Potential interaction between timing of infant complementary feeding and breastfeeding duration in determination of early childhood gut microbiota composition and BMI

Understanding risk and causal mechanisms for developing obesity in infants and young children: A National Institutes of Health workshop

Obesity in children remains a major public health problem, with the current prevalence in youth ages 2-19 years estimated to be 19.7%. Despite progress in identifying risk factors, current models do not accurately predict development of obesity in early childhood. There is also substantial individual variability in response to a given intervention that is not well understood. On April 29-30, 2021, the National Institutes of Health convened a virtual workshop on "Understanding Risk and Causal Mechanisms for Developing Obesity in Infants and Young Children." The workshop brought together scientists from diverse disciplines to discuss (1) what is known regarding epidemiology and underlying biological and behavioral mechanisms for rapid weight gain and development of obesity and (2) what new approaches can improve risk prediction and gain novel insights into causes of obesity in early life. Participants identified gaps and opportunities for future research to advance understanding of risk and underlying mechanisms for development of obesity in early life. It was emphasized that future studies will require multi-disciplinary efforts across basic, behavioral, and clinical sciences. An exposome framework is needed to elucidate how behavioral, biological, and environmental risk factors interact. Use of novel statistical methods may provide greater insights into causal mechanisms.

The Role of Diet and Nutritional Interventions for the Infant Gut Microbiome

The infant gut microbiome plays a key role in the healthy development of the human organism and appears to be influenced by dietary practices through multiple pathways. First, maternal diet during pregnancy and infant nutrition significantly influence the infant gut microbiota. Moreover, breastfeeding fosters the proliferation of beneficial bacteria, while formula feeding increases microbial diversity. The timing of introducing solid foods also influences gut microbiota composition. In preterm infants the gut microbiota development is influenced by multiple factors, including the time since birth and the intake of breast milk, and interventions such as probiotics and prebiotics supplementation show promising results in reducing morbidity and mortality in this population. These findings underscore the need for future research to understand the long-term health impacts of these interventions and for further strategies to enrich the gut microbiome of formula-fed and preterm infants.

Metagenomic Characterisation of the Gut Microbiome and Effect of Complementary Feeding on Bifidobacterium spp. in Australian Infants

Complementary feeding induces dramatic ecological shifts in the infant gut microbiota toward more diverse compositions and functional metabolic capacities, with potential implications for immune and metabolic health. The aim of this study was to examine whether the age at which solid foods are introduced differentially affects the microbiota in predominantly breastfed infants compared with predominantly formula-fed infants. We performed whole-genome shotgun metagenomic sequencing of infant stool samples from a cohort of six-month-old Australian infants enrolled in a nested study within the ORIGINS Project longitudinal birth cohort. Infants born preterm or those who had been administered antibiotics since birth were excluded. The taxonomic composition was highly variable among individuals at this age. Predominantly formula-fed infants exhibited a higher microbiome diversity than predominantly breastfed infants. Among the predominantly breastfed infants, the introduction of solid foods prior to five months of age was associated with higher alpha diversity than solid food introduction after six months of age, primarily due to the loss of Bifidobacterium infantis. In contrast, the age at which solid food was introduced was not associated with the overall change in diversity among predominantly formula-fed infants but was associated with compositional changes in Escherichia abundance. Examining the functional capacity of the microbiota in relation to these changes, we found that the introduction of solid foods after six months of age was associated with elevated one-carbon compound metabolic pathways in both breastfed and formula-fed infants, although the specific metabolic sub-pathways differed, likely reflecting different taxonomic compositions. Our findings suggest that the age of commencement of solid foods influences the gut microbiota composition differently in predominantly breastfed infants than in predominantly formula-fed infants.

Optimal timing of introduction of complementary feeding: a systematic review and meta-analysis

CONTEXT

The timing of introducing complementary feeding (CF) is crucial because premature or delayed CF can be associated with adverse health outcomes in childhood and adulthood.

OBJECTIVE

This systematic review aims to evaluate the impact of the timing of CF introduction on health, nutrition, and developmental outcomes among normal-term infants.

DATA SOURCES

Electronic databases and trial registries were searched, along with the reference lists of the included studies and relevant systematic reviews.

