Characterisation and validation of lactation information from structured electronic health records for use in pharmacoepidemiological studies.

BACKGROUND: Breastfeeding information stored within electronic health records (EHR) has recently been used for pharmacoepidemiological research, however the data are primarily collected for clinical care. OBJECTIVES: To characterise breastfeeding information recorded in structured fields in EHR during infant and postpartum health care visits, and to assess the validity of lactation status based on EHR data versus maternal report at research study visits. METHODS: We assessed breastfeeding information recorded in structured fields in EHR from one health system for a subset of 211 patients who were also enrolled in a study on breast milk composition between 2014 and 2017 that required participants to exclusively breastfeed their infants until at least 1 month of age. We assessed the frequency of breastfeeding information in EHR during the first 12 months of age and compared lactation status based on EHR with maternal report at 1 and 6-month study visits (reference standard). RESULTS: The median number of breastfeeding records in the EHR per infant was six (interquartile range 3) with most observations clustering in the first few weeks of life and around well-infant visits. At the 6-month study visit, 93.8% of participants were breastfeeding and 80.1% were exclusively breastfeeding according to maternal report. Sensitivity of EHR data for identifying ever breastfeeding was at or near 100%, and sensitivity for identifying ever exclusive breastfeeding was 98.0% (95% CI: 95.0%, 99.2%). Sensitivities were 97.3% (95% CI: 93.9%, 98.9%) for identifying any breastfeeding and 94.4% (95% CI: 89.7%, 97.0%) for exclusive breastfeeding, and positive predictive values were 99.5% (95% CI: 97.0%, 99.9%) for any breastfeeding and 95.0% (95% CI: 90.4%, 97.4%) for exclusive breastfeeding. CONCLUSIONS: Breastfeeding information in structured EHR fields have the potential to accurately classify lactation status. The validity of these data should be assessed in populations with a lower breastfeeding prevalence.

Hidden: A Baker's Dozen Ways in Which Research Reporting is Less Transparent than it Could be and Suggestions for Implementing Einstein's Dictum.

The tutelage of our mentors as scientists included the analogy that writing a good scientific paper was an exercise in storytelling that omitted unessential details that did not move the story forward or that detracted from the overall message. However, the advice to not get lost in the details had an important flaw. In science, it is the many details of the data themselves and the methods used to generate and analyze them that give conclusions their probative meaning. Facts may sometimes slow or distract from the clarity, tidiness, intrigue, or flow of the narrative, but nevertheless they are important for the assessment of what was done, the trustworthiness of the science, and the meaning of the findings. Nevertheless, many critical elements and facts about research studies may be omitted from the narrative and become hidden from scholarly scrutiny. We describe a "baker's dozen" shortfalls in which such elements that are pertinent to evaluating the validity of scientific studies are sometimes hidden in reports of the work. Such shortfalls may be intentional or unintentional or lie somewhere in between. Additionally, shortfalls may occur at the level of the individual or an institution or of the entire system itself. We conclude by proposing countermeasures to these shortfalls.

Stability of Human-Milk Oligosaccharide Concentrations Over 1 Week of Lactation and Over 6 Hours Following a Standard Meal.

