Babies fed breastmilk by breast versus by bottle: a pilot study evaluating early growth patterns

Comparison of the Effect of Direct Breastfeeding, Expressed Human Milk, and Infant Formula Feeding on Infant Weight Trajectories: A Systematic Review

Background: Formula and breastfeeding are known factors associated with infant weight trajectories. Evidence exploring the effect of expressed human milk feeding on infant weight in the community setting has not been well synthesized. Objectives: This systematic review examined (1) weight changes among infants fed expressed human milk and (2) differences in weight change between infants fed expressed human milk and infants fed at the breast or infant formula via bottle. Methods: A comprehensive search of the literature was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The quality of each study was appraised using the Joanna Briggs Critical Appraisal Tools. Results: A total of six studies met the eligibility criteria and included a total of 5,152 infants. The within-subject analysis identified only 31 infants strictly or predominantly fed expressed human milk. The between-subject analysis comparing expressed human milk feeding to the available comparison groups (formula-fed or direct at the breastfed) revealed that higher weight gains were observed in the weight trajectories among infants in the bottle or formula-fed conditions in four of the six included studies. Conclusions: Findings from the few studies included in this review found a difference in the infant weight gain patterns among expressed human milk-fed infants when compared with their respective feeding groups (directly breastfed or formula-fed). Further research is needed to corroborate these findings and elucidate the clinical significance of the differences in weight gain patterns observed across infant feeding groups.

Association of Infant Feeding Methods and Excess Weight from Birth to Age 6

Objective: To examine the associations between human milk feeding method (at the breast versus bottle) and measures of child adiposity during the first 6 years of life. Study Design: Women 12 months' postpartum who delivered a singleton, liveborn infant at >24 weeks gestation completed a survey assessing infant feeding methods and sociodemographics. Mothers were recontacted when the child was 6 years old for a follow-up study assessing growth (N = 269). Children were categorized as ever or never having excess weight using weight-for-age z-scores (WAZ), weight-for-height z-scores (WHZ), and body mass index-for-age z-scores (BMIZ) from birth to 6 years. Modified Poisson regression estimated associations between the duration of each feeding method (exclusive and combined) with excess weight status. Mixed-effect models estimated associations between feeding methods and trajectories of the outcomes. Results: For all feeding practices, increasing duration (in months) was unassociated with the risk of ever having excess weight by age 6 years. Based on mixed models, longer duration of feeding human milk by any method was associated with lower BMIZ (adj β for 6-12 months versus 0-3 months = -0.50, 95% CI: -0.99 to -0.01) and also with the shape of the BMIZ trajectory curve. No other associations between feeding methods and excess weight outcomes were observed. Conclusions: Longer duration of feeding human milk was associated with lower average BMIZ in early childhood but feeding at the breast and feeding expressed milk were not clearly associated with the outcomes when considered separately. Larger studies would help clarify the associations between these specific feeding methods and outcomes. IRB17-00876.

Exclusivity of breastfeeding and body composition: learnings from the Baby-bod study

Background

This report evaluated the breastfeeding status in a Tasmanian cohort and its effects on infant and maternal anthropometry and body composition.

Methods

An observational-cohort analysis of self-reported feeding data from 175 Tasmanian mother-baby dyads (recruited via in-person contact between September 2017 and October 2019), was executed. Only mothers who were ≥ 18 years of age, who had a singleton pregnancy and were able to speak and understand English, were included in the study. Infants outside a gestational age range between 37^+ 0 and 41^+ 6 weeks were excluded. Infant (using Air Displacement Plethysmography) and maternal body composition was assessed at 0, 3 and 6 months. Analysis of variance with relevant statistical corrections were utilised for cross-sectional and longitudinal comparisons between non-exclusively breastfed (neBF) and exclusively breastfed (eBF) groups.

Results

Fat-free mass was significantly higher [t = 2.27, df = 98, P = 0.03, confidence interval (CI) 0.03, 0.48] in neBF infants at 6 months (5.59 ± 0.59 vs 5.33 ± 0.50 kg) despite a higher mean fat-free mass in eBF infants at birth (2.89 ± 0.34 vs 3.01 ± 0.35 kg). Weak evidence for different fat mass index trajectories was observed for eBF and neBF infants in the first 6 months of life (ANOVA, F = 2.42, df = 1.9, P = 0.09) with an inversion in fat mass index levels between 3 and 6 months. Body Mass Index (BMI) trajectories were significantly different in eBF and neBF mothers through pregnancy and the first 6 months postpartum (ANOVA, F = 5.56, df = 30.14, P = 0.01). Compared with eBF mothers, neBF mothers retained significantly less weight (t = − 2.754, df = 158, P = 0.02, CI -6.64, − 1.09) at 3 months (0.68 ± 11.69 vs 4.55 ± 6.08 kg) postpartum. Prevalence for neBF was incrementally higher in mothers with a normal BMI compared to mothers with obesity, and mothers who underwent surgical or medical intervention during birth were less likely to exclusively breastfeed.

