Lactose-reduced infant formula with added corn syrup solids is associated with a distinct gut microbiota in Hispanic infants

Infant consumption of 100% lactose-based and reduced lactose infant formula in the United States: Review of NHANES data from 1999 to 2020

OBJECTIVES

An acceptable alternative to human milk is US Food and Drug Administration (US FDA)-registered infant formula, which must meet the requirements of the US FDA Infant Formula Act. Human milk contains lactose, but some infant formulas may contain alternative carbohydrate sources such as corn syrup solids, maltodextrin, and sucrose. Recent research shows that infant-formula made with corn syrup solids may be associated with increased obesity risk in the first 5 years of life. A previous study found that of all formulas purchased, 59.0% were lactose-reduced. More US infants consume infant formula with nonlactose carbohydrates more frequently than is medically necessary. The purpose of this study is to use National Health and Nutrition Examination Survey (NHANES) data to describe the type and prevalence of nonlactose carbohydrates consumed in infant formula.

METHODS

NHANES data from 1999 to 2020 was used to perform cross-sectional analyses and analyses of comparison of prevalence over time on consumption of nonlactose carbohydrate sources in infant formulas.

RESULTS

We identified 3709 unique infant IDs associated with 36,084 feeding sessions. More than half of the feeding sessions involved a formula with at least one nonlactose carbohydrate. Feeding sessions involving a formula with at least one nonlactose carbohydrate increased by 163% from 1999-2004 to 2017-2020; formulas containing single or multiple nonlactose carbohydrate types account for the increase in prevalence.

CONCLUSIONS

This study highlights an increase in the consumption of infant formula containing a nonlactose carbohydrate. More studies are needed to understand the short- and long-term effects of early exposure to these carbohydrates.

Maternal Diet Associated with Oligosaccharide Abundances in Human Milk from Latina Mothers

Growing evidence indicates that human milk oligosaccharides (HMOs) are important bioactive compounds that enhance health and developmental outcomes in breastfed babies. Maternal dietary intake likely contributes to variation in HMO composition, but studies identifying diet-HMO relationships are few and inconsistent. This study aimed to investigate how the maternal intake of macronutrients and micronutrients-specifically proteins, fats, vitamins, and minerals-associated with HMOs at 1 month (n = 210), 6 months (n = 131), and 12 months postpartum (n = 84). Several associations between maternal dietary factors and HMO profiles were identified utilizing partial correlation analysis. For example, maternal free sugar (rho = -0.02, p < 0.01), added sugar (rho = -0.22, p < 0.01), and sugary sweetened beverage (rho = -0.22, p < 0.01) intake were negatively correlated with the most abundant HMO, 2'-fucosyllactose (2'-FL), at 1 month, suggesting that higher sugar consumption was associated with reduced levels of 2'-FL. Further, vitamins D, C, K, and the minerals zinc and potassium were positively correlated with 2'-FL at 1 month (pAll < 0.05). For the longitudinal analysis, a mixed-effects linear regression model revealed significant associations between maternal vitamin intake and HMO profiles over time. For example, for each unit increase in niacin intake, there was a 31.355 nmol/mL increase in 2'-FL concentration (p = 0.03). Overall, the results provide additional evidence supporting a role for maternal nutrition in shaping HMO profiles, which may inform future intervention strategies with the potential of improving infant growth and development through optimal HMO levels in mothers' milk.

The neighborhood food environment modifies the association between infant feeding and childhood obesity

BACKGROUND

The Special Supplemental Nutrition Program for Women, Infants and Children (WIC) issues infant formula to infants who are not fully breastfed, and prior research found elevated obesity risk among children receiving lactose-reduced infant formula with corn syrup solids (CSSF) issued by WIC. This study was conducted to evaluate associations between a broader set of specialty infant formulas issued by WIC and child obesity risk, whether neighborhood context (e.g. neighborhood food environment) modifies associations, and whether racial/ethnic disparities in obesity are partly explained by infant formula exposure and neighborhood context.

METHODS

WIC administrative data, collected from 2013-2020 on issued amount (categorical: fully formula fed, mostly formula fed, mostly breastfed, fully breastfed) and type of infant formula (standard cow's milk formula, and three specialty formulas: any CSSF, any soy-based formula, and any cow's milk-based formula with added rice starch) and obesity at ages 2-4 years (defined as a Body Mass Index z-score ≥ 95th percentile according to World Health Organization growth standard) were used to construct a cohort (n = 59,132). Associations of infant formula exposures and race/ethnicity with obesity risk were assessed in Poisson regression models, and modification of infant feeding associations with obesity by neighborhood context was assessed with interaction terms.