BACKGROUND: Our previous studies revealed that human-milk oligosaccharides (HMOs) have health benefits for nursing infants and their concentrations change dynamically over 24 mo of lactation. Yet, the extent to which HMOs vary over the short term (days) and in response to acute factors such as maternal diet is unclear. OBJECTIVE: The purpose of this study was to determine the stability of HMO concentrations over 7 d and in response to a standard meal and sugar-sweetened beverage (SSB) over 6 h. METHODS: In this ancillary study, lactating mothers were enrolled at 6 wk postpartum. Participants received in-person instructions and materials to complete procedures at home. In the 1-wk experiment (n = 11), mothers pumped a milk sample at 07:00 h for 7 consecutive days. In the 6-h experiment (n = 35), mothers pumped a milk sample after an overnight fast at 06:00 h and then consumed a standard meal plus SSB provided by the study team. Mothers pumped a milk sample every hour for 6 consecutive hours. Samples were analyzed for the 19 most abundant HMOs. Repeated-measures ANOVA was used to test changes in HMO concentrations over time, reported as F(dftime, dferror) = F value, P value. RESULTS: Concentrations of all assayed HMOs were stable over 7 consecutive days, including, for example, the most widely studied HMOs in relation to infant health: 2'-fucosyllactose (2'FL) [F(2,17) = 0.39, P = 0.65], disialyl-lacto-N-tetraose (DSLNT) [F(4, 37) = 0.60, P = 0.66], and lacto-N-neotetraose (LNnT) [F(3, 32) = 1.5, P = 0.23]. Concentrations of all assayed HMOs were stable in response to a standard meal plus SSB. For example, fasted baseline concentrations of 2'FL, DSLNT, and LNnT were 2310 ± 1620 µg/mL, 560 ± 290 µg/mL, and 630 ± 290 µg/mL, respectively, and there were no changes in 2'FL [F(4, 119) = 1.9, P = 0.13], DSLNT [F(4, 136) = 0.39, P = 0.83], and LNnT [F(4, 120) = 0.64, P = 0.63] over 6 consecutive hours. CONCLUSIONS: HMO concentrations are stable over 1 wk of lactation and are not acutely affected by a standard meal plus SSB in mothers.

Bone Mass Accrual in First Six Months of Life: Impact of Maternal Diabetes, Infant Adiposity, and Cord Blood Adipokines.

The perinatal period is a time of substantial bone mass accrual with many factors affecting long-term bone mineralization. Currently it is unclear what effect maternal gestational/type 2 diabetes has on infant bone mass accrual. This is a prospective study of offspring of Native American and Hispanic mothers with normoglycemia (n = 94) and gestational diabetes or type 2 diabetes (n = 64). Infant anthropometrics were measured at birth, 1, and 6 months of age. Cord blood leptin, high-molecular weight adiponectin (HMWA), pigment epithelium-derived factor (PEDF), vascular epithelium growth factor (VEGF), endoglin, and C-peptide were measured by ELISA. Infants had bone mineral density measurement at 1 month or/and 6 months of age using dual-energy x-ray absorptiometry scan. Mothers with diabetes were older (31 ± 6 years vs 25 ± 4 years) and had higher pre-pregnancy BMI (32.6 ± 5.8 vs 27.2 ± 6.4 kg/m2) than control mothers. Mean HbA1C of mothers with diabetes was 5.9 ± 1.0% compared to 5.1 ± 0.3% in controls early in pregnancy. Infants born to mothers with diabetes (DM-O) were born at a slightly lower gestational age compared to infants born to control mothers (Con-O). There was no difference in total body less head bone mineral content (BMC) or bone mineral density (BMD) between DM-O and Con-O. For both groups together, bone area, BMD, and BMC tracked over the first 6 months of life (r: 0.56, 0.38, and 0.48, respectively). Percent fat was strongly and positively correlated with BMC at 1 month of age (r = 0.44; p < 0.001) and BMC at both 1 and 6 months of age correlated strongly with birth weight. There were no associations between infant bone mass and cord blood leptin, PEDF, or VEGF, while C-peptide had a significant correlation with BMC at 1 and 6 months only in DM-O (p = 0.01 and 0.03, respectively). Infants born to mothers with well-controlled gestational/type 2 diabetes have normal bone mass accrual. Bone mineral content during this time is highly correlated with indices of infant growth and the association of bone mineral indices with percent body fat suggests that bone-fat crosstalk is operative early in life.

Maternal Dietary Intake of Total Fat, Saturated Fat, and Added Sugar Is Associated with Infant Adiposity and Weight Status at 6 mo of Age.