Conclusions

Infants with different feeding patterns may display varying growth patterns in early life and sustained breastfeeding can contribute to greater postpartum maternal weight loss.

Mixed milk feeding: a systematic review and meta-analysis of its prevalence and drivers

CONTEXT

Extensive literature is available on exclusive breastfeeding and formula-feeding practices and health effects. In contrast, limited and unstructured literature exists on mixed milk feeding (MMF), here defined as the combination of breastfeeding and formula feeding during the same period in term infants > 72 hours old (inclusion criterion).

OBJECTIVE

A systematic review and meta-analysis were performed, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, on the global prevalence of MMF (primary outcome) and related drivers and practices (secondary outcomes).

DATA SOURCES

The search of MMF in generally healthy populations was conducted across 6 databases, restricted to publications from January 2000 to August 2018 in English, Spanish, French, and Mandarin.

DATA EXTRACTION

Two reviewers independently performed screenings and data extraction according to a priori inclusion and exclusion criteria.

DATA ANALYSIS

Of the 2931 abstracts identified, 151 full-text publications were included for data extraction and 96 of those were included for data synthesis (the majority of those were cross-sectional and cohort studies). The authors summarized data across 5 different categories (feeding intention prenatally, and 4 age intervals between > 72 hours and > 6-23 months) and 5 regional subgroups. The overall prevalence of MMF across different age intervals and regions varied between 23% and 32%; the highest rate was found for the age group 4-6 months (32%; 95% confidence interval, 27%-38%); regional comparisons indicated highest MMF rates in Asia (34%), North and South America (33%), and Middle East and Africa together (36%), using a random effects meta-analysis model for proportions. Some drivers and practices for MMF were identified.

CONCLUSION

MMF is a widespread feeding reality. A shared and aligned definition of MMF will help shed light on this feeding practice and evaluate its influence on the duration of total breastfeeding, as well as on infants' nutrition status, growth, development, and health status in the short and long terms. PROSPERO registration number CRD42018105337.

Improved Estimation of Breastfeeding Rates Using a Novel Breastfeeding and Milk Expression Survey

Background: Increasing the proportion of infants who are breastfed and extending breastfeeding duration are high-priority U.S. goals. Evaluation of progress is based on federal survey data, but federal survey questions do not reflect contemporary feeding practices. Materials and Methods: Our objective was to evaluate the Brief Breastfeeding and Milk Expression Recall Survey (BaByMERS) in estimating breast milk feeding and milk expression practices and compare to estimates from simultaneously administered federal survey questions. We surveyed women with child(ren) younger than the age of 6 years attending a large children's hospital for urgent or primary care. We estimated the proportions who participated in various breast milk feeding and milk expression practices and the durations of each and examined agreement between the surveys. We compared respondents with high versus low disagreement using log-binomial regression. Results: Of 225 respondents, 51% had less than a Bachelor's degree, and 44% identified as a race other than white. Similar proportions on each survey reported ever having breastfed or fed breast milk (84%). Proportions still breastfeeding or feeding breast milk at 6 and 12 months differed slightly by survey. Dyads (9%) who fed at the breast and fed expressed milk for nonidentical periods had estimates for the duration of breastfeeding or feeding breast milk that were lower per the federal survey. Respondents who answered the federal survey before the BaByMERS were more likely to provide discrepant responses (risk ratio = 3.40, 95% confidence interval: 1.18-9.80). Conclusions: This study offers further validation of brief interviewer-administered questions to collect quality data recalled about infant feeding and lactation for research purposes.