RESULTS

Any infant formula exposure was associated with significantly higher obesity risk relative to fully breastfeeding. Receipt of a CSSF was associated with 5% higher obesity risk relative to the standard and other specialty infant formulas (risk ratio 1.05, 95% confidence interval 1.02, 1.08) independent of breastfeeding duration and receipt of other specialty infant formulas. The association between CSSF and obesity risk was stronger in neighborhoods with healthier food environments (10% higher risk) compared to less healthy food environments (null). Racial/ethnic disparities in obesity risk were robust to adjustment for infant formula exposure and neighborhood environment.

CONCLUSIONS

Among specialty infant formulas issued by WIC, only CSSFs were associated with elevated obesity risk, and this association was stronger in healthier food environments. Future research is needed to isolate the mechanism underlying this association.

Influence of infant microbiome on health and development

The microbiome is a complex ecosystem comprising microbes, their genomes, and the surrounding environment. The microbiome plays a critical role in early human development, including maturation of the host immune system and gastrointestinal tract. Multiple factors, including diet, anti-biotic use, and other environmental exposures, influence the establishment of the microbiome during infancy. Numerous studies have identified associations between the microbiome and neonatal diseases, including necrotizing enterocolitis, sepsis, and malnutrition. Furthermore, there is compelling evidence that perturbation of the microbiome in early life can have lasting developmental effects that increase an individual's risk for immune and metabolic diseases in later life. Supplementation of the microbiome with probiotics reduces the risk of necrotizing enterocolitis and sepsis in at-risk infants. This review focuses on the structure and function of the infant microbiome, the environmental and clinical factors that influence its assembly, and its impact on infant health and development.

Human Milk Components and the Infant Gut Microbiome at 6 Months: Understanding the Interconnected Relationship

BACKGROUND

Human milk oligosaccharides have been shown to relate to the infant gut microbiome. However, the impact of other human milk components on infant gut bacterial colonization remains unexplored.

OBJECTIVES

Our cross-sectional analysis aimed to investigate associations between human milk components (energy, macronutrients, free amino acids, inflammatory markers, and hormones) and infant gut microbiome diversity and composition (phylum, family, and genus) at 6 mo of age.

METHODS

Human milk and infant stool samples were collected at 6 mo postpartum. The infant gut microbiome was profiled using 16S rRNA sequencing. Linear regression models were performed to examine associations, adjusting for pregravid BMI (kg/m2), delivery mode, duration of human milk feeding, and infant sex, with q < 0.2 considered significant.

RESULTS

This analysis included a total of 54 mothers (100% exclusively feeding human milk) and infants (n = 28 male; 51.9%). Total energy in human milk showed a negative association with α-diversity measures (Chao1 and Shannon). Interleukin (IL)-8 in human milk was positively associated with Chao1 and observed operational taxonomic units. At the family level, human milk glutamine and serine levels showed a negative association with the abundance of Veillonellaceae, whereas isoleucine showed a positive association with Bacteroidaceae. Human milk IL-8 and IL-6 concentrations were positively associated with Bacteroidaceae abundance. IL-8 also had a positive relationship with Bifidobacteriaceae, whereas it had a negative relationship with Streptococcacea and Clostridiaceae. Human milk IL-8 was positively associated with the phylum Bacteroidetes, and negatively associated with Proteobacteria. At the genus level, human milk IL-8 exhibited a positive relationship with Bacteroides, whereas human milk isoleucine had a negative relationship with Bacteroides and Ruminococcus. Pregravid BMI and sex effects were observed.

CONCLUSIONS

IL-8 in human milk could potentially prepare the infant's immune system to respond effectively to various microorganisms, potentially promoting the growth of beneficial gut bacteria and protecting against pathogens.

The Impact of Excessive Fructose Intake on Adipose Tissue and the Development of Childhood Obesity

Worldwide, childhood obesity cases continue to rise, and its prevalence is known to increase the risk of non-communicable diseases typically found in adults, such as cardiovascular disease and type 2 diabetes mellitus. Thus, comprehending its multiple causes to build healthier approaches and revert this scenario is urgent. Obesity development is strongly associated with high fructose intake since the excessive consumption of this highly lipogenic sugar leads to white fat accumulation and causes white adipose tissue (WAT) inflammation, oxidative stress, and dysregulated adipokine release. Unfortunately, the global consumption of fructose has increased dramatically in recent years, which is associated with the fact that fructose is not always evident to consumers, as it is commonly added as a sweetener in food and sugar-sweetened beverages (SSB). Therefore, here, we discuss the impact of excessive fructose intake on adipose tissue biology, its contribution to childhood obesity, and current strategies for reducing high fructose and/or free sugar intake. To achieve such reductions, we conclude that it is important that the population has access to reliable information about food ingredients via food labels. Consumers also need scientific education to understand potential health risks to themselves and their children.