DATA EXTRACTION

Two investigators independently extracted data from the included studies on a standardized data-extraction form.

DATA ANALYSIS

Data were meta-analyzed separately for randomized controlled trials (RCTs) and observational studies on the basis of early introduction of CF (< 3 months, < 4 months, < 6 months of age) or late introduction of CF (> 6 months, > 8 months of age). Evidence was summarized according to GRADE criteria. In total, 268 documents were included in the review, of which 7 were RCTs (from 24 articles) and 217 were observational studies (from 244 articles). Evidence from RCTs did not suggest an impact of early introduction, while low-certainty evidence from observational studies suggested that early introduction of CF (< 6 months) might increase body mass index (BMI) z score and overweight/obesity. Early introduction at < 3 months might increase BMI and odds of lower respiratory tract infection (LRTI), and early introduction at < 4 months might increase height, LRTI, and systolic and diastolic blood pressure (BP). For late introduction of CF, there was a lack of evidence from RCTs, but low-certainty evidence from observational studies suggests that late introduction of CF (> 6 months) might decrease height, BMI, and systolic and diastolic BP and might increase odds of intestinal helminth infection, while late introduction of CF (> 8 months) might increase height-for-age z score.

CONCLUSION

Insufficient evidence does suggest increased adiposity with early introduction of CF. Hence, the current recommendation of introduction of CF should stand, though more robust studies, especially from low- and middle-income settings, are needed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42020218517.

Prebiotics in New-Born and Children's Health

At present, prebiotics, like probiotics, are receiving more attention as a promising tool for health maintenance. Many studies have recognized the role of prebiotics in preventing and treating various illnesses including metabolic disorders, gastrointestinal disorders, and allergies. Naturally, prebiotics are introduced to the human body in the first few hours of life as the mother breastfeeds the newborn. Prebiotic human milk oligosaccharides (HMOs) are the third largest constituent of human breastmilk. Studies have proven that HMOs modulate an infant's microbial composition and assist in the development of the immune system. Due to some health conditions of the mother or beyond the recommended age for breastfeeding, infants are fed with formula. Few types of prebiotics have been incorporated into formula to yield similar beneficial impacts similar to breastfeeding. Synthetic HMOs have successfully mimicked the bifidogenic effects of breastmilk. However, studies on the effectiveness and safety of consumption of these synthetic HMOs are highly needed before massive commercial production. With the introduction of solid foods after breastfeeding or formula feeding, children are exposed to a range of prebiotics that contribute to further shaping and maturing their gut microbiomes and gastrointestinal function. Therefore, this review evaluates the functional role of prebiotic interventions in improving microbial compositions, allergies, and functional gastrointestinal disorders in children.

Pre-pregnancy body mass index and gut microbiota of mothers and children 5 years postpartum

BACKGROUND

Maternal pre-pregnancy body mass index (BMI) has been linked to altered gut microbiota in women shortly after delivery and in their offspring in the first few years of life. But little is known about how long these differences persist.

METHODS

We followed 180 mothers and children from pregnancy until 5-year postpartum in the Gen3G cohort (Canada, enrolled 2010-2013). At 5 years postpartum we collected stool samples from mothers and children and estimated the gut microbiota by 16 S rRNA sequencing (V4 region) using Illumina MiSeq, and assigning amplicon sequence variants (ASV). We examined whether overall microbiota composition (as measured by microbiota β diversity) was more similar between mother-child pairs compared to between mothers or between children. We also assessed whether mother-child pair sharing of overall microbiota composition differed by the weight status of mothers before pregnancy and of children at 5-year. Furthermore, in mothers, we examined whether pre-pregnancy BMI, BMI 5-year postpartum, and change in BMI between time points was associated with maternal gut microbiota 5-year postpartum. In children, we further examined associations of maternal pre-pregnancy BMI and child 5-year BMI z-score with child 5-year gut microbiota.