Comparing Alternative Breast Milk Feeding Questions to U.S. Breastfeeding Surveillance Questions

Background: Most mothers in the United States express their milk, which is then bottle fed to their infants. The National Immunization Survey (NIS), used to report national breastfeeding prevalence, asks about infant breast milk consumption, regardless of whether it is consumed at the mother's breast or from a bottle. The NIS data are often erroneously interpreted, however, to mean prevalence of at-the-breast feeding. We hypothesized that over half of infants classified as breastfed at 3, 6, and 12 months by the NIS questions would also be consuming expressed breast milk. Materials and Methods: A convenience sample of 456 mothers of infants 19-35 months of age recruited through ResearchMatch.org completed an online infant-feeding questionnaire. The questionnaire included both the NIS questions and more-detailed questions about feeding mode, distinguishing between at-the-breast and bottle. Results: Based on responses of our sample to the NIS questions, it could be interpreted that 74%, 64%, and 39% of mother-infant dyads were at-the-breast feeding at 3, 6, and 12 months, respectively. However, at each time point, most infants consumed at least some breast milk from a bottle. As infants got older, the proportion of breast milk consumed from a bottle increased. Conclusions: In this U.S. sample, the predominant breast milk feeding style involves both at-the-breast and expressed breast milk feeding. Future research and national surveillance should consider including separate measures of maternal breast milk expression and infant consumption of expressed breast milk to enable meaningful exploration of maternal and infant outcomes associated with these asynchronous behaviors.

Latent trajectories of infant breast milk consumption in the United States

Patterns of breastfeeding over time are not currently well understood. Limited qualitative and quantitative evidence suggests that there may be latent subgroups of mothers in the United States following very different trajectories of breast milk provision for their infants. This study used a quantitative modelling method (group-based trajectory modelling) to identify and describe these subgroups. Using data from the Infant Feeding Practices Study II (n = 3,023), the authors identified four distinct trajectories of breastfeeding intensity, each of which included a substantial subset of the total sample. A model with four groups fit the data well by objective and conceptual standards. Bivariate associations were analysed, and significant difference between trajectory group membership was found on an array of maternal and family determinants, including maternal demographics, hospital experience, and psychosocial resources, as well as on postweaning perceptions. These associations were used to create group profiles for each subgroup. Controlling for sociodemographic covariates, we also found that trajectory membership was significantly associated with several health outcomes for the target child 6 years later, including certain infections, picky eating, and health care utilization; trajectory group membership was also associated with maternal breastfeeding of subsequent children and maternal body mass index (BMI) at Year 6. Child BMI z-score and maternal breast cancer diagnosis were not significantly different across trajectory groups after accounting for confounding covariates, nor was time missed from school for the target child. Though exploratory, the initial identification and description of these four subgroups suggest future directions using breastfeeding trajectory methods, with potential implications for measurement, intervention development, and targeting.

Human Milk Casein and Whey Protein and Infant Body Composition over the First 12 Months of Lactation

Human milk (HM) influences infant feeding patterns and body composition (BC). This small proof-of concept longitudinal study investigated relationships between infant/maternal BC and HM casein, whey and total protein during the first 12 months of lactation. BC of breastfeeding dyads (n = 20) was measured at 2 (n = 15), 5 (n = 20), 9 (n = 19), and/or 12 (n = 18) months postpartum with ultrasound skinfolds (infants) and bioimpedance spectroscopy (infants/mothers). Proteins concentrations and 24-h milk intake were measured and calculated daily intakes (CDI) determined. Higher maternal weight, body mass index, fat-free mass, fat-free mass index, and fat mass index were associated with higher concentration of whey protein (p ≤ 0.034, n = 20). There were no associations between infant BC and concentrations of all proteins, and CDI of whey and total protein. Higher CDI of casein were associated with lower infant fat-free mass (p = 0.003, n = 18) and higher fat mass (p < 0.001), fat mass index (p = 0.001, n = 18), and % fat mass (p < 0.001, n = 18) measured with ultrasound skinfolds. These results show a differential effect of HM casein on development of infant BC during the first year of life, suggesting that there is a potential to improve outcome for the infant through interventions, such as continuation of breastfeeding during the first 12 months of life and beyond, which may facilitate favourable developmental programming that could reduce risk of non-communicable diseases later in life.