BACKGROUND: Whether current dietary guidelines are appropriate for pregnancy and lactation has not been well studied. Many women of reproductive age are not meeting recommendations for dietary components such as fat, added sugar, and fiber. OBJECTIVES: To assess associations between maternal dietary components during pregnancy and lactation and infant growth and adiposity at 6 mo of age. METHODS: Mother-infant dyads (n = 349) from the prospective, observational Mothers and Infants Linked for Healthy Growth study were included (100% fully breastfed for 1 mo; 75% to 6 mo). Daily intake of fat, fiber, and added sugar was obtained using the National Cancer Institute Diet History Questionnaire II during the third trimester of pregnancy and at 1 and 3 mo postpartum. Furthermore, intakes were categorized as meeting/exceeding 2015-2020 Dietary Guidelines for Americans. Multiple linear regression models adjusted for numerous potential confounders tested relations between dietary components and infant adiposity (via DXA) and growth parameters. Regression coefficients (ß) for continuous variables were expressed per SD to allow for comparison of effect sizes. RESULTS: Maternal intake of total fat and saturated fat was positively associated with infant percent body fat (%BF) (ß: 0.84 per SD, P = 0.04; ß: 0.96 per SD, P = 0.01, respectively). Added sugar intake was positively associated with infant weight-for-length z score (ß: 0.16 per SD, P = 0.02), and excessive added sugar intake was positively associated with %BF at 6 mo (ß: 0.75 per SD, P = 0.05). CONCLUSIONS: In a predominantly fully breastfeeding cohort of women, maternal intake of fat and added sugar during pregnancy and lactation were associated with small increases in infant adiposity and relative weight at 6 mo. Additional research is needed to determine if these relations persist later in infancy and if such elevations in adiposity are important for long-term obesity risk.

Infant sex differences in human milk intake and composition from 1- to 3-month post-delivery in a healthy United States cohort.

BACKGROUND: Macronutrient composition of human milk differs by infant sex, but few studies have examined sex differences in other milk components, or their potential modification by maternal body mass index (BMI). AIM: We compared milk intake and human milk hormone and cytokine concentrations at 1- and 3-month post-delivery and tested infant sex by maternal BMI (OW/OB vs. NW) interactions. SUBJECTS AND METHOD: Data were analysed for 346 mother-infant dyads in the Mothers and Infants Linked for Healthy Growth (MILk) Study at 1- and 3-month post-delivery. Infant milk intake was estimated by the change in infant weight after test feedings. Concentrations of glucose, insulin, leptin, adiponectin, interleukin-6 (IL-6), and C-reactive protein (CRP) were measured using ELISA. Multivariable linear regression and linear mixed models were used to estimate sex main effects and their interaction with maternal BMI. RESULTS: Mean glucose concentration at 1 month was 2.62 mg/dl higher for male infants, but no difference at 3 months was observed. Milk intake and concentrations for the other milk components were similar for males and females at both time points. Associations with infant sex did not differ significantly by maternal BMI. CONCLUSIONS: Among healthy United States mother-infant dyads, appetite, and growth-regulating factors in human milk did not differ significantly by infant sex.

Associations of breastfeeding or formula feeding with infant anthropometry and body composition at 6 months.

The objective of this study was to investigate the associations of mode of feeding with infant anthropometric and body composition variables at 6 months of age. We studied 259 infants whose exclusive mode of feeding (breast or formula) to 1 month was confirmed. Standard anthropometric characteristics of the infants (weight, length and weight-for-length z scores) were obtained, and body composition (total fat mass, fat-free mass, trunk fat mass and body fat percent) was measured using dual-energy X-ray absorptiometry (DXA) at 6 months (±12 days). General linear models were used to test the associations of mode of feeding with infant anthropometric and body composition variables at 6 months after adjustment for maternal and infant covariates. In this cohort of predominantly breastfed, White infants of highly educated mothers, fat-free mass was lower (P = .002), and trunk fat mass (P = .032) and body fat percent (P < .001) were greater in breastfed infants than in formula-fed infants at 6 months of age. After adjustment for covariates, total fat-free mass was significantly lower (ß = -372 g, [SE = 125, P = .003]), and body fat percent was significantly greater (ß = 3.30, [SE = 0.91, P < .001]) in breastfed infants than in formula-fed infants. No other significant associations were observed. These findings support those of previous studies reporting greater fat-free mass in formula-fed infants during the first 6 months of life. Additional research is warranted to explore whether differences in infant body composition by mode of feeding persist throughout the life course and to assess causality.