RESULTS

Mother-child pairs had greater similarity in overall microbiome composition compared to between mothers and between children. In mothers, higher pre-pregnancy BMI and 5-year postpartum BMI were associated with lower microbiota observed ASV richness and Chao 1 index; in children's gut microbiota, higher maternal pre-pregnancy BMI was weakly associated with lower microbiota Shannon index, whereas child's 5-year BMI z-score was associated with higher observed ASV richness. Pre-pregnancy BMI was also linked to differential abundances of several microbial ASVs in the Ruminococcaceae and Lachnospiraceae families, but no specific ASV had overlapping associations with BMI measures in both mothers and children.

CONCLUSIONS

Pre-pregnancy BMI was associated with gut microbiota diversity and composition of mothers and children 5 years after birth, however, the nature and direction of most associations differed for mothers and children. Future studies are encouraged to confirm our findings and look into potential mechanisms or factors that may drive these associations.

Maternal breastfeeding is associated with offspring microbiome diversity; a secondary analysis of the MicrobeMom randomized control trial

Background

Microbial dysbiosis in infancy can influence long-term health outcomes such as childhood obesity. The aim of this study is to explore relationships among maternal well-being during pregnancy, breastfeeding, and the infant gut microbiome.

Methods

This is a secondary analysis of healthy pregnant women from the MicrobeMom study, a double-blind randomized control trial of maternal probiotic supplementation (Bifidobacterium breve 702258) versus placebo antenatally and up to 3 months postpartum. Maternal well-being was assessed using the WHO-5 well-being index at 16 weeks' and 34 weeks' gestation. Breastfeeding practices were recorded at discharge from hospital and at 1 month postpartum. Infant stool samples were obtained at 1 month of age. Next generation shotgun sequencing determined infant microbial diversity. Independent sample t-tests and Mann-Whitney U tests informed adjusted regression analysis, which was adjusted for delivery mode, antibiotics during delivery, maternal age and body mass index (BMI), and probiotic vs. control study group.

Results

Women (n = 118) with at least one measure of well-being were on average 33 years (SD 3.93) of age and 25.09 kg/m2 (SD 3.28) BMI. Exclusive breastfeeding was initiated by 65% (n = 74). Any breastfeeding was continued by 69% (n = 81) after 1 month. In early and late pregnancy, 87% (n = 97/111) and 94% (n = 107/114) had high well-being scores. Well-being was not associated with infant microbial diversity at 1 month. In adjusted analysis, exclusive breastfeeding at discharge from hospital was associated with infant microbial beta diversity (PC2; 0.254, 95% CI 0.006, 0.038). At 1 month postpartum, any breastfeeding was associated with infant microbial alpha diversity (Shannon index; -0.241, 95% CI -0.498, -0.060) and observed species; (-0.325, 95% CI -0.307, -0.060), and infant microbial beta diversity (PC2; 0.319, 95% CI 0.013, 0.045). Exclusive breastfeeding at 1 month postpartum was associated with infant alpha diversity (Shannon index -0.364, 95% CI -0.573, -0.194; Simpson index 0.339, 95% CI 0.027, 0.091), and infant's number of observed microbial species (-0.271, 95% CI -0.172, -0.037).

Conclusion

Breastfeeding practices at 1 month postpartum were associated with lower microbial diversity and observed species in infants at 1 month postpartum, which is potentially beneficial to allow greater abundance of Bifidobacterium.

Clinical trial registration

ISRCTN53023014.

Are Complementary Feeding Practices Aligned with Current Recommendations? A Narrative Review

The complementary feeding introduction period (introduction of solid foods alongside breastmilk or formula) is defining in children's health; however, it appears that many parents do not follow complementary feeding guidelines. Our aim was to describe current parental feeding practices during complementary feeding in relation to current recommendations and explore determinants of adherence to guidelines. We included any relevant studies published within the last decade in French or English and summarized findings by recommendation category. The timing of complementary food introduction varied widely across and within continents (earlier in North America and often delayed in Asia). The introduction of allergenic foods tended to be delayed globally. Although some parents now begin complementary feeding with solid foods (i.e., baby-led weaning), delayed introduction of lumpy textures was still prevalent in the United States and in Europe. The consumption of iron-rich foods was predominantly low in Africa. Added sugars were globally introduced early, especially in America. Evidence for the prevalence of responsive feeding practices among parents is unclear due to the small number of studies. Determinants of complementary feeding practices included parental characteristics, such as age, education, socio-economic status, and race/ethnicity. Interventions aiming to increase adherence to complementary feeding guidelines must account for parental characteristics.