Human Milk Adiponectin and Leptin and Infant Body Composition over the First 12 Months of Lactation

Human milk (HM) adipokines may influence infant feeding patterns, appetite regulation, and body composition (BC). The associations between concentrations/calculated daily intakes (CDI) of HM adipokines in the first 12 months postpartum and maternal/term infant BC, and infant breastfeeding parameters were investigated. BC of breastfeeding dyads (n = 20) was measured at 2, 5, 9, and/or 12 months postpartum with ultrasound skinfolds (infants) and bioimpedance spectroscopy (infants/mothers). 24-h milk intake and feeding frequency were measured along with whole milk adiponectin and skim and whole milk leptin (SML and WML) and CDI were calculated. Statistical analysis used linear regression/mixed effects models; results were adjusted for multiple comparisons. Adipokine concentrations did not associate with infant BC. Higher CDI of adiponectin were associated with lower infant fat-free mass (FFM; p = 0.005) and FFM index (FFMI; p = 0.009) and higher fat mass (FM; p < 0.001), FM index (FMI; p < 0.001), and %FM (p < 0.001). Higher CDI of SML were associated with higher infant FM (p < 0.001), FMI (p < 0.001), and %FM (p = 0.002). At 12 months, higher CDI of WML were associated with larger increases in infant adiposity (2–12 month: FM, p = 0.0006; %FM, p = 0.0004); higher CDI of SML were associated with a larger decrease in FFMI (5–12 months: p = 0.0004). Intakes of HM adipokines differentially influence development of infant BC in the first year of life, which is a critical window of infant programming and may potentially influence risk of later disease via modulation of BC.

Air displacement plethysmography (pea pod) in full-term and pre-term infants: a comprehensive review of accuracy, reproducibility, and practical challenges

Air displacement plethysmography (ADP) has been widely utilised to track body composition because it is considered to be practical, reliable, and valid. Pea Pod is the infant version of ADP that accommodates infants up to the age of 6 months and has been widely utilised to assess the body composition of full-term infants, and more recently pre-term infants. The primary goal of this comprehensive review is to 1) discuss the accuracy/reproducibility of Pea Pod in both full- and pre-term infants, 2) highlight and discuss practical challenges and potential sources of measurement errors in relation to Pea Pod operating principles, and 3) make suggestions for future research direction to overcome the identified limitations.

Relationships between Breastfeeding Patterns and Maternal and Infant Body Composition over the First 12 Months of Lactation

Breastfeeding has been implicated in the establishment of infant appetite regulation, feeding patterns and body composition (BC). A holistic approach is required to elucidate relationships between infant and maternal BC and contributing factors, such as breastfeeding parameters. Associations between maternal and breastfed term infant BC (n = 20) and feeding parameters during first 12 months of lactation were investigated. BC was measured at 2, 5, 9 and/or 12 months postpartum with ultrasound skinfolds (US; infants only) and bioimpedance spectroscopy (infants and mothers). 24-h milk intake (MI) and feeding frequency (FFQ) were measured. Higher FFQ was associated with larger 24-h MI (p ≤ 0.003). Higher 24-h MI was associated with larger infant fat mass (FM) (US: p ≤ 0.002), greater percentage FM (US: p ≤ 0.008), greater FM index (FMI) (US: p ≤ 0.001) and lower fat-free mass index (FFMI) (US: p = 0.015). Lower FFQ was associated with both larger FFM (US: p ≤ 0.001) and FFMI (US: p < 0.001). Greater maternal adiposity was associated with smaller infant FFM measured with US (BMI: p < 0.010; %FM: p = 0.004; FMI: p < 0.011). Maternal BC was not associated with FFQ or 24-h MI. These results reinforce that early life is a critical window for infant programming and that breastfeeding may influence risk of later disease via modulation of BC.

Developmental Trajectories of Bottle-Feeding During Infancy and Their Association with Weight Gain

OBJECTIVE

To describe patterns of bottle-feeding across the first year postpartum and explore whether bottle-feeding trajectories are differentially associated with infant weight gain.

METHOD

Data came from 1291 mothers who participated in the Infant Feeding Practices Study 2. Mothers completed a prenatal questionnaire and monthly surveys of infant feeding and growth between birth and 12 months. Group-based trajectory mixture modeling was used to describe developmental trajectories of bottle-feeding intensities across the first year. Growth curve modeling was used to explore associations between bottle-feeding intensity trajectory group membership and weight-for-age z-score (WAZ) trajectories from birth to 12 months.