Carbohydrate composition in breast milk and its effect on infant health.

PURPOSE OF REVIEW: This narrative review presents the current state of available evidence regarding the role of breast milk carbohydrates on infant outcomes, with a primary focus on growth and body composition. RECENT FINDINGS: To date, there is a paucity of available data that exists in this realm. The current literature focuses on the role of two carbohydrate fractions in breast milk, and their relationships with infant outcomes in the first six months of life: oligosaccharides and fructose. A small but growing body of research indicates robust associations of both oligosaccharides and fructose in breast milk with infant weight and length, as well as bone, fat, and lean mass. There is also emerging evidence to support the role of these same carbohydrate fractions in breast milk in infant cognitive development. SUMMARY: The present state of the science suggests that oligosaccharides and fructose in breast milk play a role in infant growth and body composition and introduces intriguing associations of these two carbohydrate fractions with infant cognitive development as well.

Body Mass Index Is a Better Indicator of Body Composition than Weight-for-Length at Age 1 Month.

OBJECTIVE: To assess whether body mass index (BMI) provides a better assessment of measured adiposity at age 1 month compared with weight-for-length (WFL). STUDY DESIGN: Participants were healthy term-born infants in the Infant Growth and Microbiome (n = 146) and the Baby Peas (n = 147) studies. Length, weight, and body composition by air displacement plethysmography were measured at 1 month. World Health Organization-based WFL and BMI z-scores were calculated. Within-cohort z-scores of percent fat-Z, fat mass-Z, fat mass/length2-Z, fat mass/length3-Z, fat-free mass-Z, and fat-free mass/length2-Z were calculated. Correlation and multiple linear regression (adjusted for birth weight) analyses tested the associations between body composition outcomes and BMI-Z vs WFL-Z. Quantile regression was used to test the stability of these associations across the distribution of body compositions. RESULTS: The sample was 52% female and 56% African American. Accounting for birth weight, both BMI-Z and WFL-Z were strongly associated with fat mass-Z (coefficients 0.56 and 0.35, respectively), FM/L2-Z (0.73 and 0.51), and FM/L3-Z (0.79 and 0.58), with stronger associations for BMI-Z compared with WFL-Z (P < .05). Even after accounting statistically for birth weight, BMI-Z was persistently more strongly associated than WFL-Z with body composition outcomes across the distribution of body composition outcomes. CONCLUSIONS: We demonstrate in 2 distinct cohorts that BMI is a better indicator of adiposity in early infancy compared with WFL. Our findings support the preferred use of BMI for growth and nutritional status assessment in infancy.

Pharmacokinetics of Sucralose and Acesulfame-Potassium in Breast Milk Following Ingestion of Diet Soda.

OBJECTIVE: The aim of this study was to determine sucralose and acesulfame-potassium (ace-K) pharmacokinetics in breast milk following maternal ingestion of a diet soda. METHODS: Thirty-four exclusively breast-feeding women (14 normal-weight, 20 obese) consumed 12 ounces of Diet Rite Cola, sweetened with 68-mg sucralose and 41-mg ace-K, before a standardized breakfast meal. Habitual non-nutritional sweeteners intake was assessed via a diet questionnaire. Breast milk was collected from the same breast before beverage ingestion and hourly for 6 hours. RESULTS: Owing to one mother having extremely high concentrations, peak sucralose and acesulfame-potassium concentrations following ingestion of diet soda ranged from 4.0 to 7387.9 ng/mL (median peak 8.1 ng/mL) and 299.0 to 4764.2 ng/mL (median peak 945.3 ng/mL), respectively. CONCLUSIONS: Ace-K and sucralose transfer into breast milk following ingestion of a diet soda. Future research should measure concentrations after repeated exposure and determine whether chronic ingestion of sucralose and acesulfame-potassium via the breast milk has clinically relevant health consequences.

