Milk-fed Infants Research Articles

Networks of human milk microbiota are associated with host genomics, childhood asthma, and allergic sensitization

The human milk microbiota (HMM) is thought to influence the long-term health of offspring. However, its role in asthma and atopy and the impact of host genomics on HMM composition remain unclear. Through the CHILD Cohort Study, we followed 885 pregnant mothers and their offspring from birth to 5 years and determined that HMM was associated with maternal genomics and prevalence of childhood asthma and allergic sensitization (atopy) among human milk-fed infants. Network analysis identified modules of correlated microbes in human milk that were associated with subsequent asthma and atopy in preschool-aged children. Moreover, reduced alpha-diversity and increased Lawsonella abundance in HMM were associated with increased prevalence of childhood atopy. Genome-wide association studies (GWASs) identified maternal genetic loci (e.g., ADAMTS8, NPR1, and COTL1) associated with HMM implicated with asthma and atopy, notably Lawsonella and alpha-diversity. Thus, our study elucidates the role of host genomics on the HMM and its potential impact on childhood asthma and atopy.

Human milk oligosaccharides are associated with maternal genetics and respiratory health of human milk-fed children

Breastfeeding provides many health benefits, but its impact on respiratory health remains unclear. This study addresses the complex and dynamic nature of the mother-milk-infant triad by investigating maternal genomic factors regulating human milk oligosaccharides (HMOs), and their associations with respiratory health among human milk-fed infants. Nineteen HMOs are quantified from 980 mothers of the CHILD Cohort Study. Genome-wide association studies identify HMO-associated loci on chromosome 19p13.3 and 19q13.33 (lowest P = 2.4e–118), spanning several fucosyltransferase (FUT) genes. We identify novel associations on chromosome 3q27.3 for 6′-sialyllactose (P = 2.2e–9) in the sialyltransferase (ST6GAL1) gene. These, plus additional associations on chromosomes 7q21.32, 7q31.32 and 13q33.3, are replicated in the independent INSPIRE Cohort. Moreover, gene-environment interaction analyses suggest that fucosylated HMOs may modulate overall risk of recurrent wheeze among preschoolers with variable genetic risk scores (P < 0.01). Thus, we report novel genetic factors associated with HMOs, some of which may protect the respiratory health of children.

Parental engagement with complementary feeding information in the United Kingdom: A qualitative evidence synthesis.

Complementary feeding is the process of introducing solid foods to milk-fed infants (also known as weaning). Current UK guidance states that complementary feeding should occur around 6 months but not before 4 months. This systematic review explores how parents in the UK, with an infant under 24 months of age, engage with sources of information and advice about complementary feeding. Engaging with sources of information can influence parents' feeding choices and so a better understanding of parents' information behaviours can improve service provisions. Six databases were searched, identifying 15 relevant qualitative studies with the predefined criteria. Data from each study were coded line by line allowing for a synthesis of higher analytical themes. Using thematic synthesis, four main themes were observed: (1) trust and rapport-parents valued information from a trusted source (2), accessibility-information needs were often time sensitive, and parents showed varying levels of understanding, (3) adapting feeding plans-often influenced by practicalities (4), being a good parent-feeding plans were changed to comply with societal ideas of 'good parenting'. Thereview concluded that parents receive information and advice about complementary feeding from multiple sources and are highly motivated to seek further information. The scope of this novel review explored the parental experience of finding, receiving and engaging with information sources and how this may or may not have influenced their feeding behaviours. Thereview has provided a new perspective to add to the growing body of literature that focuses on the experience of feeding an infant.

P07-008-23 Dietary Intake Among Lactating Mothers of Hospitalized Human Milk-Fed Very Preterm Infants

P07-008-23 Dietary Intake Among Lactating Mothers of Hospitalized Human Milk-Fed Very Preterm Infants

What are Normal Defecation Patterns in Healthy Children up to Four Years of Age? A Systematic Review and Meta-Analysis