Any Infant Formula Amount, but Not Infant Formula Type, Is Associated with Less Healthful Subsequent Beverage Intake among Special Supplemental Nutrition Program for Women, Infants, and Children-Participating Children

Background

The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) provides nutrition assistance to low-income households, including infant formula for infants not fully breastfeeding. Issuance of lactose-reduced infant formula made with corn syrup solids (CSSF) is associated with elevated risk of obesity in early life, but associations between formula type and dietary intake have not been examined.

Objectives

To evaluate associations between infant formula (amount and type) issued by WIC with subsequent child diet at ages 12-59 mo.

Methods

Dietary data from 2014, 2017, and 2020 Los Angeles County WIC Survey respondents (n = 1339 children, 12-59 mo of age) were merged with WIC administrative data on infant feeding (amount and type of infant formula at ages 0-12 mo). Intake frequencies were available for sweetened beverages, sweets, juice, fast food, water, fruit, vegetables, and milk. Infant feeding was categorized by amount of WIC-issued formula (descending: fully formula fed, mostly formula fed, mostly breastfed, fully breastfed) and issuance of a CSSF (any, none). Associations between infant feeding (infant formula amount and type) and child diet were evaluated in multivariable generalized estimating equation negative binomial regression models, stratified by child age (12 to <24 mo, 24 to <60 mo).

Results

Any infant formula issuance in the first year of life was adversely associated with subsequent dietary intake. This included 21%-23% higher 100% juice intake at 24 to <60 mo and 11%-13% (at 24 to <60 mo) or 20%-22% (at 12 to <24 mo) lower water intake. CSSF receipt compared with only other infant formula was not consistently associated with subsequent child diet.

Conclusions

Any infant formula amount, but not CSSF receipt compared with other formula types, was associated with less healthful beverage intake patterns among WIC-participating children. WIC nutrition education may have a stronger impact if tailored based on infant feeding practices.

Altered Nutrient Composition of Lactose-Reduced Infant Formula

This research comprehensively examines 88 infant formulas available in the US market, with an emphasis on their diverging nutritional attributes based on lactose content. We stratified formulas into three categories: lactose-free, lactose-reduced, and entirely lactose-based. The formulas' nutritional content for 58 nutrients was obtained from the Nutrition Data System for Research (NDSR). Nutritional analysis revealed significant differences in nutrient composition across formula categories. For example, the results showed significant associations between the lactose content and glycemic index (GI) of the formula as well as 25 other nutrients. Specifically, we showed that for every gram of lactose per 100 g of formula that is removed, there was a 10.1% increase in GI (β = -10.12, p ≤ 0.000), a 19%,5%, and a 2% increase in added sugar (β = -0.19, p < 0.01), protein (β = -0.05, p < 0.001), and polyunsaturated fatty acids (β = -0.01, p < 0.01). The substitution of lactose in infant formulas significantly alters their nutritional profile, inducing changes in GI, added sugar, protein, and polyunsaturated fatty acids. These modifications have potential consequences for infant growth and metabolic responses and could influence long-term health trajectories. The clinical relevance of the composition differences between formulas should be further explored.

Metatranscriptomic Analyses Reveal Important Roles of the Gut Microbiome in Primate Dietary Adaptation

The gut microbiome plays a vital role in host ecological adaptation, especially dietary adaptations. Primates have evolved a variety of dietary and gut physiological structures that are useful to explore the role of the gut microbiome in host dietary adaptations. Here, we characterize gut microbiome transcriptional activity in ten fecal samples from primates with three different diets and compare the results to their previously reported metagenomic profile. Bacteria related to cellulose degradation, like Bacteroidaceae and Alcaligenaceae, were enriched and actively expressed in the gut microbiome of folivorous primates, and functional analysis revealed that the glycan biosynthesis and metabolic pathways were significantly active. In omnivorous primates, Helicobacteraceae, which promote lipid metabolism, were significantly enriched in expression, and activity and xenobiotic biodegradation and metabolism as well as lipid metabolism pathways were significantly active. In frugivorous primates, the abundance and activity of Elusimicrobiaceae, Neisseriaceae, and Succinivibrionaceae, which are associated with digestion of pectin and fructose, were significantly elevated, and the functional pathways involved in the endocrine system were significantly enriched. In conclusion, the gut microbiome contributes to host dietary adaptation by helping hosts digest the inaccessible nutrients in their specific diets.

