Fatty acids are a vital component of human milk. They influence infant neurodevelopment and immune function, and they provide ∼50% of milk–s energy content.
The objectives of this study were to ...characterize the composition of human milk fatty acids in a large Canadian birth cohort and identify factors influencing their variability.
In a subset of the CHILD cohort (n = 1094), we analyzed milk fatty acids at 3–4 mo postpartum using GLC. Individual and total SFAs, MUFAs, and n–3 and n–6 PUFAs were analyzed using SD scores and principal component analysis (PCA). Maternal diet, sociodemographic, health, and environmental factors were self-reported. Single-nucleotide polymorphisms were assessed in the fatty acid desaturase 1 (FADS1-rs174556) and 2 (FADS2-rs174575) genes.
Fatty acid profiles were variable, with individual fatty acid proportions varying from 2- to >30-fold between women. Using PCA, we identified 4 milk fatty acid patterns: “MUFA and low SFA,” “high n–6 PUFA,” “high n–3 PUFA,” and “high medium-chain fatty acids.” In multivariable-adjusted analyses, fish oil supplementation and fatty cold water fish intake were positively associated with DHA and the “high n–3 PUFA” pattern. Mothers carrying the minor allele of FADS1-rs174556 had lower proportions of arachidonic acid (ARA; 20:4n–6). Independent of selected dietary variables and genetic variants, Asian ethnicity was associated with higher linoleic acid (18:2n–6) and total n–3 PUFAs. Ethnic differences in ARA were explained by FADS1 genotype. Maternal obesity was independently associated with higher total SFAs, the “high medium-chain fatty acid” pattern, and lower total MUFAs. Lactation stage, season, study site, and maternal education were also independently associated with some milk fatty acids. No associations were observed for maternal age, parity, delivery mode, or infant sex.
This study provides unique insights about the “normal” variation in the composition of human milk fatty acids and the contributing dietary, genetic, sociodemographic, health, and environmental factors. Further research is required to assess implications for infant health.
Objective To evaluate the association of probiotic supplementation during pregnancy or infancy with childhood asthma and wheeze.Design Systematic review and meta-analysis of randomised controlled ...trials.Data sources Medline, Embase, and Central (Cochrane Library) databases from inception to August 2013, plus the World Health Organization’s international clinical trials registry platform and relevant conference proceedings for the preceding five years. Included trials and relevant reviews were forward searched in Web of Science.Review methods Two reviewers independently identified randomised controlled trials evaluating probiotics administered to mothers during pregnancy or to infants during the first year of life. The primary outcome was doctor diagnosed asthma; secondary outcomes included wheeze and lower respiratory tract infection.Results We identified 20 eligible trials including 4866 children. Trials were heterogeneous in the type and duration of probiotic supplementation, and duration of follow-up. Only five trials conducted follow-up beyond participants’ age of 6 years (median 24 months), and none were powered to detect asthma as the primary outcome. The overall rate of doctor diagnosed asthma was 10.7%; overall rates of incident wheeze and lower respiratory tract infection were 33.3% and 13.9%, respectively. Among 3257 infants enrolled in nine trials contributing asthma data, the risk ratio of doctor diagnosed asthma in participants randomised to receive probiotics was 0.99 (95% confidence interval 0.81 to 1.21, I2=0%). The risk ratio of incident wheeze was 0.97 (0.87 to 1.09, I2=0%, 9 trials, 1949 infants). Among 1364 infants enrolled in six trials, the risk ratio of lower respiratory tract infection after probiotic supplementation was 1.26 (0.99 to 1.61, I2=0%). We adjudicated most trials to be of high (ten trials) or unclear (nine trials) risk of bias, mainly due to attrition.Conclusions We found no evidence to support a protective association between perinatal use of probiotics and doctor diagnosed asthma or childhood wheeze. Randomised controlled trials to date have not yielded sufficient evidence to recommend probiotics for the primary prevention of these disorders. Extended follow-up of existing trials, along with further clinical and basic research, are needed to accurately define the role of probiotics in the prevention of childhood asthma.Systematic review registration PROSPERO (CRD42013004385).
Implications for practice and research Healthcare providers should focus on improving knowledge around breastfeeding guidelines and the benefits of breast feeding for mothers in low socioeconomic ...status (SES) groups. Context Breastfeeding sets the foundation for healthy growth and development, with many recognised benefits for both infant and maternal health. ...socioeconomic disparities in breastfeeding—which are widely reported in the USA and many other Western countries1—contribute significantly to socioeconomic health disparities across the lifespan. Importantly, these factors are modifiable and link directly to three key determinants of health: social support networks, education and access to health services.4 Commentary Kopp et al 2 uniquely report on breastfeeding intentions (rather than rates), which is an under-researched area, particularly among mothers with lower SES.