To summarize available data on defecation frequency and stool consistency of healthy children up to age 4 in order to estimate normal references values. Systematic review including cross-sectional, observational, and interventional studies published in English, that reported on defecation frequency and/or stool consistency in healthy children 0-4years old. Seventy-five studies were included with 16 393 children and 40 033 measurements of defecation frequency and/or stool consistency. Based on visual inspection of defecation frequency data, a differentiation was made between two age categories: young infants (0-14weeks old) and young children (15weeks-4years old). Young infants had a mean defecation frequency of 21.8 per week (95 % CI, 3.9-35.2) compared with 10.9 (CI, 5.7-16.7) in young children (P<.001). Among young infants, human milk-fed (HMF) infants had the highest mean defecation frequency per week (23.2 [CI, 8.8-38.1]), followed by formula-fed (FF) infants (13.7 [CI 5.4-23.9]), and mixed-fed (MF) infants (20.7 [CI, 7.0-30.2]). Hard stools were infrequently reported in young infants (1.5%) compared with young children (10.5%), and a reduction in the frequency of soft/watery stools was observed with higher age (27.0% in young infants compared with 6.2% in young children). HMF young infants had softer stools compared with FF young infants. Young infants (0-14weeks old) have softer and more frequent stools compared with young children (15weeks-4years old).

Gut Microbiome and Small RNA Integrative-Omic Perspective of Meconium and Milk-FED Infant Stool Samples.

The human gut microbiome plays an important role in health, and its initial development is conditioned by many factors, such as feeding. It has also been claimed that this colonization is guided by bacterial populations, the dynamic virome, and transkingdom interactions between host and microbial cells, partially mediated by epigenetic signaling. In this article, we characterized the bacteriome, virome, and smallRNome and their interaction in the meconium and stool samples from infants. Bacterial and viral DNA and RNA were extracted from the meconium and stool samples of 2- to 4-month-old milk-fed infants. The bacteriome, DNA and RNA virome, and smallRNome were assessed using 16S rRNA V4 sequencing, viral enrichment sequencing, and small RNA sequencing protocols, respectively. Data pathway analysis and integration were performed using the R package mixOmics. Our findings showed that the bacteriome differed among the three groups, while the virome and smallRNome presented significant differences, mainly between the meconium and stool of milk-fed infants. The gut environment is rapidly acquired after birth, and it is highly adaptable due to the interaction of environmental factors. Additionally, transkingdom interactions between viruses and bacteria can influence host and smallRNome profiles. However, virome characterization has several protocol limitations that must be considered.

Age-dependent associations of human milk oligosaccharides with body size and composition up to 4 years of age

BackgroundHuman milk oligosaccharides (HMOs) are major components of human milk that may mediate its beneficial effects on infant growth. ObjectivesTo investigate relationships between HMO concentrations in milk at 6 wk postpartum and anthropometry to 4 y of age in human milk-fed infants. MethodsMilk samples were collected from 292 mothers at 6 wk (median 6.0 wk; range 3.3, 11.1] postpartum in a longitudinal, population-derived cohort. Of the infants, 171 were exclusively human milk-fed to 3 mo of age and 127 to 6 mo. Concentrations of 19 HMOs were quantified using high-performance liquid chromatography. Maternal secretor status (n = 221 secretors) was determined from 2’-fucosyllactose (2’FL) concentration. We calculated z-scores for child weight, length, head circumference, summed triceps and subscapular skinfold thicknesses, and weight-for-length at 6 wk, 6 mo, 12 mo, and 4 y. We investigated associations of secretor status and each HMO measure with change from birth for each z-score using linear mixed-effects models. ResultsMaternal secretor status was not associated with anthropometric z-scores up to 4 y of age. Several HMOs were associated with z-scores at 6 wk and 6 mo, predominantly within secretor status subgroups. Higher levels of 2’FL were associated with greater weight [β = 0.91 increase in z-score per SD increase log-2’FL, 95% CI (0.17, 1.65)] and length [β = 1.22, (0.25, 2.20)] in children born to secretor mothers, but not body composition measures. Higher lacto-N-tetraose was associated with greater weight [β = 0.22, (0.02, 0.41)] and length (β = 0.30, (0.07, 0.53)] among children born to nonsecretor mothers. Several HMOs were associated with anthropometric measures at 12 mo and 4 y of age. ConclusionsMilk HMO composition at 6 wk postpartum is associated with several anthropometry measures up to 6 mo of age in a potential secretor status-specific manner, with largely different HMOs associating with anthropometry from 12 mo to 4 y of age.

Potential of Bifidobacterium lactis IDCC 4301 isolated from breast milk-fed infant feces as a probiotic and functional ingredient.