Protein and carbohydrate content of infant formula purchased in the United States

BACKGROUND

The protein and carbohydrate composition of formula fed infants' diets in the United States (US) has not been described. The aims of this study were to characterize these dietary exposures in infant formula purchased in the US and to estimate the proportion of formula purchased which is hypoallergenic or lactose-reduced formula.

METHODS

Powdered infant formula purchase data from all major physical stores in the US prior to the COVID-19 pandemic, between 2017 and 2019, were obtained from Information Resources, Inc. Protein and carbohydrate composition and scoop sizes for each formula were obtained from manufacturers. Ready to feed liquid products, products for premature infants and products for over 1 year old were not included.

RESULTS

Total volumes of term formula purchased were 216 million kg of formula powder (equivalent to 1.65 billion litres) over 3 years. Intact protein formula was 67.9% of formula purchased, 26.6% was partially hydrolysed and 5.5% was hypoallergenic (5.2% extensively hydrolysed protein; 0.3% amino acid based). Soy protein formula represented 5.1% of formula purchased. Carbohydrate content overall was 52.7% lactose, 42.3% glucose polymers and 5.0% sucrose. 23.7% of formula purchased included sucrose as a carbohydrate. Of all formula purchased, 59.0% was lactose reduced, containing a non-lactose carbohydrate. Of 'standard' formula, defined as intact protein, non-thickened, cow's milk formula, 32.3% was lactose reduced. The proportion of hypoallergenic formula purchased significantly exceeded the prevalence of cow's milk protein allergy and increased over the 3-year study period from 4.9% to 7.6% of all formula sold.

CONCLUSIONS

US infants are exposed to unnecessarily high levels of non-lactose carbohydrates and hypoallergenic formula, and this may represent a significant nutritional health risk.

Lycopene Affects Intestinal Barrier Function and the Gut Microbiota in Weaned Piglets via Antioxidant Signaling Regulation

BACKGROUND

In pig production, early and abrupt weaning frequently causes weaning stress, which manifests as oxidative damage, barrier disruption, and digestion and absorption capacity declines. Lycopene exhibits beneficial antioxidant capacity in both humans and other animal models.

OBJECTIVES

The present study aimed to investigate the effects of lycopene supplementation on early weaning stress in piglets and the underlying mechanisms by examining the oxidative stress state, gut intestinal barrier function, and the gut microbiota.

METHODS

Twenty-four 21-day-old weaned piglets [Duroc × (Landrace × Yorkshire); castrated males; 5.48 ± 0.10 kg initial body weight] were randomly assigned to 2 treatments. The piglets were fed a basal diet (control treatment) or a basal diet supplemented with 50 mg/kg lycopene (lycopene treatment) for 28 days. The serum lipid levels, serum and jejunum enzyme activities, jejunum morphology, mRNA and protein expression, and gut microbiota were determined.

RESULTS

Compared with the control treatment, lycopene supplementation increased the serum catalase activity (P = 0.042; 62.0%); serum total cholesterol concentration (P = 0.020; 14.1%); and jejunum superoxide dismutase activity (P = 0.032; 21.4%), whereas it decreased serum (P = 0.039, 23.0%) and jejunum (P = 0.047; 20.9%) hydrogen peroxide concentrations. Additionally, lycopene increased the mRNA and protein expression of NFE2-like bZIP transcription factor 2 (214.0% and 102.4%, respectively) and CD36 (100.8% and 145.2%, respectively) in the jejunum, whereas it decreased the mRNA and protein expression of Kelch-like ECH-associated protein 1 (55.6% and 39.8%, respectively ). Lycopene also improved jejunal morphology, increasing the villus height (P = 0.018; 27.5%) and villus:crypt ratio (P < 0.001; 57.9%). Furthermore, it increased the abundances of potentially beneficial bacterial groups, including Phascolarctobacterium and Parasutterella, and decreased those of potentially pathogenic bacterial groups, including Treponema_2 and Prevotellaceae_unclassified.