RESULTS

Four qualitatively distinct trajectories of bottle-feeding were identified: (1) High-Stable: ∼100% of feeds from bottles across infancy; (2) Rapid-Increase: <30% of feeds from bottles during the neonatal assessment, increasing to ∼100% by 6 months; (3) Gradual-Increase: <10% of feeds from bottles during the neonatal assessment, gradually increasing to ∼100% by 12 months; and (4) Low-Stable: <5% of feeds from bottles across the majority of infancy. Bottle-feeding groups had significantly different WAZ trajectories across infancy; by 12 months, the High-Stable and Rapid-Increase groups had significantly higher WAZs compared with the Gradual-Increase and Low-Stable groups (p < .001). The association between bottle-feeding group membership and WAZ trajectories was not confounded by sociodemographic characteristics or the extent to which infants received breast milk.

CONCLUSION

High-intensity bottle use during early infancy may place infants at higher risk for excess weight gain. Supports and policies that help mothers delay high-intensity bottle use until later infancy are warranted.

Associations between bottle-feeding intensity and maternal encouragement of bottle-emptying

Objective

To explore longitudinal associations between bottle-feeding and maternal encouragement of infant bottle-emptying during the first 6 months of infancy.

Design

Mothers completed questionnaires during the third trimester of pregnancy, then monthly during the first 6 months postpartum. Questionnaires assessed family demographics, maternal and infant weight status, infant feeding patterns and maternal encouragement of infant bottle-emptying.

Setting

The Infant Feeding Practices Study 2, conducted by the US Centers for Disease Control and Prevention and the Food and Drug Administration.

Subjects

Mothers (n 1776).

Results

Repeated-measures regression was used to explore associations between bottle-feeding intensity (BFI; defined as the percentage of daily feedings that were from a bottle) and encouragement of bottle-emptying. Mothers who reported consistently high or consistently low BFI also exhibited consistently higher or lower frequency of encouraging their infants to empty the bottle (respectively) across the first 6 months of infancy, whereas mothers who reported increases in their BFI also exhibited concomitant increases in the frequency to which they encouraged their infants to finish the bottle. More frequent encouragement of bottle-emptying was also associated with feeding expressed breast milk (P<0·001), and lower parity (P=0·01), pre-pregnancy BMI (P=0·002) and infant birth weight (P=0·001).

Conclusions

More frequent use of bottles for infant feeding was significantly associated with more frequent encouragement of bottle-emptying. Further research using causal designs is needed to better understand whether the use of bottles promotes this controlling feeding practice or whether mothers with more controlling feeding practices opt to bottle-feed.

An Experimental Approach to Study Individual Differences in Infants' Intake and Satiation Behaviors during Bottle-Feeding

BACKGROUND

As a group, bottle-fed infants are at higher risk for rapid weight gain compared with breast-fed infants. However, little is known about individual differences in feeding behaviors of bottle-feeding infants, as well as maternal and infant characteristics associated with bottle-feeding outcomes.

METHODS

We conducted a 2-day, within-subject study of 21 formula-feeding dyads; the within-subject factor was feeding condition: mother-led (ML; mothers were given the instruction to feed their infants as they typically would) vs. infant-led (IL; the experimenter ensured feeding began when infants signaled hunger and ended when they rejected the bottle on three consecutive occasions). Intake was determined by bottle weight; feedings were video-recorded and later analyzed to determine feeding duration and types of satiation behaviors displayed. Percent difference scores were calculated for each outcome as [((ML - IL)/IL) × 100] to standardize differences among dyads. Mothers completed questionnaires of feeding styles and infant temperament.

RESULTS

On average, infants consumed ∼42% more formula during the ML- than IL-condition (p = 0.03). However, notable variation existed in difference scores for intake (range = -52.8% to 268.9%; higher scores reflect greater intake during ML than IL). Stepwise regression illustrated that greater intakes during the ML-condition were predicted by the combination of: (1) higher infant age; (2) lower levels of infant rhythmicity and adaptability; (3) higher levels of infant positive mood; and (4) lower levels of maternal restrictive and responsive feeding styles.

CONCLUSIONS

This objective, experimental approach illustrated that variation in bottle-feeding outcomes is associated with characteristics of both members of the dyad.

Early Breast Milk Pumping Intentions Among Postpartum Women

INTRODUCTION

Milk expression has become common, but little is known about women's intentions and motivations for pumping. Our objectives were to measure, among newly postpartum women, intentions related to breast milk feeding and pumping, reasons for intending to pump, and timing of pumping initiation.

METHODS

We conducted a cross-sectional study at a large university hospital in 2015 using a convenience sample of 100 women before their discharge following delivery, who intended to feed their infant breast milk for at least 6 months.