Associations between early introduction to complementary foods, subsequent cereal-added bottle feeding and daily macronutrient intake among infants

Introducing complementary foods early during infancy has been associated with an increased risk of overweight later in life, but the pathway is an understudied topic. Hence the study was conducted with low-income and primarily minority mother-infant dyads to: 1) understand how the introduction of complementary foods prior to 4 months was associated with socio-demographic characteristics and food security status; 2) determine the association between early introduction to complementary foods and breastfeeding and adding cereal into the bottle in later infancy (i.e., at 6 and 9 months), and; 3) examine how adding infant cereal into the bottle was related to daily calorie and macronutrient intake in infancy. We conducted interviews with mothers (n = 201) at 4 months of age and 24-h feeding recalls at age 6 and 9 months. Results indicated that 29% of the infants were fed complementary foods before 4 months of age. Introducing complementary foods early was negatively associated with breastfeeding and positively associated with adding cereal into the bottle at 6-months. This practice was more common among those who experienced marginal to very low levels of food security. Comparing by race/ethnicity, Latinx mothers were significantly less likely to introduce solids early. After controlling for sex, infants fed cereal in the bottle were consuming significantly more calories compared to their counterparts. Specifically, adding cereal into the bottle resulted in approximately 10% additional daily calorie intake among infants. Understanding how these feeding practices affect appetite development and weight status during infancy is warranted.

Breastfeeding might partially contribute to gut microbiota construction and stabilization of propionate metabolism in cesarean-section infants

PURPOSE

This study was aimed to determine how delivery mode and feeding pattern influence the infant's gut microbiota construction and the variation of fecal microbial metabolites from a birth cohort.

METHODS

Fecal samples collected from 61 full-term born Chinese infants at four time points: day 0, day 7, month 1, and month 3. Based on delivery mode (vaginal delivery [V] or cesarean section [C]) and feeding pattern (breastfeeding [B] or mixed feeding [M]), infants were divided into four groups, namely VB, CB, VM, and CM groups. The gut microbiota composition and bacterial diversity were assessed using 16S rRNA sequencing. Short-chain fatty acid (SCFA) concentrations were determined via gas chromatography-mass spectrometry (GC-MS).

RESULTS

The CM group had a significantly higher relative abundance of Firmicutes (day 0 and month 1), Enterococcaceae (month 3), and Enterococcus (month 3) than the VB group and a significantly higher abundance of Firmicutes (month 1) and Blautia (month 3) than the CB group. The VB and CB groups exhibited a stable SCFA variation and a significantly lower level of propionate compared with the VM and CM groups. All groups showed an intense transition of enterotypes within 1 month and became stable at 3 months. The correlation between SCFA and enterotypes showed a significant positive correlation between Bifidobacteriaceae and acetate in the CB group (day 7 and month 3) and a significant positive correlation between Clostridiaceae and butyrate in the CB and VB groups (day 7 and month 3), respectively.

CONCLUSION

These results indicated that C-section was associated with higher abundance of the phylum Firmicutes and family Enterococcaceae, and intense fluctuation of SCFA, at least propionate. And breastfeeding might partially contribute to gut microbiota construction and stabilization propionate metabolism in cesarean-section infants.

Impact of complementary feeding on obesity risk

PURPOSE OF REVIEW

To discuss recent evidence on the influence of complementary feeding (CF) timing, content and feeding methods on childhood obesity risk.

RECENT FINDINGS

The evidence-base is limited by heterogeneity, risk of bias and the predominance of observational studies. The content of the diet and feeding practices are more influential than timing for obesity risk. There is limited evidence that CF introduction before 4 months may be associated with increased risk. Intake of animal protein, particularly dairy protein, may contribute to rapid weight gain; protein from infant/follow-on formula shows the most robust association with later obesity risk. Evidence linking sugar intake to obesity risk is limited, but intake should be as low as possible given there is no nutritional requirement. Responsive feeding (RF) practices may promote appropriate infant growth and reduce risk. The effect of baby-led weaning (BLW) is inconclusive.