CONCLUSIONS

Lycopene supplementation strengthens the intestinal barrier function and improves the gut microbiota in weaned piglets by regulating intestinal antioxidant signaling.

Human Milk Oligosaccharide Utilization in Intestinal Bifidobacteria Is Governed by Global Transcriptional Regulator NagR

Bifidobacterium longum subsp. infantis is a prevalent beneficial bacterium that colonizes the human neonatal gut and is uniquely adapted to efficiently use human milk oligosaccharides (HMOs) as a carbon and energy source. Multiple studies have focused on characterizing the elements of HMO utilization machinery in B. longum subsp. infantis; however, the regulatory mechanisms governing the expression of these catabolic pathways remain poorly understood. A bioinformatic regulon reconstruction approach used in this study implicated NagR, a transcription factor from the ROK family, as a negative global regulator of gene clusters encoding lacto-N-biose/galacto-N-biose (LNB/GNB), lacto-N-tetraose (LNT), and lacto-N-neotetraose (LNnT) utilization pathways in B. longum subsp. infantis. This conjecture was corroborated by transcriptome profiling upon nagR genetic inactivation and experimental assessment of binding of recombinant NagR to predicted DNA operators. The latter approach also implicated N-acetylglucosamine (GlcNAc), a universal intermediate of LNT and LNnT catabolism, and its phosphorylated derivatives as plausible NagR transcriptional effectors. Reconstruction of NagR regulons in various Bifidobacterium lineages revealed multiple potential regulon expansion events, suggesting evolution from a local regulator of GlcNAc catabolism in ancestral bifidobacteria to a global regulator controlling the utilization of mixtures of GlcNAc-containing host glycans in B. longum subsp. infantis and Bifidobacterium bifidum. IMPORTANCE The predominance of bifidobacteria in the gut of breastfed infants is attributed to the ability of these bacteria to metabolize human milk oligosaccharides (HMOs). Thus, individual HMOs such as lacto-N-tetraose (LNT) and lacto-N-neotetraose (LNnT) are considered promising prebiotics that would stimulate the growth of bifidobacteria and confer multiple health benefits to preterm and malnourished children suffering from impaired (stunted) gut microbiota development. However, the rational selection of HMO-based prebiotics is hampered by the incomplete knowledge of regulatory mechanisms governing HMO utilization in target bifidobacteria. This study describes NagR-mediated transcriptional regulation of LNT and LNnT utilization in Bifidobacterium longum subsp. infantis. The elucidated regulatory network appears optimally adapted to simultaneous utilization of multiple HMOs, providing a rationale to add HMO mixtures (rather than individual components) to infant formulas. The study also provides insights into the evolutionary trajectories of complex regulatory networks controlling carbohydrate metabolism in bifidobacteria.

Lactose-reduced infant formula with corn syrup solids and obesity risk among participants in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC)

BACKGROUND

The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), a federal nutrition assistance program supporting low-income families, serves half of United States-born infants, most of whom are issued infant formula by age 2 mo. Obesity prevalence is high among children of low-income households, particularly formula-fed children.

OBJECTIVES

This study was conducted to determine whether glucose-based lactose-reduced infant formula made with corn syrup solids (CSSF) is associated with increased obesity risk compared with non-CSSFs that are lactose based.

DESIGN

WIC administrative data on infant formula issuance and child weights and lengths were collected prospectively in Southern California between 2012 and 2020. Included children stopped breastfeeding by 3 mo, were issued cow's milk-based formula through 12 mo, and were enrolled through the final year of WIC eligibility at age 4 y ( n = 15,246). CSSF issuance was assessed continuously (range 0-13 mo) and dichotomously (any, none). Poisson and linear risk regression with robust SE estimates generated risk ratios (RRs), risk differences, and CIs for child obesity [BMI for age (in kg/m 2) ≥95th percentile].

RESULTS

Any CSSF was issued to 23% of children, and 25% were obese at age 4 y. Children with any CSSF issuance had 10% higher obesity risk (RR: 1.10; 95% CI: 1.02, 1.20) than children with no CSSF issuance at age 2 y. Associations remained significant through age 4 y (RR: 1.07; 95% CI: 1.01,1.14), independent of maternal weight status, total formula issued and breastfeeding duration, and were not modified by child race or sex. Obesity risk increased with additional mo of CSSF exposure, reaching 16% higher risk (RR: 1.16; 95% CI: 1.05, 1.28) at age 2 y for children with 12 mo of CSSF.