Studies addressing breastfeeding and obesity rarely document the method of breast milk feeding, type of supplementation, or feeding in hospital. We investigated these practices in the CHILD birth ...cohort.
Feeding was reported by mothers and documented from hospital records. Weight and BMI
scores (BMIzs) were measured at 12 months. Analyses controlled for maternal BMI and other confounders.
Among 2553 mother-infant dyads, 97% initiated breastfeeding, and the median breastfeeding duration was 11.0 months. Most infants (74%) received solids before 6 months. Among "exclusively breastfed" infants, 55% received some expressed breast milk, and 27% briefly received formula in hospital. Compared with exclusive direct breastfeeding at 3 months, all other feeding styles were associated with higher BMIzs: adjusted β: +.12 (95% confidence interval CI: .01 to .23) for some expressed milk, +.28 (95% CI: .16 to .39) for partial breastfeeding, and +.45 (95% CI: .30 to .59) for exclusive formula feeding. Brief formula supplementation in hospital did not alter these associations so long as exclusive breastfeeding was established and sustained for at least 3 months. Formula supplementation by 6 months was associated with higher BMIzs (adjusted β: +.25; 95% CI: .13 to .38), whereas supplementation with solid foods was not. Results were similar for weight gain velocity.
Breastfeeding is inversely associated with weight gain velocity and BMI. These associations are dose dependent, partially diminished when breast milk is fed from a bottle, and substantially weakened by formula supplementation after the neonatal period.
The incidence of pediatric asthma has increased substantially in recent decades, reaching a worldwide prevalence of 14%. This rapid increase may be attributed to the loss of "Old Friend" microbes ...from the human microbiota resulting in a less diverse and "dysbiotic" gut microbiota, which fails to optimally stimulate immune development during infancy. This hypothesis is supported by observations that the gut microbiota is different in infants who develop asthma later in life compared to those who remain healthy. Thus, early life exposures that influence gut microbiota play a crucial role in asthma development. Breastfeeding is one such exposure; it is generally considered protective against pediatric asthma, although conflicting results have been reported, potentially due to variations in milk composition between individuals and across populations. Human milk oligosaccharides (HMOs) and milk microbiota are two major milk components that influence the infant gut microbiota and hence, development of the immune system. Among their many immunomodulatory functions, HMOs exert a selective pressure within the infant gut microbial niche, preferentially promoting the proliferation of specific bacteria including
. Milk is also a source of viable bacteria originating from the maternal gut and infant oral cavity. As such, breastmilk has prebiotic and probiotic properties that can modulate two of the main forces controlling the gut microbial community assembly, i.e., dispersal and selection. Here, we review the latest evidence, mechanisms and hypotheses for the synergistic and/or additive effects of milk microbiota and HMOs in protecting against pediatric asthma.
Human milk is a complex and dynamic biological system that has evolved to optimally nourish and protect human infants. Yet, according to a recent priority-setting review, "our current understanding ...of human milk composition and its individual components and their functions fails to fully recognize the importance of the chronobiology and systems biology of human milk in the context of milk synthesis, optimal timing and duration of feeding, and period of lactation" (P. Christian et al., Am J Clin Nutr 113:1063-1072, 2021, https://doi.org/10.1093/ajcn/nqab075). We attribute this critical knowledge gap to three major reasons as follows. (i) Studies have typically examined each subsystem of the mother-milk-infant "triad" in isolation and often focus on a single element or component (e.g., maternal lactation physiology or milk microbiome or milk oligosaccharides or infant microbiome or infant gut physiology). This undermines our ability to develop comprehensive representations of the interactions between these elements and study their response to external perturbations. (ii) Multiomics studies are often cross-sectional, presenting a snapshot of milk composition, largely ignoring the temporal variability during lactation. The lack of temporal resolution precludes the characterization and inference of robust interactions between the dynamic subsystems of the triad. (iii) We lack computational methods to represent and decipher the complex ecosystem of the mother-milk-infant triad and its environment. In this review, we advocate for longitudinal multiomics data collection and demonstrate how incorporating knowledge gleaned from microbial community ecology and computational methods developed for microbiome research can serve as an anchor to advance the study of human milk and its many components as a "system within a system."
PURPOSE OF REVIEWBy replacing sugar, nonnutritive sweeteners (NNSs) are thought to aid in weight management and decrease insulin resistance. We reviewed the latest randomized clinical trials (RCTs) ...investigating the effects NNSs on glycaemic control.
RECENT FINDINGSSix RCTs addressed this topic between 2017 and 2018; the majority tested artificial NNS (sucralose or aspartame), with only one testing natural NNS (stevia and monk fruit extract). Most found no effect of NNS on blood glucose, insulin, gastric inhibitory polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) levels; however, two trials showed an effect of sucralose on the acute insulin response.