Probiotics provide important health benefits to the host by improving intestinal microbial balance and have been widely consumed as dietary supplements. In this study, we investigated whether Bifidobacterium lactis IDCC 4301 (BL), isolated from feces of breast milk-fed infants, is safe to consume. Based on the guidelines established by the European Food Safety Authority (EFSA), safety tests such as antibiotic susceptibility, hemolysis, toxic compound formation (i.e., biogenic amine and d-lactate), single-dose acute oral toxicity, and extracellular enzymatic activities were performed. In addition, toxigenic genes, antibiotic resistance genes, and mobile genetic elements were investigated by analyzing the genome sequence of BL. BL was susceptible to eight antibiotics except for vancomycin and the absence of transferable resistance in the genome of this strain implied that vancomycin resistance is likely to be intrinsic. With regard to phenotypic characteristics, there was no concern of toxicity of this strain. Furthermore, BL utilized various carbohydrates and their conjugates through the activity of various endogenous carbohydrate-utilizing enzymes. Interestingly, the supernatant of the BL showed strong antipathogenic activity against various infectious pathogens. Therefore, we suggest that BL should be a safe probiotic and can be used as a functional ingredient in the food, cosmetic, and pharmaceutical industries.

Human Milk Oligosaccharides and Infant Neurodevelopment: A Narrative Review.

The objective of this narrative review was to synthesize the literature on human milk oligosaccharides (HMOs) and neurodevelopmental outcomes in human milk-fed infants. We conducted a scoping review of the literature indexed in PubMed reporting observational or interventional studies on HMO exposure in relation to psychometric measures in infants. Studies were characterized based on study design and definitions of HMO exposure and neurodevelopmental outcomes. Six studies were identified; all were observational in design, and five were conducted in full-term infants. Sample sizes ranged from 35-659 infants. HMOs were defined as individual concentrations or relative abundances assessed at 1 and/or 6 months of age. Studies accounted for differences in HMO exposure based on maternal secretor status. Neurodevelopmental outcomes were assessed between 6 and 24 months of age and included four domains. Studies in full-term infants reported that total and individual fucosylated and sialylated HMOs were positively associated with cognitive, language, and motor skill domains between 18 and 24 months of age, while the single study in preterm infants reported no statistically significant findings in the full cohort. The presence of a maternal secretor did not consistently alter the associations between HMO exposure and neurodevelopmental outcomes. Emerging evidence from observational studies suggests that HMO exposure may be beneficial for neurodevelopment in infants.

424 - The gut microbiome of human milk-fed infants born extremely preterm randomized to receive increased enteral protein intake

424 - The gut microbiome of human milk-fed infants born extremely preterm randomized to receive increased enteral protein intake

Human Milk Feeding for Septic Newborn Infants Might Minimize Their Exposure to Ventilation Therapy.

Background. It has been well established that human milk feeding contributes to limiting lung diseases in vulnerable neonates. The primary aim of this study was to compare the need for mechanical ventilation between human milk-fed neonates with sepsis and formula-fed neonates with sepsis. Methods. All late preterm and full-term infants from a single center with sepsis findings from 2002 to 2017 were identified. Data on infant feeding during hospital admission were also recorded. Multivariate logistic regression analyses were performed to assess the impact of feeding type on ventilation support and main neonatal morbidities. Results. The total number of participants was 322 (human milk group = 260; exclusive formula group = 62). In the bivariate analysis, 72% of human milk-fed neonates did not require oxygen therapy or respiratory support versus 55% of their formula-fed counterparts (p < 0.0001). Accordingly, invasive mechanical ventilation was required in 9.2% of any human milk-fed infants versus 32% of their exclusively formula-fed counterparts (p = 0.0085). These results held true in multivariate analysis; indeed, any human milk-fed neonates were more likely to require less respiratory support (OR = 0.44; 95% CI:0.22, 0.89) than those who were exclusively formula-fed. Conclusion. Human milk feeding may minimize exposure to mechanical ventilation.

More evidence: Mothers’ own milk is personalized medicine for very low birthweight infants

“Human milk sources and fortification: Impact on fecal microbiota and calprotectin in premature infants” highlights improved outcomes in predominantly mothers’ own milk-fed versus predominantly pasteurized donor human milk-fed VLBW infants, regardless of fortifier type. Research and practice implications are reviewed.