CONCLUSIONS

CSSF issuance is associated with increased obesity risk in the first 5 y life in a dose dependent manner, independently of maternal weight status, breastfeeding duration, and total formula issuance.

Milk glycan metabolism by intestinal bifidobacteria: insights from comparative genomics

Bifidobacteria are early colonizers of the human neonatal gut and provide multiple health benefits to the infant, including inhibiting the growth of enteropathogens and modulating the immune system. Certain Bifidobacterium species prevail in the gut of breastfed infants due to the ability of these microorganisms to selectively forage glycans present in human milk, specifically human milk oligosaccharides (HMOs) and N-linked glycans. Therefore, these carbohydrates serve as promising prebiotic dietary supplements to stimulate the growth of bifidobacteria in the guts of children suffering from impaired gut microbiota development. However, the rational formulation of milk glycan-based prebiotics requires a detailed understanding of how bifidobacteria metabolize these carbohydrates. Accumulating biochemical and genomic data suggest that HMO and N-glycan assimilation abilities vary remarkably within the Bifidobacterium genus, both at the species and strain levels. This review focuses on the delineation and genome-based comparative analysis of differences in respective biochemical pathways, transport systems, and associated transcriptional regulatory networks, providing a foundation for genomics-based projection of milk glycan utilization capabilities across a rapidly growing number of sequenced bifidobacterial genomes and metagenomic datasets. This analysis also highlights remaining knowledge gaps and suggests directions for future studies to optimize the formulation of milk-glycan-based prebiotics that target bifidobacteria.

High fat diet-induced hyperlipidemia and tissue steatosis in rabbits through modulating ileal microbiota

High-fat diet (HFD) and overnutrition are important starting factors that may alter intestinal microbiota, lipid metabolism, and systemic inflammation. However, there were few studies on how intestinal microbiota contributes to tissue steatosis and hyperlipidemia. Here, we investigated the effect of lipid metabolism disorder-induced inflammation via toll-like receptor 2 (TLR-2), toll-like receptor 4 (TLR-4), and nuclear factor-κB (NF-κB) pathways at the intestinal level in response to HFD. Twenty 80-day-old male New Zealand White rabbits were randomly divided into the normal diet group (NDG) and the high-fat diet group (HDG) for 80 days. Growth performance, blood biochemical parameters, lipid metabolism, inflammation, degree of tissue steatosis, and intestinal microbial composition were measured. HFD increased the relative abundance of Christensenellaceae_R_7_group, Marvinbryantia, Akkermansia etc., with a reduced relative abundance of Enterorhabdus and Lactobacillus. Moreover, HFD caused steatosis in the liver and abdominal fat and abnormal expression of some genes related to lipid metabolism and tight junction proteins. The TLR-2, TLR-4, NF-κB, TNF-α, and IL-6 were confirmed by overexpression with downregulation of IL-10. Serum biochemical indices (TG, TCHO, LDL-C, and HDL-C) were also increased, indicating evidence for the development of the hyperlipidemia model. Correlation analysis showed that this microbial dysbiosis was correlated with lipid metabolism and inflammation, which were associated with the intestinal tract's barrier function and hyperlipidemia. These results provide an insight into the relationship between HFD, the intestinal microbiota, intestinal barrier, tissue inflammation, lipid metabolism, and hyperlipidemia. KEY POINTS: • High-fat diet leads to ileal microbiota disorders • Ileal microbiota mediates local and systemic lipid metabolism disorders and inflammation • There is a specific link between ileal microbiota, histopathology, and hyperlipidemia.

Feeding mode influences dynamic gut microbiota signatures and affects susceptibility to anti-CD3 mAb-induced intestinal injury in neonatal mice