SUMMARYWe are still incapable of reaching a definite judgement on which types of NNS, if any, impact glycaemic control. There is a need for more research to overcome the limitations of recent RCTs, related to sample size, intervention duration, dose, form of NNSs used, and inclusion of males or female participants only. Future studies should also compare different NNS types with each other, and include the increasingly popular ‘natural’ NNS.
Allergic disease is the most frequent chronic health issue in children and has been linked to early-life gut microbiome dysbiosis. Many lines of evidence suggest that microbially derived short-chain ...fatty acids, and particularly butyrate, can promote immune tolerance.
We sought to determine whether bacterial butyrate production in the gut during early infancy is protective against the development of atopic disease in children.
We used shotgun metagenomic analysis to determine whether dysbiosis in butyrate fermentation could be identified in human infants, before their developing allergic disease.
We found that the microbiome of infants who went on to develop allergic sensitization later in childhood lacked genes encoding key enzymes for carbohydrate breakdown and butyrate production.
Our findings support the importance of microbial carbohydrate metabolism during early infancy in protecting against the development of allergies.
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IMPORTANCE: The effect of neonatal and infant feeding practices on childhood obesity is unclear. The gut microbiome is strongly influenced by feeding practices and has been linked to obesity. ...OBJECTIVE: To characterize the association between breastfeeding, microbiota, and risk of overweight during infancy, accounting for the type and timing of supplementary feeding. DESIGN, SETTING, AND PARTICIPANTS: In this study of a subset of 1087 infants from the prospective CHILD pregnancy cohort, mothers were recruited between January 1, 2009, and December 31, 2012. Statistical analysis was performed from February 1 to December 20, 2017. MAIN OUTCOMES AND MEASURES: Feeding was reported by mothers and documented from hospital records. Fecal microbiota at 3 to 4 months (from 996 infants) and/or 12 months (from 821 infants) were characterized by 16S ribosomal RNA sequencing. Infants with a weight for length exceeding the 85th percentile were considered to be at risk for overweight. RESULTS: There were 1087 infants in the study (507 girls and 580 boys); at 3 months, 579 of 1077 (53.8%) were exclusively breastfed according to maternal report. Infants who were exclusively formula fed at 3 months had an increased risk of overweight in covariate-adjusted models (53 of 159 33.3% vs 74 of 386 19.2%; adjusted odds ratio, 2.04; 95% CI, 1.25-3.32). This association was attenuated (adjusted odds ratio, 1.33; 95% CI, 0.79-2.24) after further adjustment for microbiota features characteristic of formula feeding at 3 to 4 months, including higher overall richness and enrichment of Lachnospiraceae. A total of 179 of 579 infants who were exclusively breastfed (30.9%) received formula as neonates; this brief supplementation was associated with lower relative abundance of Bifidobacteriaceae and higher relative abundance of Enterobacteriaceae at 3 to 4 months but did not influence the risk of overweight. At 12 months, microbiota profiles differed significantly according to feeding practices at 6 months; among partially breastfed infants, formula supplementation was associated with a profile similar to that of nonbreastfed infants (higher diversity and enrichment of Bacteroidaceae), whereas the introduction of complementary foods without formula was associated with a profile more similar to that of exclusively breastfed infants (lower diversity and enrichment of Bifidobacteriaceae and Veillonellaceae). Microbiota profiles at 3 months were more strongly associated with risk of overweight than were microbiota profiles at 12 months. CONCLUSIONS AND RELEVANCE: Breastfeeding may be protective against overweight, and gut microbiota may contribute to this effect. Formula feeding appears to stimulate changes in microbiota that are associated with overweight, whereas other complementary foods do not. Subtle microbiota differences emerge after brief exposure to formula in the hospital. These results identify important areas for future research and distinguish early infancy as a critical period when transient gut dysbiosis may lead to increased risk of overweight.
Multiple studies have demonstrated that early-life exposure to pets or siblings affords protection against allergic disease; these associations are commonly attributed to the "hygiene hypothesis". ...Recently, low diversity of the infant gut microbiota has also been linked to allergic disease. In this study, we characterize the infant gut microbiota in relation to pets and siblings.
The study population comprised a small sub-sample of 24 healthy, full term infants from the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort. Mothers reported on household pets and siblings. Fecal samples were collected at 4 months of age, and microbiota composition was characterized by high-throughput signature gene sequencing.
Microbiota richness and diversity tended to be increased in infants living with pets, whereas these measures were decreased in infants with older siblings. Infants living with pets exhibited under-representation of Bifidobacteriaceae and over-representation of Peptostreptococcaceae; infants with older siblings exhibited under-representation of Peptostreptococcaceae.
This study provides new evidence that exposure to pets and siblings may influence the early development of the gut microbiota, with potential implications for allergic disease. These two traditionally protective "hygiene hypothesis" factors appear to differentially impact gut microbiota composition and diversity, calling into question the clinical significance of these measures. Further research is required to confirm and expand these findings.
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