Suitability of Bioelectrical Based Methods to Assess Water Compartments in Recreational and Elite Athletes.

OBJECTIVE: It is important for highly active individuals to easily and accurately assess their hydration level. Bioelectrical impedance (BIA) can potentially meet these needs but its validity in active individuals is not well established. We aim to validate total body water (TBW), extracellular water (ECW), and intracellular water (ICW) estimates obtained from 50 kHz BIA, bioelectrical impedance spectroscopy (BIS), and BIA-based models against dilution techniques in 2 populations: active adults and elite athletes. METHODS: Active males (N = 28, 20-39 years) involved in recreational sports and elite athletes (females: N = 57, 16-35 years; males: N = 127, 16-38 years) participated in this study. TBW and ECW were assessed with deuterium and bromide dilution, respectively. ICW was assessed as their difference. Body water compartments were also assessed by BIA (BIA-101), BIS (model 4200), and BIA-based equations. RESULTS: Small but significant differences were observed between alternative methods and the criterion in all subsamples. In female athletes, r(2) > 0.69, r(2) > 0.57, and r(2) > 0.65 were observed between methods in the TBW, ECW, and ICW estimates. In males, r(2) > 0.75, r(2) > 0.65, and r(2) > 0.68 were found between alternative and reference methods in the TBW, ECW, and ICW estimates, respectively, whereas for male recreational exercisers, r(2) > 0.58, r(2) > 0.73, and r(2) > 0.75 were observed. Pure errors ranged between 0.19 to 3.32 kg for TBW, 0.64 to 1.63 for ECW, and 1.98 to 2.64 in ICW. The highest limits of agreement (LoA) were observed in Van Loan and Mayclin equation and the BIA method, respectively, for TBW and ECW assessment and the lowest LoA were observed in BIS for both TBW and ECW estimates. CONCLUSIONS: The higher accuracy of BIS in predicting individual TBW, ECW, and ICW highlights its utility in water assessment of recreational and elite athletes.

Lower resting energy expenditure and fat oxidation in Native American and Hispanic infants born to mothers with diabetes.

OBJECTIVE: To determine whether exposure to diabetes in utero affects resting energy expenditure (REE) and fuel oxidation in infants. STUDY DESIGN: At 35 ± 5 days after birth, body composition and REE were measured in full-term offspring of Native American and Hispanic women with either well-controlled diabetes (13 girls, 11 boys) or normal healthy pregnancies (18 girls, 17 boys). RESULTS: Control of dysglycemia during gestation in the women with diabetes mellitus met current clinical standards, shown by average glycated hemoglobin (5.9 ± 0.2%; 40.6 ± 2.3 mmol/mol). Infant body mass (offspring of women with diabetes: 4.78 ± 0.13, control offspring: 4.56 ± 0.08 kg) and body fatness (offspring of women with diabetes: 25.2 ± 0.6, control offspring: 24.2 ± 0.5 %) did not differ between groups. REE, adjusted for lean body mass, was 14% lower in offspring of women with diabetes (41.7 ± 2.3 kJ/h) than control offspring (48.6 ± 2.0, P = .025). Fat oxidation was 26% lower in offspring of women with diabetes (0.54 ± 0.05 g/h) than control offspring (0.76 ± 0.04, P < .01) but carbohydrate oxidation did not differ. Thus, fat oxidation accounted for a lower fraction of REE in the offspring of women with diabetes (49 ± 4%) than control offspring (60 ± 3%, P = .022). Mothers with diabetes were older and had higher prepregnancy body mass index than control mothers. CONCLUSIONS: Well-controlled maternal diabetes did not significantly affect body mass or composition of offspring at 1-month old. However, infants with mothers with diabetes had reduced REE and fat oxidation, which could contribute to adiposity and future disease risk. Further studies are needed to assess the impact differences in age and higher prepregnancy body mass index.

Packet randomized experiments for eliminating classes of confounders.

