Environmental determinants of human milk composition in relation to health outcomes.

Humans are exposed to environmental factors at every stage of life including infancy. The aim of this mini-review was to present a narrative of environmental factors influencing human milk composition. Current literature shows lactation is a dynamic process and is responsive to multiple environmental challenges including geographical location, lifestyle, persistent pollutants and maternal factors (ethnicity, diet, stress, allergy and adiposity) that may influence human milk composition in a synergistic manner and should be considered in order to improve infant and maternal outcomes on a populations scale. Further interventional studies on larger international cohorts are needed to elucidate these complex relationships. Lactating women should aim for a healthy lifestyle and maintain a healthy body composition prior to and throughout the reproductive period, including during lactation.

Distinct maternal amino acids and oxylipins predict infant fat mass and fat-free mass indices.

Interested in maternal determinants of infant fat mass index (FMI) and fat-free mass index (FFMI), considered as predictors for later development of obesity, we analysed amino acids (AA) and oxylipins in maternal serum and breast milk (BM). FMI and FFMI were calculated in 47 term infants aged 4 months (T4). Serum AA were analysed in pregnancy (T1, T2) and 6-8 weeks postpartum (T3). At T3, AA and oxylipins were analysed in BM. Biomarker-index-associations were identified by regression analysis. Infant FMI (4.1 ± 1.31 kg/m2; MW ± SD) was predicted by T2 proline (R2 adj.: 7.6%, p = .036) and T3 BM 11-hydroxy-eicosatetraenoic-acid (11-HETE) and 13-hydroxy-docosahexaenoic-acid (13-HDHA; together:35.5% R2 adj., p < .001). Maternal peripartum antibiotics (AB) emerged as confounders (+AB: 23.5% higher FMI; p = .025). Infant FFMI (12.1 ± 1.19 kg/m2; MW ± SD) was predicted by histidine (R2 adj.: 14.5%, p < .001) and 17-HDHA (BM, R2 adj.:19.3%, p < .001), determined at T3. Confirmed in a larger cohort, the parameters could elucidate connections between maternal metabolic status, nutrition, and infant body development.

Infant Body Composition in an Asian Pacific Islander Population.

BACKGROUND: Normative infant body composition data using air displacement plethysmography (ADP) are from primarily Caucasian populations. Racial differences may exist. OBJECTIVES: To describe body composition in Asian and Pacific Islander infants and compare them to previously published data on Caucasian infants. DESIGN: Body composition was measured using ADP with the PEA POD® Infant Body Composition System in 249 healthy full-term newborns in a predominately Asian and Pacific Islander population in Hawaii within the first 3 days of life and compared to published data on Caucasian infants with multiple t-tests adjusted for false discovery rate. RESULTS: There were no differences in percent body fat between Asian, Pacific Islander, or mixed race Asian Pacific Islander infants. Both Asian and Pacific Islander infants had significantly higher percent body fat than Caucasians from Italy in Europe (13.2% and 11.8% vs 8.9%, p < 0.01 among males, 15.3% and 15.6% vs 8.7%, p < 0.01 among females) but not when compared to Caucasians from New York. CONCLUSIONS: Racial and geographical differences in body composition exist at birth between Asian and Pacific Islanders and other Caucasian cohorts. Previously published ADP nomograms must be interpreted with caution. Future studies are needed to investigate the impact of environmental, perinatal, and genetic factors on infant body composition and its relationship to future cardiometabolic morbidity. Efforts to address racial disparities in cardiometabolic disease measures must also address pre-conceptual maternal health, which may have long-term implications on future body composition in offspring.

Relationships between the Intakes of Human Milk Components and Body Composition of Breastfed Infants: A Systematic Review.

Human milk provides all of the elements necessary for infant growth and development. Previous studies have reported associations between breastfeeding and a reduced risk of developing obesity and late-onset metabolic disorders; however, the underlying mechanisms are poorly understood. Recently, intakes of human milk components have been associated with infant body composition, which is likely partially implicated in the reduced risk of developing childhood obesity among breastfed infants. In this systematic review, we searched electronic bibliographic databases for studies that explored relationships between the 24 h intakes of human milk macronutrients and bioactive components and infant body composition and/or growth parameters. Of 13 eligible studies, 10 assessed relationships of infant body composition and growth outcomes with human milk macronutrients, while 8 studies assessed relationships with human milk bioactive components. Significant time-dependent relationships with infant anthropometrics and body composition were found for intakes and no relationships for concentrations of several human milk components, such as lactose, total protein, and human milk oligosaccharides, suggesting that measuring concentrations of human milk components without quantifying the intake by the infant may provide a limited understanding. Future studies investigating the effect of human milk components on infant growth and body composition outcomes should consider measuring the actual intake of components and employ standardised methods for measuring milk intake.