RESULTS

All participants planned to feed their baby at the breast. Ninety-eight percent said that they would use a breast pump to express milk for their baby, with most of this subset (69%) intending to start within weeks of delivery. Over a quarter of participants (29%) had already initiated pumping or intended to initiate within the subsequent few days. Primiparae were more likely to report having already started pumping at the time of the interview. For all women, the most common reason for pumping was to keep up their milk supply. Women who started pumping while in the hospital also noted that they pumped to increase their milk supply and overcome latch difficulties.

CONCLUSIONS

The common intention to use a breast pump so early after delivery indicates a need for increased lactation support to reduce concerns about having an insufficient milk supply immediately following delivery. Additionally, clinicians who help facilitate breastfeeding should be aware of how early women intend to use a breast pump.

Effect of Human Milk Appetite Hormones, Macronutrients, and Infant Characteristics on Gastric Emptying and Breastfeeding Patterns of Term Fully Breastfed Infants

Human milk (HM) components influence infant feeding patterns and nutrient intake, yet it is unclear how they influence gastric emptying (GE), a key component of appetite regulation. This study analyzed GE of a single breastfeed, HM appetite hormones/macronutrients and demographics/anthropometrics/body composition of term fully breastfed infants (n = 41, 2 and/or 5 mo). Stomach volumes (SV) were calculated from pre-/post-feed ultrasound scans, then repeatedly until the next feed. Feed volume (FV) was measured by the test-weigh method. HM samples were analyzed for adiponectin, leptin, fat, lactose, total carbohydrate, lysozyme, and total/whey/casein protein. Linear regression/mixed effect models were used to determine associations between GE/feed variables and HM components/infant anthropometrics/adiposity. Higher FVs were associated with faster (−0.07 [−0.10, −0.03], p < 0.001) GE rate, higher post-feed SVs (0.82 [0.53, 1.12], p < 0.001), and longer GE times (0.24 [0.03, 0.46], p = 0.033). Higher whey protein concentration was associated with higher post-feed SVs (4.99 [0.84, 9.13], p = 0.023). Longer GE time was associated with higher adiponectin concentration (2.29 [0.92, 3.66], p = 0.002) and dose (0.02 [0.01, 0.03], p = 0.005), and lower casein:whey ratio (−65.89 [−107.13, −2.66], p = 0.003). FV and HM composition influence GE and breastfeeding patterns in term breastfed infants.

Factors Associated With Exclusive Breastfeeding Through Four Weeks Postpartum in Thai Adolescent Mothers

Breastfeeding initiation and duration are decreased in adolescent mothers compared to older mothers. A prospective descriptive cohort design was used to explore personal, social, cultural, and infant factors that explain and predict breastfeeding initiation and maintenance at 4 weeks postpartum. Adolescent mothers (N = 120) were recruited at prenatal clinics in Thailand. Data were collected at enrollment, during birth hospitalization (N = 102), and at 4 weeks postpartum (N = 96). Findings revealed breastfeeding attitudes, social support, and cultural beliefs about "being a good mother" were positively correlated with breastfeeding initiation. Furthermore, breastfeeding attitudes and social support were significant positive predictors of exclusive breastfeeding (both p ≥ .01) continuation through 4 weeks, whereas infant temperament was a significant negative predictor (p ≥ .04). Maternal competence at 4 weeks postpartum was also positively correlated with exclusive breastfeeding continuation.

The Effects of Leptin on Breastfeeding Behaviour

Breastfed infants have a reduced risk of becoming overweight and/or obese later in life. This protective effect has been partly attributed to leptin present in breastmilk. This study investigated 24-h variations of skim milk leptin and its relationship with breastmilk macronutrients and infant breastfeeding patterns. Exclusive breastfeeding mothers of term singletons (n = 19; age 10 ± 5 weeks) collected pre- and post-feed breastmilk samples for every breastfeed over a 24-h period and test-weighed their infants to determine milk intake at every breastfeed over a 24-h period. Samples (n = 454) were analysed for leptin, protein, lactose and fat content. Skim milk leptin concentration did not change with feeding (p = 0.184). However, larger feed volumes (>105 g) were associated with a decrease in post-feed leptin levels (p = 0.009). There was no relationship between the change in leptin levels and change in protein (p = 0.313) or lactose levels (p = 0.587) between pre- and post-feed milk, but there was a trend for a positive association with changes in milk fat content (p = 0.056). Leptin concentration significantly increased at night (p < 0.001) indicating a possible 24-h pattern. Leptin dose (ng) was not associated with the time between feeds (p = 0.232). Further research should include analysis of whole breastmilk and other breastmilk fractions to extend these findings.