BACKGROUND: Although randomization is considered essential for causal inference, it is often not possible to randomize in nutrition and obesity research. To address this, we develop a framework for an experimental design-packet randomized experiments (PREs), which improves causal inferences when randomization on a single treatment variable is not possible. This situation arises when subjects are randomly assigned to a condition (such as a new roommate) which varies in one characteristic of interest (such as weight), but also varies across many others. There has been no general discussion of this experimental design, including its strengths, limitations, and statistical properties. As such, researchers are left to develop and apply PREs on an ad hoc basis, limiting its potential to improve causal inferences among nutrition and obesity researchers. METHODS: We introduce PREs as an intermediary design between randomized controlled trials and observational studies. We review previous research that used the PRE design and describe its application in obesity-related research, including random roommate assignments, heterochronic parabiosis, and the quasi-random assignment of subjects to geographic areas. We then provide a statistical framework to control for potential packet-level confounders not accounted for by randomization. RESULTS: Packet randomized experiments have successfully been used to improve causal estimates of the effect of roommates, altitude, and breastfeeding on weight outcomes. When certain assumptions are met, PREs can asymptotically control for packet-level characteristics. This has the potential to statistically estimate the effect of a single treatment even when randomization to a single treatment did not occur. CONCLUSIONS: Applying PREs to obesity-related research will improve decisions about clinical, public health, and policy actions insofar as it offers researchers new insight into cause and effect relationships among variables.

Cord blood adipokines, neonatal anthropometrics and postnatal growth in offspring of Hispanic and Native American women with diabetes mellitus.

BACKGROUND: Offspring of women with diabetes mellitus (DM) during pregnancy have a risk of developing metabolic disease in adulthood greater than that conferred by genetics alone. The mechanisms responsible are unknown, but likely involve fetal exposure to the in utero milieu, including glucose and circulating adipokines. The purpose of this study was to assess the impact of maternal DM on fetal adipokines and anthropometry in infants of Hispanic and Native American women. METHODS: We conducted a prospective study of offspring of mothers with normoglycemia (Con-O; n = 79) or type 2 or gestational DM (DM-O; n = 45) pregnancies. Infant anthropometrics were measured at birth and 1-month of age. Cord leptin, high-molecular-weight adiponectin (HMWA), pigment epithelium-derived factor (PEDF) and C-peptide were measured by ELISA. Differences between groups were assessed using the Generalized Linear Model framework. Correlations were calculated as standardized regression coefficients and adjusted for significant covariates. RESULTS: DM-O were heavier at birth than Con-O (3.7 ± 0.6 vs. 3.4 ± 0.4 kg, p = 0.024), but sum of skinfolds (SSF) were not different. At 1-month, there was no difference in weight, SSF or % body fat or postnatal growth between groups. Leptin was higher in DM-O (20.1 ± 14.9 vs. 9.5 ± 9.9 ng/ml in Con-O, p < 0.0001). Leptin was positively associated with birth weight (p = 0.0007) and SSF (p = 0.002) in Con-O and with maternal hemoglobin A1c in both groups (Con-O, p = 0.023; DM-O, p = 0.006). PEDF was positively associated with birth weight in all infants (p = 0.004). Leptin was positively associated with PEDF in both groups, with a stronger correlation in DM-O (p = 0.009). At 1-month, HMWA was positively associated with body weight (p = 0.004), SSF (p = 0.025) and % body fat (p = 0.004) across the cohort. CONCLUSIONS: Maternal DM results in fetal hyperleptinemia independent of adiposity. HMWA appears to influence postnatal growth. Thus, in utero exposure to DM imparts hormonal differences on infants even without aberrant growth.

Weighing the Evidence of Common Beliefs in Obesity Research.