Feeding modes influence the gut microbiome, immune system, and intestinal barrier homeostasis in neonates; how feeding modes impact susceptibility to neonatal gastrointestinal (GI) diseases is still uncertain. Here, we investigated the impact of dam feeding (DF) and formula feeding (FF) on features of the gut microbiome and physiological inflammation during the first 2 days of postnatal development and on the susceptibility to intestinal injury related to the inflammatory state in neonatal mouse pups. 16S rRNA sequencing data revealed microbiome changes, lower α-diversity, and a distinct pattern of β-diversity including expansion of f_Enterobacteriaceae and f_Enterococcaceae in the ileum of FF pups compared with DF pups by postnatal day (P)2. Together with gut dysbiosis, the FF cohort also had greater ileal mucosa physiological inflammatory activity compared with DF pups by P2 but maintained normal histological features. Interestingly, FF but not DF mouse pups developed necrotizing enterocolitis (NEC)-like intestinal injury within 24 h after anti-CD3 mAb treatment, suggesting that FF influences the susceptibility to intestinal injury in neonates. We further found that NEC-like incidence in anti-CD3 mAb-treated FF neonatal pups was attenuated by antibiotic treatment. Collectively, our data suggest that FF predisposes mouse pups to anti-CD3 mAb-induced intestinal injury due to abnormal f_Enterobacteriaceae and f_Enterococcaceae colonization. These findings advance our understanding of FF-associated microbial colonization and intestinal inflammation, which may help inform the development of new therapeutic approaches to GI diseases like NEC in infants.NEW & NOTEWORTHY This report shows that a feeding mode profoundly affects gut colonization in neonatal mice. Furthermore, our results demonstrate that formula feeding predisposes mouse pups to anti-CD3 mAb-induced necrotizing enterocolitis (NEC)-like intestinal injury upon inadequate microbial colonization. The study suggests the role of the combined presence of formula feeding-associated dysbiosis and mucosal inflammation in the pathogenesis of NEC and provides a new mouse model to study this disease.

Adverse Effects of Infant Formula Made with Corn-Syrup Solids on the Development of Eating Behaviors in Hispanic Children

Few studies have investigated the influence of infant formulas made with added corn-syrup solids on the development of child eating behaviors. We examined associations of breastmilk (BM), traditional formula (TF), and formula containing corn-syrup solids (CSSF) with changes in eating behaviors over a period of 2 years. Feeding type was assessed at 6 months in 115 mother−infant pairs. Eating behaviors were assessed at 12, 18 and 24 months. Repeated Measures ANCOVA was used to determine changes in eating behaviors over time as a function of feeding type. Food fussiness and enjoyment of food differed between the feeding groups (p < 0.05) and changed over time for CSSF and TF (p < 0.01). Food fussiness increased from 12 to 18 and 12 to 24 months for CSSF and from 12 to 24 months for TF (p < 0.01), while it remained stable for BM. Enjoyment of food decreased from 12 to 24 months for CSSF (p < 0.01), while it remained stable for TF and BM. There was an interaction between feeding type and time for food fussiness and enjoyment of food (p < 0.01). Our findings suggest that Hispanic infants consuming CSSF may develop greater food fussiness and reduced enjoyment of food in the first 2 years of life compared to BM-fed infants.

Integrated Microbiomic and Metabolomic Dynamics of Fermented Corn and Soybean By-Product Mixed Substrate

Microbes and their metabolites produced in fermented food have been considered as critical contributors to the quality of the final products, but the comprehensive understanding of the microbiomic and metabolomic dynamics in plant-based food during solid-state fermentation remains unclear. Here, the probiotics of Bacillus subtilis and Enterococcus faecalis were inoculated into corn and defatted soybean to achieve the two-stage solid-state fermentation. A 16S sequencing and liquid chromatography–tandem mass spectrometry were applied to investigate the dynamics of microbiota, metabolites, and their integrated correlations during fermentation. The results showed that the predominant bacteria changed from Streptophyta and Rickettsiales at 0 h to Bacillus and Pseudomonas in aerobic stage and then to Bacillus, Enterococcus, and Pseudomonas in anaerobic stage. In total, 229 notably different metabolites were identified at different fermentation times, and protein degradation, amino acid synthesis, and carbohydrate metabolism were the main metabolic pathways during the fermentation. Notably, phenylalanine metabolism was the most important metabolic pathway in the fermentation process. Further analysis of the correlations among the microbiota, metabolites, and physicochemical characteristics indicated that Bacillus spp. was significantly correlated with amino acids and carbohydrate metabolism in aerobic stage, and Enterococcus spp. was remarkably associated with amino acids metabolism and lactic acid production in the anaerobic stage. The present study provides new insights into the dynamic changes in the metabolism underlying the metabolic and microbial profiles at different fermentation stages, and are expected to be useful for future studies on the quality of fermented plant-based food.

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.