Bottle-feeding practices during early infancy and eating behaviors at 6 years of age

BACKGROUND

Evidence suggests an association of breastfeeding with a maternal feeding style (MFS) that is less controlling than formula feeding, which, in turn, may improve a child's self-regulation of eating. This study examines associations of bottle-feeding practices during infancy with MFS and children's eating behavior (CEB) at 6 years old.

METHODS

We linked data from the Infant Feeding Practices Study II to the Year 6 Follow-Up, which include 8 MFS and CEB measures adapted from previous validated instruments. Bottle-feeding practices during the first 6 months estimated by using the Infant Feeding Practices Study II were bottle-feeding intensity (BFI), mother's encouragement of infant to finish milk in the bottle, and infant finishing all milk in the bottle. Adjusted odds ratios (aORs) for associations of bottle-feeding practices with MFS and CEB at 6 years old were calculated by using multivariable logistic regressions controlling for sociodemographic characteristics and other feeding practices (N = 1117).

RESULTS

Frequent bottle emptying encouraged by mothers during infancy increased odds of mothers encouraging their child to eat all the food on their plate (aOR: 2.37; 95% confidence interval [CI]: 1.65-3.41] and making sure their child eats enough (aOR: 1.62; 95% CI: 1.14-2.31) and of children eating all the food on their plate at 6 years old (aOR: 2.01; 95% CI: 1.05-3.83). High BFI during early infancy also increased the odds of mothers being especially careful to ensure their 6-year-old eats enough.

CONCLUSIONS

Bottle-feeding practices during infancy may have long-term effects on MFS and CEB. Frequent bottle emptying encouraged by mothers and/or high BFI during early infancy increased the likelihood of mothers pressuring their 6-year-old child to eat and children's low satiety responsiveness.

Infant body composition in the PEA POD® era: what have we learned and where do we go from here?

The availability of clinically feasible infant body composition assessment can inform current questions regarding the developmental origins of chronic disease. A strategic approach will facilitate more rapid advancement in knowledge. The objective of this study was to summarize published evidence and ongoing research activity in infant body composition using the PEA POD® infant body composition system. All published studies using the PEA POD® were identified and grouped according to study population and question. All centers with PEA POD® units were invited to participate in an online survey regarding past, current and future PEA POD® use, and results were analyzed using descriptive statistics. The resulting information was used to identify gaps or limitations in existing knowledge, thus highlighting potential research priorities. Twenty-seven published articles were identified and grouped into six research themes. Although the number of infants studied is significant in some areas, interpretation of data is limited by methodological differences. Survey responses were received from 16 of ∼60 centers. Research themes echoed those identified from the published literature. Controlling for or reporting potential confounding variables is essential for understanding infant body composition data. Measurement of health outcome variables would be helpful in identifying associations.

Body composition changes in the first 6 months of life according to method of feeding

BACKGROUND

Early feeding choices may affect long-term health outcomes. Therefore, understanding body composition changes in healthy breastfed infants has become an important research focus.

OBJECTIVES

The aims of this review were to investigate the body composition changes that occur during weight loss in breastfed term newborns and to examine body composition differences between exclusively/predominantly breastfed and exclusively formula-fed infants in the first 6 months of life.

METHODS

We performed a review of the existing literature using PubMed. We searched for studies published in English since January 1, 2000, that involved human infants ranging in age from birth to 6 months. We used the following MEDLINE Medical Subject Headings: ((breastfeeding) OR (infant formula)) AND ((body composition) OR (bioelectrical impedance) OR (absorptiometry, photon) OR (total body potassium) OR (isotope dilution) OR (air-displacement plethysmography)). Our search yielded 6 studies.

RESULTS

Two studies reported that newborn weight loss was due to a reduction in the quantity of both fat mass and fat-free mass. Three out of 4 articles that evaluated body composition changes according to method of feeding reported no differences in body composition between exclusively/predominantly breastfed and exclusively formula-fed infants in the first 4.5 months of life. One study reported that exclusively breastfed infants at 3 months of age and exclusively breastfed boys at 6 months of age had higher fat mass contents compared to exclusively formula-fed infants.