Obesity is a topic on which many views are strongly held in the absence of scientific evidence to support those views, and some views are strongly held despite evidence to contradict those views. We refer to the former as "presumptions" and the latter as "myths." Here, we present nine myths and 10 presumptions surrounding the effects of rapid weight loss; setting realistic goals in weight loss therapy; stage of change or readiness to lose weight; physical education classes; breastfeeding; daily self-weighing; genetic contribution to obesity; the "Freshman 15"; food deserts; regularly eating (versus skipping) breakfast; eating close to bedtime; eating more fruits and vegetables; weight cycling (i.e., yo-yo dieting); snacking; built environment; reducing screen time in childhood obesity; portion size; participation in family mealtime; and drinking water as a means of weight loss. For each of these, we describe the belief and present evidence that the belief is widely held or stated, reasons to support the conjecture that the belief might be true, evidence to directly support or refute the belief, and findings from randomized controlled trials, if available. We conclude with a discussion of the implications of these determinations, conjecture on why so many myths and presumptions exist, and suggestions for limiting the spread of these and other unsubstantiated beliefs about the obesity domain.

Adequacy of Infant Formula With Protein Content of 1.6 g/100 kcal for Infants Between 3 and 12 Months.

OBJECTIVES: Infant formulas provide more protein than breast milk. High protein intakes may place infants at risk of later obesity. The present study tested whether a formula with protein content below the regulatory level supports normal growth from age 3 months. METHODS: Randomized double-blind trial enrolled healthy infants less than age 3 months. At 3 months, formula-fed infants were assigned to experimental (EXPL, 1.61 g protein/100 kcal; modified bovine whey proteins with caseinoglycomacropeptide removed) or control (CTRL 2.15 g protein/100 kcal; unmodified bovine milk protein with a whey/casein ratio of 60/40) formula; breast-fed (BF) infants were enrolled in a reference group. Complementary foods were allowed in small amounts from 4 to 6 months and unrestricted after 6 months. RESULTS: Weight gain (g/day) from 3 to 6 months was similar in the EXPL and CTRL groups (EXPL-CTRL -0.84 g/day; 95% confidence interval -2.25 to 0.57) and faster in the EXPL and CTRL groups than in the BF group. Weight analyzed longitudinally from 4 to 12 months was lower in the EXPL group than in the CTRL group (P = 0.031) but higher than in the BF group (P < 0.0001). Longitudinal analysis of odds ratios from 4 to 12 months indicated fewer infants with weight >85th percentile in the EXPL group than in the CTRL group (P = 0.015). Length z scores were lower than, and body mass index z scores were similar to, World Health Organization Standards in all of the groups. Serum biochemical parameters in the EXPL group reflected lower protein intake and were closer to parameters in the BF infants than in the CTRL group. CONCLUSIONS: A formula with 1.61 g of protein/100 kcal supports normal growth of infants after age 3 months. This protein content is adequate if provided from a high-quality source.

Body composition assessment in the infant.

Body composition assessment provides a sharper picture of the human biological response to genetic and environmental influences than measures of body size and weight. Infant body composition is particularly important as a marker of fetal adaptation and developmental programming of subsequent health and disease, but until recently, the range of options for measuring infant body composition was relatively narrow. The purpose of this Toolkit: Methods in Human Biology review is to provide a comprehensive overview of methods of body composition methods currently used in infants 0 to 2 years of age, including anthropometric prediction equations, air displacement plethysmography (ADP), dual energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA), isotope dilution, and magnetic resonance imaging (MRI). Information on the reliability, validity, and accuracy of the methods is provided. Unique aspects of infant physiology and behavior create challenges for body composition assessment, but this review provides guidance on suitable testing approaches and environments that may aid researchers in this important area of investigation.

Assembly, stability, and dynamics of the infant gut microbiome are linked to bacterial strains and functions in mother's milk.