Enteral Iron Supplementation in Preterm or Low Birth Weight Infants: A Systematic Review and Meta-analysis

Iron is needed for growth and development of infants globally, but preterm and low birth weight (LBW) infants are at risk for severe iron deficiencies. To assess the effect of enteral iron supplementation on mortality, morbidity, growth, and neurodevelopment outcomes in preterm or LBW infants fed human milk. Secondary objectives were to assess the effect on biomarkers and dose and timing. Data sources include PubMed, Embase and Cochrane Library databases to March 16, 2021. Study Selection includes controlled or quasi experimental study designs. Two reviewers independently extracted data. Eight trials (eleven reports; 1093 participants, 7 countries) were included. No trials reported mortality. At latest follow-up, there was little effect on infection (very low certainty evidence, 4 studies, 401 participants, relative risk [RR] 0.98, 95% confidence interval [95% CI] 0.56 to 1.73, I2 = 0.00%) and necrotising enterocolitis (3 studies, 375 participants, RR 1.47, 95% CI 0.68 to 3.20, I2 = 0.00%). There was an increase in linear growth (length) (moderate certainty evidence, 3 studies, 384 participants, mean difference 0.69 cm, 95% CI 0.01 to 1.37, I2 = 0%) but little effect on weight, head circumference, or cognitive development. There was an improvement in anemia (moderate certainty evidence, 2 studies, 381 participants, RR 0.25, 95% CI 0.10 to 0.62, I2 = 0.00%) but no effect on serum ferritin. Limitations include heterogeneity in the included studies. There are important benefits for human milk-fed preterm and LBW infants from enteral iron supplementation. However, more randomized control trials are required to improve the certainty of evidence.

Preterm Infant Fecal Microbiota and Metabolite Profiles Are Modulated in a Probiotic Specific Manner.

To compare the impact of two probiotic supplements on fecal microbiota and metabolites, as well as on gut inflammation in human milk-fed preterm infants. In this single-center observational cohort study, we assessed the effects of Bifidobacterium longum subsp. infantis or Lactobacillus reuteri supplementation on the infant gut microbiota by 16S rRNA gene sequencing and fecal metabolome by 1 H nuclear magnetic resonance spectroscopy. Fecal calprotectin was measured as a marker of enteric inflammation. Aliquots of human or donor milk provided to each infant were also assessed to determine human milk oligosaccharide (HMO) content. As expected, each probiotic treatment was associated with increased proportions of the respective bacterial taxon. Fecal HMOs were significantly higher in L. reuteri fed babies despite similar HMO content in the milk consumed. Fecal metabolites associated with bifidobacteria fermentation products were significantly increased in B. infantis supplemented infants. Fecal calprotectin was lower in infants receiving B. infantis relative to L. reuteri ( P &lt; 0.01, Wilcoxon rank-sum test) and was negatively associated with the microbial metabolite indole-3-lactate (ILA). This study demonstrates that supplementing an HMO-catabolizing Bifidobacterium probiotic results in increased microbial metabolism of milk oligosaccharides and reduced intestinal inflammation relative to a noncatabolizing Lactobacillus probiotic in human milk-fed preterm infants. In this context, Bifidobacterium may provide greater benefit in human milk-fed infants via activation of the microbiota-metabolite-immune axis.

Coronavirus Disease 2019 Vaccine Booster Effects Are Seen in Human Milk Antibody Response.

Infants remain at high risk for severe coronavirus disease 2019 (COVID-19). Human milk contains high levels of protective SARS CoV-2 specific antibodies post-infection and primary vaccine series, but levels decline over time. We hypothesized that the COVID-19 booster vaccine augment antibody production and the protection afforded to human milk-fed infants. We prospectively enrolled pregnant or lactating mothers planning to receive COVID-19 vaccination. We measured human milk IgG, IgA, and IgM antibodies targeting the SARS CoV-2 receptor binding domain within the spike protein and human milk neutralization activity against SARS CoV-2 in 10 lactating mothers from pre-COVID-19 primary series vaccine to post-booster dose. Human milk SARS CoV-2 specific IgG increased significantly from pre- to post-booster levels (median OD 0.33 vs. 2.02, P = 0.002). The IgG levels post-booster were even higher than the peak level after the primary series (2.02 vs. 0.95, P = 0.03). The increase in SARS CoV-2 specific IgA levels was not significant (0.10 vs. 0.33, P = 0.23). There was a strong correlation between paired maternal blood and milk IgG and IgA levels (IgG rho 0.52, P < 0.001, IgA rho 0.31, P = 0.05). Post-booster neutralizing activity was elevated compared to pre-booster levels (66% vs. 12% inhibition, P = 0.002). COVID-19 vaccine booster elicits SARS CoV-2 specific antibodies in human milk at higher levels compared to the initial primary series. This finding suggests that three doses of COVID-19 mRNA vaccination leads to improved mucosal response in human milk and reinforces current guidance recommending all pregnant or lactating mothers receive full COVID-19 vaccine courses with a booster dose.