CONCLUSION

Because of the limited number of studies available, larger studies are needed to clarify the differences in body composition between exclusively/predominantly breastfed and exclusively formula-fed infants.

Executive summary: Evaluating the evidence base to support the inclusion of infants and children from birth to 24 mo of age in the Dietary Guidelines for Americans--"the B-24 Project"

The Dietary Guidelines for Americans (DGA) are the cornerstone of US government efforts to promote health and prevent disease through diet and nutrition. The DGA currently provides guidelines for ages ≥ 2 y. In an effort to determine the strength of the evidence to support the inclusion of infants and children from birth to age 24 mo, the partner agencies led by the Department of Health and Human Services Office of Disease Prevention and Health Promotion and the USDA Center for Nutrition Program and Policy initiated the project entitled "Evaluating the evidence base to support the inclusion of infants and children from birth to 24 months of age in the Dietary Guidelines for Americans--the B-24 Project." This project represents the first step in the process of applying systematic reviews to the process of deciding whether the evidence is sufficient to include this age group in future editions of the DGA. This supplement includes the B-24 Executive Summary, which describes the B-24 Project and the deliberations of the 4 working groups during the process of developing priority topics for the systematic review, and a research agenda to address the critical gaps. Also included in this supplement issue is an article on the Nutrition Evidence Library methodology for developing systematic review questions and articles from the invited content presenters at the B-24 Prime meeting.

Presence and dynamics of leptin, GLP-1, and PYY in human breast milk at early postpartum

OBJECTIVE

The presence of appetite hormones, namely glucagon-like peptide-1 (GLP-1), peptide YY (PYY), and leptin in breast milk may be important in infant feeding regulation and infant growth. This study evaluated whether concentrations of GLP-1, PYY, and leptin change across a single feeding (from fore- to hindmilk), and are associated with maternal and infant anthropometrics.

DESIGN AND METHODS

Thirteen postpartum women (mean ± SD: 25.6 ± 4.5 years, 72.0 ± 11.9 kg) provided fore- and hindmilk samples 4-5 weeks after delivery and underwent measurements of body weight and composition by Dual X-ray Absorptiometry. GLP-1, PYY, and leptin concentrations were measured using radioimmunoassay, and milk fat content was determined by creamatocrit.

RESULTS

Concentration of GLP-1 and content of milk fat was higher in hindmilk than foremilk (P ≤ 0.05). PYY and leptin concentrations did not change between fore- and hindmilk. Both leptin concentration and milk fat content were correlated with indices of maternal adiposity, including body mass index (r = 0.65-0.85, P < 0.02), and fat mass (r = 0.65-0.84, P < 0.02). Hindmilk GLP-1 was correlated with infant weight gain from birth to 6 months (r = -0.67, P = 0.034).

CONCLUSION

The presence of appetite hormones in breast milk may be important in infant appetite and growth regulation.

Diet, sensitive periods in flavour learning, and growth

Diet in early infancy has an impact on early growth and the formation of flavour preferences, as well as on later life health outcomes. Although breast milk is the preferred source of nutrition during infancy, more than half of American infants receive infant formula by the age of 4 months. As a group, formula-fed infants weigh more by the age of one year and have a greater risk for later obesity than breastfed infants. However, a recent randomized study found that, when compared to breastfed infants, infants fed an extensively hydrolysed protein formula (ePHF) had more normative weight gain velocity than infants fed cow's milk formula (CMF). Therefore, grouping all formula-fed infants together with respect to certain health outcomes such as obesity may not be appropriate. Scientific evidence also suggests that there are sensitive periods for flavour learning. Infants become familiar with and learn to accept the flavours they experience through their mother's amniotic fluid and breast milk as well as formula. These early experiences influence flavour preferences of children that may affect food choices and therefore later life health. Further research on the influence of early diet on growth, flavour preferences, and food choices is imperative.

The quiet revolution: breastfeeding transformed with the use of breast pumps

A quiet revolution has been taking place in the feeding of US infants in the form of women using electric breast pumps. This revolution in milk expression may be a boon for both mothers and infants if more infants are fed human milk or if they receive human milk for a longer period. Milk expression may also be problematic for mothers, and it may be particularly problematic for infants if they are fed too much, fed milk of an inappropriate composition, or fed milk that is contaminated. As a result, the time has come to determine the prevalence of exclusive and periodic breast milk expression and the consequences of these behaviors for the health of mothers and their infants.