SUMMARY

Recent evidence supports current recommendations to avoid high protein intakes, especially from infant/follow-on formula, for infants in high income countries; and to promote RF practices for all infants. Studies in low- and middle-income countries are required to define optimal CF practices given increasing rates of child obesity alongside double-burden malnutrition.

Microbial metabolites as modulators of the infant gut microbiome and host-microbial interactions in early life

The development of infant gut microbiome is a pivotal process affecting the ecology and function of the microbiome, as well as host health. While the establishment of the infant microbiome has been of interest for decades, the focus on gut microbial metabolism and the resulting small molecules (metabolites) has been rather limited. However, technological and computational advances are now enabling researchers to profile the plethora of metabolites in the infant gut, allowing for improved understanding of how gut microbial-derived metabolites drive microbiome community structuring and host-microbial interactions. Here, we review the current knowledge on development of the infant gut microbiota and metabolism within the first year of life, and discuss how these microbial metabolites are key for enhancing our basic understanding of interactions during the early life developmental window.

Timing of introduction of complementary foods, breastfeeding, and child cardiometabolic risk: a prospective multiethnic Asian cohort study

BACKGROUND

The timing of introduction of complementary foods and the duration of breastfeeding (BF) have been independently associated with child overweight and obesity; however, their combined influence on body fat partitioning and cardiometabolic risk is unclear.

OBJECTIVE

We investigated the associations of the timing of introduction of complementary foods, the duration of BF, and their interaction with child adiposity and cardiometabolic risk markers.

METHODS

We analyzed data from 839 children in the prospective Growing Up in Singapore Towards healthy Outcomes (GUSTO) cohort. Mothers reported the age at which infants were first fed complementary foods and BF duration, classified as early (≤4 mo) versus typical (>4 mo) complementary feeding (CF) and short (≤4 mo) versus long (>4 mo) duration of any BF, respectively. We measured adiposity and cardiometabolic risk markers at the age of 6 y and examined their associations with infant feeding patterns using multiple regression, adjusting for sociodemographics, parents' body mass index (BMI), maternal factors, birth weight for gestational age, and infant weight gain.

RESULTS

Of 839 children, 18% experienced early CF, whereas 54% experienced short BF. Short (vs. long) BF and early (vs. typical) CF were independently associated with higher z-scores of BMI [β (95% confidence interval), short BF, 0.18 standard deviation score (SDS) (-0.01, 0.38); early CF, 0.34 SDS (0.11, 0.57)] and sum of skinfolds [short BF, 1.83 mm (0.05, 3.61); early CF, 2.73 mm (0.55, 4.91)]. Children who experienced both early CF and short BF (vs. typical CF-long BF) had synergistically higher diastolic blood pressure [1.41 mmHg (-0.15, 2.97), P-interaction = 0.023] and metabolic syndrome score [0.81 (0.16, 1.47), P-interaction = 0.081]. Early CF-long BF (vs. early CF-short BF) was associated with a lower systolic blood pressure [-3.74 mmHg (-7.01, -0.48)], diastolic blood pressure [-2.29 mmHg (-4.47, -0.11)], and metabolic syndrome score [-0.90 (-1.80, 0.00)].

CONCLUSIONS

A combination of early CF and short BF was associated with elevated child adiposity and cardiometabolic markers. Longer BF duration may protect against cardiometabolic risk associated with early CF. This trial was registered at clinicaltrials.gov as NCT01174875.

Association between maternal antibiotic exposure during pregnancy and childhood obesity in the Japan Environment and Children's Study

BACKGROUND

The association between maternal antibiotic exposure during pregnancy and childhood obesity is still unclear.

OBJECTIVES

The study aimed to evaluate the association between prenatal exposure to antibiotics and obesity at age 3 years using data from a large Japanese birth cohort.

METHODS

The Japan Environment and Children's Study is a nationwide birth cohort study. In this study, singleton vaginal full-term births were included. Obesity was defined as body mass index ≥95th percentile according to child growth standards. Prenatal antibiotic exposure was defined as antimicrobial agent use during pregnancy and was collected from maternal interviews and medical record transcripts. Logistic regression analysis was performed to evaluate the association of prenatal antibiotic exposure with child obesity at 3 years.