Binary Metabolic Phenotypes and Phenotype Diversity Metrics for the Functional Characterization of Microbial Communities

The profiling of 16S rRNA revolutionized the exploration of microbiomes, allowing to describe community composition by enumerating relevant taxa and their abundances. However, taxonomic profiles alone lack interpretability in terms of bacterial metabolism, and their translation into functional characteristics of microbiomes is a challenging task. This bottom-up approach minimally requires a reference collection of major metabolic traits deduced from the complete genomes of individual organisms, an accurate method of projecting these traits from a reference collection to the analyzed amplicon sequence variants (ASVs), and, ultimately, an approach to a microbiome-wide aggregation of predicted individual traits into physiologically relevant cumulative metrics to characterize and compare multiple microbiome samples. In this study, we extended a previously introduced computational approach for the functional profiling of complex microbial communities, which is based on the concept of binary metabolic phenotypes encoding the presence ("1") or absence ("0") of various measurable physiological properties in individual organisms that are termed phenotype carriers or non-carriers, respectively. Derived from complete genomes via metabolic reconstruction, binary phenotypes provide a foundation for the prediction of functional traits for each ASV identified in a microbiome sample. Here, we introduced three distinct mapping schemes for a microbiome-wide phenotype prediction and assessed their accuracy on the 16S datasets of mock bacterial communities representing human gut microbiome (HGM) as well as on two large HGM datasets, the American Gut Project and the UK twins study. The 16S sequence-based scheme yielded a more accurate phenotype predictions, while the taxonomy-based schemes demonstrated a reasonable performance to warrant their application for other types of input data (e.g., from shotgun metagenomics or qPCR). In addition to the abundance-weighted Community Phenotype Indices (CPIs) reflecting the fractional representation of various phenotype carriers in microbiome samples, we employ metrics capturing the diversity of phenotype carriers, Phenotype Alpha Diversity (PAD) and Phenotype Beta Diversity (PBD). In combination with CPI, PAD allows to classify the robustness of metabolic phenotypes by their anticipated stability in the face of potential environmental perturbations. PBD provides a promising approach for detecting the metabolic features potentially contributing to disease-associated metabolic traits as illustrated by a comparative analysis of HGM samples from healthy and Crohn's disease cohorts.

The Relationship Between Breast Milk Components and the Infant Gut Microbiota

The assembly of the newborn's gut microbiota during the first months of life is an orchestrated process resulting in specialized microbial ecosystems in the different gut compartments. This process is highly dependent upon environmental factors, and many evidences suggest that early bacterial gut colonization has long-term consequences on host digestive and immune homeostasis but also metabolism and behavior. The early life period is therefore a "window of opportunity" to program health through microbiota modulation. However, the implementation of this promising strategy requires an in-depth understanding of the mechanisms governing gut microbiota assembly. Breastfeeding has been associated with a healthy microbiota in infants. Human milk is a complex food matrix, with numerous components that potentially influence the infant microbiota composition, either by enhancing specific bacteria growth or by limiting the growth of others. The objective of this review is to describe human milk composition and to discuss the established or purported roles of human milk components upon gut microbiota establishment. Finally, the impact of maternal diet on human milk composition is reviewed to assess how maternal diet could be a simple and efficient approach to shape the infant gut microbiota.

Metabolic Phenotypes as Potential Biomarkers for Linking Gut Microbiome With Inflammatory Bowel Diseases

The gut microbiome is of utmost importance to human health. While a healthy microbiome can be represented by a variety of structures, its functional capacity appears to be more important. Gene content of the community can be assessed by “shotgun” metagenomics, but this approach is still too expensive. High-throughput amplicon-based surveys are a method of choice for large-scale surveys of links between microbiome, diseases, and diet, but the algorithms for predicting functional composition need to be improved to achieve good precision. Here we show how feature engineering based on microbial phenotypes, an advanced method for functional prediction from 16S rRNA sequencing data, improves identification of alterations of the gut microbiome linked to the disease. We processed a large collection of published gut microbial datasets of inflammatory bowel disease (IBD) patients to derive their community phenotype indices (CPI)—high-precision semiquantitative profiles aggregating metabolic potential of the community members based on genome-wide metabolic reconstructions. The list of selected metabolic functions included metabolism of short-chain fatty acids, vitamins, and carbohydrates. The machine-learning approach based on microbial phenotypes allows us to distinguish the microbiome profiles of healthy controls from patients with Crohn's disease and from ones with ulcerative colitis. The classifiers were comparable in quality to conventional taxonomy-based classifiers but provided new findings giving insights into possible mechanisms of pathogenesis. Feature-wise partial dependence plot (PDP) analysis of contribution to the classification result revealed a diversity of patterns. These observations suggest a constructive basis for defining functional homeostasis of the healthy human gut microbiome. The developed features are promising interpretable candidate biomarkers for assessing microbiome contribution to disease risk for the purposes of personalized medicine and clinical trials.