Gestational Diabetes Mellitus Is Associated with Altered Abundance of Exosomal MicroRNAs in Human Milk.

PURPOSE: Human milk (HM) is a unique biological fluid that is enriched with a variety of factors, including microRNAs (miRNAs) that potentially provide both short- and long-term benefits to the infants. miRNAs are packaged within exosomes, making them bioavailable to infants. Gestational diabetes mellitus (GDM) may affect the abundance of exosomal miRNAs in HM, providing a mechanism for growth and adiposity variation in infants of mothers with GDM in early life. Therefore, the purposes of this study were to examine the impact of GDM on select miRNAs (miRNA-148a, miRNA-30b, miRNA-let-7a, and miRNA-let-7d) involved in metabolism and to examine the association of these miRNAs with measures of infant body composition in the first 6 months of life. METHODS: Milk samples were collected from a cohort of 94 mothers (62 mothers without GDM and 32 mothers with GDM) matched on body mass index strata at 1 month post partum. miRNA abundance was measured by real-time polymerase chain reaction. Linear regression models were used to examine potential differences in miRNA abundance in women with and without GDM, testing associations between miRNA abundance and infant growth and body composition measures from 1 to 6 months. FINDINGS: The abundances of miRNA-148a, miRNA-30b, miRNA-let-7a, and miRNA-let-7d were reduced in milk from mothers with GDM. Independent of GDM status, higher maternal diet quality was associated with increased abundance of each of the measured miRNAs. miRNA-148a was negatively associated with infant weight, percentage of body fat, and fat mass, whereas miRNA-30b was positively associated with infant weight and fat mass at 1 month of age. There was no association of milk miRNA-148a and miRNA-30b with infant weight at 1 month of age or with body composition measures at 3 months of age; however, miRNA-148a was negatively associated with infant weight at 6 months of age. IMPLICATIONS: If supported by randomized dietary supplementation or other intervention trials, HM miRNAs may be a therapeutic target to mitigate risk of metabolic outcomes in offspring of women with GDM.

No sustained effects of an intervention to prevent excessive GWG on offspring fat and lean mass at 54 weeks: Yet a greater head circumference persists.

BACKGROUND: LIFT (Lifestyle Intervention for Two) trial found that intervening in women with overweight and obesity through promoting healthy diet and physical activity to control gestational weight gain (GWG) resulted in neonates with greater weight, lean mass and head circumference and similar fat mass at birth. Whether these neonate outcomes are sustained at 1-year was the focus of this investigation. METHODS: Measures included body composition by PEA POD air displacement plethysmography (ADP) and Echo Infant quantitative magnetic resonance (QMR) and head circumference at birth (n = 169), 14 (n = 136) and 54 weeks (n = 137). Differences in fat and lean mass between lifestyle intervention (LI) and Usual care (UC) groups were examined using ANCOVA adjusting for maternal age and BMI, GWG, offspring sex and age. RESULTS: Compared to UC, LI infants had similar weight (112 ± 131 g; P = .40), fat mass (14 ± 80 g; P = .86), lean mass (100 ± 63 g; P = .12) at 14 weeks and similar weight (168 ± 183 g; P = .36), fat mass (148 ± 124 g; P = .24), lean mass (117 ± 92 g; P = .21) at 54 weeks. Head circumference was greater in LI at 54 weeks (0.46 ± 2.1 cm P = .03). CONCLUSIONS: Greater lean mass observed at birth in LI offspring was not sustained at 14 and 54 weeks, whereas the greater head circumference in LI offspring persisted at 54 weeks.

Association of parental body mass index before pregnancy on infant growth and body composition: Evidence from a pregnancy cohort study in Malaysia.