Human Milk SARS-CoV-2 Antibodies up to 6 Months After Vaccination.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibodies have been detected in human milk up to 6 weeks post-coronavirus disease 2019 (COVID-19) vaccination. We evaluated SARS-CoV-2-specific antibodies, neutralization activity, effect of pasteurization, and persistence through 6 months after vaccination. This prospective longitudinal study enrolled 30 pregnant or lactating women. SARS-CoV-2 antibodies and neutralization capacity were analyzed using an enzyme-linked immunosorbent assay compared at prevaccination and 1, 3, and 6 months postvaccination, and through Holder pasteurization. Human milk SARS-CoV-2-specific IgG levels peaked at 1 month postvaccination and persisted above prevaccination levels for at least 6 months (P = .005). SARS-CoV-2-specific IgA was detected at 1 and 3 months (both P < .001) but waned by 6 months compared with baseline (P = .07). Milk SARS-CoV-2-specific IgG and IgA correlated with serum IgG at the same time point (R2 = 0.37, P < .001 and R2 = 0.19, P < .001). Neutralization activity was seen in 83.3%, 70.4%, and 25.0% of milk samples at 1, 3, and 6 months postvaccination. Neutralization most strongly correlated with SARS-CoV-2-specific IgG (R2 = 0.57, P < .001). Pre- and postpasteurization samples showed similar IgG (0.84 vs 1.07, P = .36) and neutralizing activity (57.7% vs 58.7% inhibition, P = .27), but lower IgM and IgA levels postpasteurization (0.09 vs 0.06, P = .004 and 0.21 vs 0.18, P = .043). The data suggest that human milk SARS-CoV-2-specific antibodies may be available to milk-fed infants for up to 6 months. In addition, donor milk from vaccinated mothers retain IgG and neutralizing activity.

Term infant formula supplemented with milk-derived oligosaccharides shifts the gut microbiota closer to that of human milk-fed infants and improves intestinal immune defense: a randomized controlled trial

ABSTRACTBackgroundBovine milk-derived oligosaccharides (MOS) containing primarily galacto-oligosaccharides with inherent concentrations of sialylated oligosaccharides can be added to infant formula to enhance the oligosaccharide profile.ObjectiveTo investigate the effects of an MOS-supplemented infant formula on gut microbiota and intestinal immunity.MethodsIn a double-blind, randomized, controlled trial, healthy term formula-fed infants aged 21–26 d either received an intact protein cow milk-based formula (control group, CG, n = 112) or the same formula containing 7.2 g MOS/L (experimental group, EG, n = 114) until the age of 6 mo. Exclusively human milk-fed infants (HFI, n = 70) from an observational study served as the reference. Fecal samples collected at baseline, and the ages of 2.5 and 4 mo were assessed for microbiota (16S ribosomal RNA-based approaches), metabolites, and biomarkers of gut health and immune response.ResultsAged 2.5 and 4 mo, redundancy analysis (P = 0.002) and average phylogenetic distance (P < 0.05) showed that the overall microbiota composition in EG was different from CG and closer to that of HFI. Similarly, EG caesarean-born infants were different from CG caesarean- or vaginally born infants and approaching HFI vaginally born infants. Relative bifidobacteria abundance was higher in EG compared with CG (P < 0.05) approaching HFI. At the age of 4 mo, counts of Clostridioides difficile and Clostridium perfringens were ∼90% (P < 0.001) and ∼65% (P < 0.01) lower in EG compared with CG, respectively. Geometric LS mean (95% CI) fecal secretory IgA in EG was twice that of CG [70 (57, 85) compared with 34 (28, 42) mg/g, P < 0.001] and closer to HFI. Fecal oral polio vaccine-specific IgA was ∼50% higher in EG compared with CG (P = 0.065). Compared with CG, EG and HFI had lower fecal calcium excretion (by ∼30%, P < 0.005) and fecal pH (P < 0.001), and higher lactate concentration (P < 0.001).ConclusionsInfant formula with MOS shifts the gut microbiota and metabolic signature closer to that of HFI, has a strong bifidogenic effect, reduces fecal pathogens, and improves the intestinal immune response.

