primary ecological succession over the course of early life before achieving ecosystem stability around 3 years of age. These maturational patterns have been well-characterized for bacteria, but limited descriptions exist for other microbiota members, such as fungi. Further, our current understanding of the prevalence of different patterns of bacterial and fungal microbiome maturation and how inter-kingdom dynamics influence early-life microbiome establishment is limited.

Multimodal machine learning for modeling infant head circumference, mothers' milk composition, and their shared environment.

Links between human milk (HM) and infant development are poorly understood and often focus on individual HM components. Here we apply multi-modal predictive machine learning to study HM and head circumference (a proxy for brain development) among 1022 mother-infant dyads of the CHILD Cohort. We integrated HM data (19 oligosaccharides, 28 fatty acids, 3 hormones, 28 chemokines) with maternal and infant demographic, health, dietary and home environment data.

Pre-labor and post-labor cesarean delivery and early childhood adiposity in the Canadian Healthy Infant Longitudinal Development (CHILD) Cohort Study.

Background/objectives: Delivery by cesarean section (CS) compared to vaginal delivery has been associated with increased risk of overweight in childhood. Our study examined if the presence or absence of labor events in CS delivery altered risk of overweight in early childhood (1-5 years) compared to vaginal delivery and if this association differed according to infant sex.

Subjects/methods: The study included 3073 mother-infant pairs from the CHILD Cohort Study in Canada.

Human Milk Macronutrients and Child Growth and Body Composition in the First Two Years: A Systematic Review.

Among exclusively breastfed infants, human milk (HM) provides complete nutrition in the first mo of life and remains an important energy source as long as breastfeeding continues. Consisting of digestible carbohydrates, proteins, and amino acids, as well as fats and fatty acids, macronutrients in human milk have been well studied; however, many aspects related to their relationship to growth in early life are still not well understood. We systematically searched Medline, EMBASE, the Cochrane Library, Scopus, and Web of Science to synthesize evidence published between 1980 and 2022 on HM components and anthropometry through 2 y of age among term-born healthy infants.