BACKGROUND AND OBJECTIVES: Parental body mass index (BMI) is strongly linked with the development of offspring overweight and obesity. However, there are a limited number of studies focusing on the association of parental body mass index before pregnancy on offspring growth and body composition in early life, particularly in developing countries. METHODS: Data from the University Sains Malaysia (USM) Pregnancy Cohort which consists of 153 mother-offspring pairs were used. Data were collected using interview-administered questionnaires and anthropometric measurements were also obtained. Multiple linear regression and generalised equation estimation (GEE) were used to examine the direction and impact of the association between parental BMI and child growth and body composition (weight for age, height for age, body mass index for age, weight for height and fat mass at age 2m, 6m, and 12m). Potential confounders, including validated measures of maternal diets and physical activity during pregnancy, were considered. RESULTS: Of 153 parents, one-quarter of the mothers and 42.2% of the fathers, respectively, were overweight or obese before pregnancy. A significant association was found between maternal BMI and child's weight for height z-score (WHZ) and body mass index for age z-score (BAZ). CONCLUSIONS: Having high pre-pregnancy BMI may increase BMI and WAZ of offspring in early life. Findings from this study emphasise the importance of monitoring maternal weight status, particularly before and during pregnancy and early life of offspring among Malaysians.

Striking differences in estimates of infant adiposity by new and old DXA software, PEAPOD and skin-folds at 2 weeks and 1 year of life.

BACKGROUND: Infant adiposity better predicts childhood obesity/metabolic risk than weight, but technical challenges fuel controversy over the accuracy of adiposity estimates. OBJECTIVE: We prospectively measured adiposity (%fat) in term newborns (NB) at 2 weeks (n = 41) and 1 year (n = 30). METHODS: %fat was measured by dual X-ray absorptiometry (DXA), PEAPOD and skin-folds (SF). DXAs were analyzed using Hologic Apex software 3.2(DXAv1) and a new version 5.5.2(DXAv2). RESULTS: NB %fat by DXAv2 was 55% higher than DXAv1 (14.2% vs. 9.1%), 45% higher than SF (9.8%), and 36% higher than PEAPOD (10.4%). Among NB, Pearson correlations were 0.73-0.89, but agreement (intra-class correlations) poor between DXAv2 and DXAv1 (0.527), SF (0.354) and PEAPOD (0.618). At 1 year, %fat by DXAv2 was 51% higher than DXAv1 (33.6% vs. 22.4%), and twice as high compared with SF (14.6%). Agreement was poor between DXAv2 and DXAv1 (0.204), and SF (0.038). The absolute increase in %fat from 2 weeks to 1 year was 19.7% (DXAv2), 13.6% (DXAv1) and only 4.8% by SF. CONCLUSION: Analysis of the same DXA scans using new software yielded considerably higher adiposity estimates at birth and 1 year compared with the previous version. Using different modalities to assess body composition longitudinally is problematic. Standardization is gravely needed to determine how early life exposures affect childhood obesity/metabolic risk.

Associations between human milk oligosaccharides and infant body composition in the first 6 mo of life.

BACKGROUND: Evidence linking breastfeeding to reduced risk of developing childhood obesity is inconclusive, yet previous studies have not considered variation in specific components of breast milk that may affect early development. OBJECTIVE: We examined whether differences in the composition of human milk oligosaccharides (HMOs) correlate with infant growth and body composition at 1 and 6 mo of age. DESIGN: Twenty-five mother-infant dyads were recruited from the University Hospital at the University of Oklahoma Health Sciences Center. Infants were breastfed for 6 mo. Breast-milk and infant measures were obtained at 1 and 6 mo of infant age. HMO composition was analyzed by high-pressure liquid chromatography, and infant growth (length and weight) and body composition (percentage fat, total fat, lean mass) were measured by dual-energy X-ray absorptiometry. Relations between HMOs and infant growth and body composition were examined by using multiple linear regression. A priori covariates included maternal prepregnancy body mass index, pregnancy weight gain, and infant age and sex. RESULTS: Higher HMO diversity and evenness at 1 mo were associated with lower total and percentage fat mass at 1 mo. At 1 mo, each 1-µg/mL increase in lacto-N-fucopentaose (LNFP) I was associated with a 0.40-kg lower infant weight (P = 0.03). At 6 mo, each 1-µg/mL increase in LNFPI was associated with a 1.11-kg lower weight (P = 0.03) and a 0.85-g lower lean mass (P = 0.01). At 6 mo, each 1-µg/mL increase in LNFPI was associated with a 0.79-g lower fat mass (P = 0.02), whereas disialyl-lacto-N-tetraose and LNFPII were associated with a 1.92-g (P = 0.02) and 0.42-g (P = 0.02) greater fat mass, respectively. At 6 mo, each 1-µg/mL increase in fucosyl-disialyl-lacto-N-hexaose and lacto-N-neotetraose was associated with 0.04% higher (P = 0.03) and 0.03% lower (P < 0.01) body fat, respectively. CONCLUSION: These findings support the hypothesis that differences in HMO composition in mother's milk are associated with infant growth and body composition. This trial was registered at clinicaltrials.gov as NCT02535637.