Dental caries and associated risk factors in 13- to 18-month-old infants receiving breast or formula milk feeding: A cross-sectional study.

The association between breast milk feeding and dental caries risk in children remains controversial. Moreover, it is unclear whether risk factors for caries differ between breast milk-fed and formula milk-fed infants. To investigate dental caries in 13- to 18-month-old infants receiving breast milk or formula milk feeding and associated risk factors. One hundred and sixty-six 13- to 18-month-old infants were recruited from a tertiary hospital in Bangkok, Thailand. Information on feeding practices, demographics, and potential risk factors was collected using a caregiver questionnaire. Carious lesions were identified by visual and tactile examination. The Chi-squared test, Mann-Whitney U test, and logistic regression model were used for statistical analysis. The prevalence of caries in breast milk- and formula milk-fed infants was 31.8% and 36.0%, respectively, with no statistically significant difference (p=.579). Among all children, having dental plaque deposition on more than one third of the crown (adjusted OR (aOR): 15.11%; 95% CI: 6.11-37.35) and sleeping while milk feeding (aOR: 2.20%; 95%CI: 1.01-4.77) were associated with dental caries. In subgroup analysis, however, sleeping while milk feeding increased caries risk in the formula milk-fed group only (aOR: 2.95%; 95%CI: 1.07-8.12). The type of milk feeding was not associated with dental caries, whereas dental plaque and sleeping while milk feeding increased the odds of having dental caries in this population.

Fecal Bacterial Communities Differ by Lactation Status in Postpartum Women and Their Infants.

Previous research examined effects of human milk on the infant gut microbiota, but little attention has been given to the microbiota of lactating women. To determine associations between exclusive human milk feeding and gut microbiota characteristics in mothers and infants at 6-weeks postpartum. A sample of mother-infant dyads (N = 24) provided fecal samples and questionnaire responses at 6-weeks postpartum as part of the Pregnancy, EAting & POstpartum Diapers study. Deoxyribonucleic acid was extracted from stool samples, followed by (V4) 16S ribosomal ribonucleic acid gene amplicon sequencing. Alpha and beta diversity, in addition to taxa differences, were compared by human milk exposure status, exclusive versus non-exclusive. A subset of dyads (those exclusively fed human milk; n = 14) was analyzed for shared bifidobacterial species using polymerase chain reaction. Alpha diversity was significantly lower in exclusively human milk-fed infants. Maternal lactation status (exclusive vs. partial) and Shannon diversity were associated in univariate analysis but were no longer associated in multivariable regression including body mass index category in the model. Beta diversity (Sorensen dissimilarity) of fecal samples from women and infants was significantly associated with human milk feeding. Of six infants with Bifidobacterium longum subspecies longum in their fecal samples, all their mothers shared the same species. Maternal gut microbiotas differ by lactation status, a relationship potentially confounded by body mass index category. Further research is needed to identify whether lactation directly influences the maternal gut microbiota, which may be another mechanism by which lactation influences health.

The Abundance of Human Milk Oligosaccharide (HMO)-Metabolizing Genes in Fecal Samples from Six-Month-Old Human Infants.

Herein, we report the abundance and prevalence of HMO-metabolizing genes, specifically those of Bifidobacterium infantis, in fecal samples from human infants. Forty dyads were enrolled, and each mother collected a fecal sample from her infant at six months of age. Genomic DNA was extracted, and quantitative real-time PCR was used to determine gene abundance. The mode of delivery was not associated with gene abundance. Several gene regions, Sia (a sialidase), B. inf (16S), and GH750 (a glycoside hydrolase), were more abundant in the feces of human milk-fed infants (p < 0.05). Others, Sia and HC bin (16S), tended to be less abundant when a larger percentage of an infant’s diet consisted of solids (p < 0.10). When accounting for solid food intake, human milk exposure was positively associated with Sia and B. inf (p < 0.05) and tended to be related to the abundance of the GH750 and HC bin (p < 0.10) gene regions. With further development and validation in additional populations of infants, these assays could be used to group samples by dietary exposure even where no record of dietary intake exists. Thus, these assays would provide a method by which infant human milk intake can be assessed quickly in any well-equipped molecular biology laboratory.