RESULTS

In the crude and adjusted models with all children, maternal antibiotic exposure during pregnancy showed a marginal relationship with child obesity at 3 years. In the analyses according to exposure period and sex, exposure to antibiotics during the second/third trimester was significantly associated with obesity at the age of 3 years in female infants, but not in male infants, although the exposure during the first trimester was not in both sexes.

CONCLUSION

Maternal antibiotic exposure during mid/late pregnancy may result in child obesity.

How Metabolomics Provides Novel Insights on Celiac Disease and Gluten-Free Diet: A Narrative Review

Celiac disease (CD) is an inflammatory autoimmune disorder triggered by the ingestion of gluten from wheat and other cereals. Nowadays, its positive diagnosis is based on invasive approaches such as the histological examination of intestinal biopsies and positive serology screening of antibodies. After proven diagnosis, the only admissible treatment for CD individuals is strict life-long adherence to gluten-free diet (GFD), although it is not a conclusive therapy. Acting by different mechanisms and with different etiologies, both CD and GFD have a great impact on gut microbiota that result in a different taxa composition. Altered production of specific metabolites reflects these microbiota changes. In this light, the currently available literature reports some suggestions about the possible use of specific metabolites, detected by meta-omics analyses, as potential biomarkers for a CD non-invasive diagnosis. To highlight insights about metabolomics application in CD study, we conducted a narrative dissertation of selected original articles published in the last decade. By applying a systematic search, it clearly emerged how the metabolomic signature appears to be contradictory, as well as poorly investigated.

The establishment of the gut microbiota in 1-year-aged infants: from birth to family food

Purpose

With the aim of characterizing the gastrointestinal (GI) microbiota and contextually determine how different prenatal, perinatal, and postnatal factors affected its composition in early childhood, infants were enrolled in a longitudinal-prospective study named “A.MA.MI.” (Alimentazione MAmma e bambino nei primi MIlle giorni; NCT04122612, October 2019).

Methods

Forty-five fecal samples were collected at 12 months of infants’ age, identified as the 3rd follow-up (T3). The evaluated variables were pre-gestational weight and weight gain during pregnancy, delivery mode, feeding, timing of weaning, and presence/absence of older siblings. Fecal alpha and beta-diversities were analyzed. Noteworthy, to determine the impact of the influencing factors, multivariate analyses were conducted.

Results

At T3, all prenatal and perinatal variables did not result to be significant whereas, among the postnatal variables, type of milk-feeding and weaning showed the greatest contribution in shaping the microbiota. Although aged 1 year, infants exclusively breastfed until 6 months were mainly colonized by Lactobacillaceae and Enterobacteriaceae. Differently, Bacteroidaceae characterized the microbiota of infants that were never breastfed in an exclusive way. Moreover, although an early introduction of solid foods determined higher values of Faith’s PD, high abundances of Ruminococcaceae and Faecalibacterium mainly associated with infants weaned after the 4th month of age.

Conclusion

The microbial colonization during the first year of life is likely affected by a simultaneous effect of multiple variables playing a significant role at different times. Therefore, these data contribute to add evidence concerning the complex multifactorial interaction between GI microbiota and various stimuli affecting infants during the early stages of life.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-022-02822-1.

Fecal microbiota relationships with childhood obesity: A scoping comprehensive review

Childhood obesity is a costly burden in most regions with relevant and adverse long-term health consequences in adult life. Several studies have associated excessive body weight with a specific profile of gut microbiota. Different factors related to fecal microorganism abundance seem to contribute to childhood obesity, such as gestational weight gain, perinatal diet, antibiotic administration to the mother and/or child, birth delivery, and feeding patterns, among others. This review reports and discusses diverse factors that affect the infant intestinal microbiota with putative or possible implications on the increase of the obesity childhood rates as well as microbiota shifts associated with excessive body weight in children.

Impact of early life nutrition on gut health in children: a prospective clinical study

INTRODUCTION

The first 1000 days of life could contribute to individual susceptibility to the later development of chronic non-communicable diseases. Nutrition in early life appears to be an important determinant factor for a sustainable child's health. In this study, we propose to investigate the impact of exclusive breast feeding on gut health in children.