The establishment of the gut microbiome in early life is critical for healthy infant development. Although human milk is recommended as the sole source of nutrition for the human infant, little is known about how variation in milk composition, and especially the milk microbiome, shapes the microbial communities in the infant gut. Here, we quantified the similarity between the maternal milk and the infant gut microbiome using 507 metagenomic samples collected from 195 mother-infant pairs at one, three, and six months postpartum. We found that the microbial taxonomic overlap between milk and the infant gut was driven by bifidobacteria, in particular by B. longum. Infant stool samples dominated by B. longum also showed higher temporal stability compared to samples dominated by other species. We identified two instances of strain sharing between maternal milk and the infant gut, one involving a commensal (B. longum) and one a pathobiont (K. pneumoniae). In addition, strain sharing between unrelated infants was higher among infants born at the same hospital compared to infants born in different hospitals, suggesting a potential role of the hospital environment in shaping the infant gut microbiome composition. The infant gut microbiome at one month compared to six months of age was enriched in metabolic pathways associated with de-novo molecule biosynthesis, suggesting that early colonisers might be more versatile and metabolically independent compared to later colonizers. Lastly, we found a significant overlap in antimicrobial resistance genes carriage between the mother's milk and their infant's gut microbiome. Taken together, our results suggest that the human milk microbiome has an important role in the assembly, composition, and stability of the infant gut microbiome.

Human milk variation is shaped by maternal genetics and impacts the infant gut microbiome.

Human milk is a complex mix of nutritional and bioactive components that provide complete nourishment for the infant. However, we lack a systematic knowledge of the factors shaping milk composition and how milk variation influences infant health. Here, we characterize relationships between maternal genetics, milk gene expression, milk composition, and the infant fecal microbiome in up to 310 exclusively breastfeeding mother-infant pairs. We identified 482 genetic loci associated with milk gene expression unique to the lactating mammary gland and link these loci to breast cancer risk and human milk oligosaccharide concentration. Integrative analyses uncovered connections between milk gene expression and infant gut microbiome, including an association between the expression of inflammation-related genes with milk interleukin-6 (IL-6) concentration and the abundance of Bifidobacterium and Escherichia in the infant gut. Our results show how an improved understanding of the genetics and genomics of human milk connects lactation biology with maternal and infant health.

Maternal oral probiotic use is associated with decreased breastmilk inflammatory markers, infant fecal microbiome variation, and altered recognition memory responses in infants-a pilot observational study.

Introduction: Early life gut microbiomes are important for brain and immune system development in animal models. Probiotic use has been proposed as a strategy to promote health via modulation of microbiomes. In this observational study, we explore if early life exposure to probiotics via the mother during pregnancy and lactation, is associated with decreased inflammation in breastmilk, maternal and infant microbiome variation, and altered infant neurodevelopmental features. Methods: Exclusively breastfeeding mother-infant dyads were recruited as part of the "Mothers and Infants Linked for Healthy Growth (MILk) Study." Probiotic comparison groups were defined by exposure to maternal probiotics (NO/YES) and by timing of probiotic exposure (prenatal, postnatal, total). C-reactive protein (CRP) and IL-6 levels were determined in breastmilk by immunoassays, and microbiomes were characterized from 1-month milk and from 1- and 6-month infant feces by 16S rDNA sequencing. Infant brain function was profiled via electroencephalogram (EEG); we assessed recognition memory using event-related potential (ERP) responses to familiar and novel auditory (1 month) and visual (6 months) stimuli. Statistical comparisons of study outcomes between probiotic groups were performed using permutational analysis of variance (PERMANOVA) (microbiome) and linear models (all other study outcomes), including relevant covariables as indicated. Results: We observed associations between probiotic exposure and lower breastmilk CRP and IL-6 levels, and infant gut microbiome variation at 1- and 6-months of age (including higher abundances of Bifidobacteria and Lactobacillus). In addition, maternal probiotic exposure was associated with differences in infant ERP features at 6-months of age. Specifically, infants who were exposed to postnatal maternal probiotics (between the 1- and 6-month study visits) via breastfeeding/breastmilk, had larger differential responses between familiar and novel visual stimuli with respect to the late slow wave component of the EEG, which may indicate greater memory updating potential. The milk of mothers of this subgroup of infants had lower IL-6 levels and infants had different 6-month fecal microbiomes as compared to those in the "NO" maternal probiotics group. Discussion: These results support continued research into "Microbiota-Gut-Brain" connections during early life and the role of pre- and postnatal probiotics in mothers to promote healthy microbiome-associated outcomes in infants.