METHODS AND ANALYSIS

A prospective cohort of newborns (n=350) will be recruited at birth and followed up to 4 years of age. The main objective is to evaluate the link between exclusive breast feeding for at least 3 months and the gut health of the child at 4 years. The primary endpoint of assessment of gut health will be based on the non-invasive measurement of faecal secretory IgA (sIgA) as a sensitive biomarker of the intestinal ecosystem. The presence of gastrointestinal disorders will be defined according to the clinical criteria of Rome IV. Information on parent's nutritional habits and life style, breastfeeding duration and child's complementary feeding will be collected along the follow-up. Cord blood cells and plasma at birth will be purified for further analysis. The meconium and stools collected at birth, 6 months, 2 years and 4 years of age will allow sIgA analysis.

ETHICS AND DISSEMINATION

This clinical study has obtained the approval from the national ethical committee. We plan to publish the results of the study in peer-review journals and by means of national and international conference.

TRIAL REGISTRATION NUMBER

NCT04195425.

Diet and the Microbiota-Gut-Brain Axis: Sowing the Seeds of Good Mental Health

Over the past decade, the gut microbiota has emerged as a key component in regulating brain processes and behavior. Diet is one of the major factors involved in shaping the gut microbiota composition across the lifespan. However, whether and how diet can affect the brain via its effects on the microbiota is only now beginning to receive attention. Several mechanisms for gut-to-brain communication have been identified, including microbial metabolites, immune, neuronal, and metabolic pathways, some of which could be prone to dietary modulation. Animal studies investigating the potential of nutritional interventions on the microbiota-gut-brain axis have led to advancements in our understanding of the role of diet in this bidirectional communication. In this review, we summarize the current state of the literature triangulating diet, microbiota, and host behavior/brain processes and discuss potential underlying mechanisms. Additionally, determinants of the responsiveness to a dietary intervention and evidence for the microbiota as an underlying modulator of the effect of diet on brain health are outlined. In particular, we emphasize the understudied use of whole-dietary approaches in this endeavor and the need for greater evidence from clinical populations. While promising results are reported, additional data, specifically from clinical cohorts, are required to provide evidence-based recommendations for the development of microbiota-targeted, whole-dietary strategies to improve brain and mental health.

Early Life Microbiota Colonization at Six Months of Age: A Transitional Time Point

Background

Early life gut microbiota is involved in several biological processes, particularly metabolism, immunity, and cognitive neurodevelopment. Perturbation in the infant’s gut microbiota increases the risk for diseases in early and later life, highlighting the importance of understanding the connections between perinatal factors with early life microbial composition. The present research paper is aimed at exploring the prenatal and postnatal factors influencing the infant gut microbiota composition at six months of age.

Methods

Gut microbiota of infants enrolled in the longitudinal, prospective, observational study “A.MA.MI” (Alimentazione MAmma e bambino nei primi MIlle giorni) was analyzed. We collected and analyzed 61 fecal samples at baseline (meconium, T0); at six months of age (T2), we collected and analyzed 53 fecal samples. Samples were grouped based on maternal and gestational weight factors, type of delivery, type of feeding, time of weaning, and presence/absence of older siblings. Alpha and beta diversities were evaluated to describe microbiota composition. Multivariate analyses were performed to understand the impact of the aforementioned factors on the infant’s microbiota composition at six months of age.

Results

Different clustering hypotheses have been tested to evaluate the impact of known metadata factors on the infant microbiota. Neither maternal body mass index nor gestational weight gain was able to determine significant differences in infant microbiota composition six months of age. Concerning the type of feeding, we observed a low alpha diversity in exclusive breastfed infants; conversely, non-exclusively breastfed infants reported an overgrowth of Ruminococcaceae and Flavonifractor. Furthermore, we did not find any statistically significant difference resulting from an early introduction of solid foods (before 4 months of age). Lastly, our sample showed a higher abundance of clostridial patterns in firstborn babies when compared to infants with older siblings in the family.

Conclusion

Our findings showed that, at this stage of life, there is not a single factor able to affect in a distinct way the infants’ gut microbiota development. Rather, there seems to be a complex multifactorial interaction between maternal and neonatal factors determining a unique microbial niche in the gastrointestinal tract.