Human milk fatty acid composition and its association with maternal blood and adipose tissue fatty acid content in a cohort of women from Europe.

PURPOSE: Human milk (HM) composition is influenced by factors, like maternal diet and body stores, among other factors. For evaluating the influence of maternal fatty acid (FA) status on milk FA composition, the correlation between FA content in HM and in maternal plasma, erythrocytes, and adipose tissue was investigated. METHODS: 223 European women who delivered at term, provided HM samples over first four months of lactation. Venous blood and adipose tissue (only from mothers who consented and underwent a C-section delivery) were sampled at delivery. FAs were assessed in plasma, erythrocytes, adipose tissue, and HM. Evolution of HM FAs over lactation and correlations between FA content in milk and tissues and between mother's blood and cord blood were established. RESULTS: During lactation, arachidonic acid (ARA) and docosahexaenoic acid (DHA) significantly decreased, while linoleic acid (LA), alpha-linolenic acid (ALA), and eicosapentaenoic acid (EPA) remained stable. Positive correlations were observed between HM and adipose tissue for palmitic, stearic, oleic, and polyunsaturated fatty acids (PUFAs). Correlations were found between milk and plasma for oleic, LA, ARA, ALA, DHA, monounsaturated fatty acids (MUFAs), and PUFAs. No correlation was observed between erythrocytes and HM FAs. LA and ALA were more concentrated in maternal blood than in infant blood, contrary to ARA and DHA, supporting that biomagnification of LCPUFAs may have occurred during pregnancy. CONCLUSIONS: These data show that maternal adipose tissue rather than erythrocytes may serve as reservoir of PUFAs and LCPUFAs for human milk. Plasma also supplies PUFAs and LCPUFAs to maternal milk. If both, adipose tissue and plasma PUFAs, are reflection of dietary intake, it is necessary to provide PUFAs and LCPUFAs during pregnancy or even before conception and lactation to ensure availability for mothers and enough supply for the infant via HM.

Human milk oligosaccharides, infant growth, and adiposity over the first 4 months of lactation.

BACKGROUND: The relationship between human milk oligosaccharides (HMOs) and infant growth and adiposity is not fully understood and comprehensive studies are missing from the current literature. METHODS: We screened and recruited 370 healthy, pregnant women and their infants from seven European countries. Breastmilk samples were collected using standardized procedures at six time points over 4 months, as were infant parameters. Correlations and associations between HMO area under the curve, anthropometric data, and fat mass at 4 months were tested. RESULTS: Lacto-N-neotetraose had a negative correlation with the change in length (rs = -0.18, P = 0.02). Sialyllacto-N-tetraose c (LSTc) had a positive correlation with weight for length (rs = 0.19, P = 0.015). Infants at the 25th upper percentile were fed milk higher in 3'-sialyllactose and LSTc (P = 0.017 and P = 0.006, respectively) compared to the lower 25th percentile of the weight-for-length z-score gain over 4 months of lactation. No significant associations between growth and body composition and Lewis or secretor-dependent HMOs like 2'-fucosyllactose were identified. CONCLUSIONS: Changes in the HMO composition of breastmilk during the first 4 months appear to have little influence on infant growth and body composition in this cohort of healthy mothers and infants. IMPACT: Modest associations exist between individual HMO and infant growth outcomes at least in healthy growing populations. Our study provides a comprehensive investigation of associations between all major HMO and infant growth and adiposity including several time points. Certain groups of HMOs, like the sialylated, may be associated with adiposity during the first months of lactation. HMO may modulate the risk of future metabolic disease. Future population studies need to address the role of specific groups of HMOs in the context of health and disease to understand the long-term impact.

Impact of maternal characteristics on human milk oligosaccharide composition over the first 4 months of lactation in a cohort of healthy European mothers.

Human milk oligosaccharide (HMO) composition varies among lactating mothers and changes during the course of lactation period. Interindividual variation is largely driven by fucosyltransferase (FUT2 and FUT3) polymorphisms resulting in 4 distinct milk groups. Little is known regarding whether maternal physiological status contributes to HMO variability. We characterized the trajectories of 20 major HMOs and explored whether maternal pre-pregnancy body mass index (ppBMI), mode of delivery, or parity may affect milk HMO composition. Using longitudinal breastmilk samples from healthy mothers (n = 290) across 7 European countries, we characterized HMO composion and employed mixed linear models to explore associations of maternal characteristics with individual HMOs. We observed HMO-specific temporal trajectories and milk group dependencies. We observed relatively small but significant differences in HMO concentrations based on maternal ppBMI, mode of delivery and parity. Our findings suggest that HMO composition to be regulated time-dependently by an enzyme as well as substrate availability and that ppBMI, mode of delivery, and parity may influence maternal physiology to affect glycosylation marginally within the initital period of lactation. Our observational study is the largest European standardized and longitudinal (up to 4 months) milk collection study assessing HMO concentrations and basic maternal characteristics. Time of lactation and milk groups had the biggest impact on HMO variation. Future studies need to elucidate these observations and assess the physiological significance for the breastfed infant.

Subclinical Mastitis in a European Multicenter Cohort: Prevalence, Impact on Human Milk (HM) Composition, and Association with Infant HM Intake and Growth.

Background: Subclinical mastitis (SCM) is an inflammatory condition of the mammary gland. We examined the effects of SCM on human milk (HM) composition, infant growth, and HM intake in a mother-infant cohort from seven European countries. Methods: HM samples were obtained from 305 mothers at 2, 17, 30, 60, 90, and 120 days postpartum. SCM status was assessed using HM Sodium (Na): Potassium (K) ratio >0.6. Levels of different macro- and micronutrients were analyzed in HM. Results: SCM prevalence in the first month of lactation was 35.4%. Mean gestational age at delivery was lower and birth by C-section higher in SCM mothers (p ≤ 0.001). HM concentrations of lactose, DHA, linolenic acid, calcium, and phosphorous (p < 0.05 for all) was lower, while total protein, alpha-lactalbumin, lactoferrin, albumin, arachidonic acid to DHA ratio, n-6 to n-3 ratio and minerals (iron, selenium, manganese, zinc, and copper) were higher (p < 0.001 for all) in mothers with SCM. There were no differences in infant growth and HM intake between non-SCM and SCM groups. Conclusion: We document, for the first time, in a large European standardized and longitudinal study, a high prevalence of SCM in early lactation and demonstrate that SCM is associated with significant changes in the macro- and micronutrient composition of HM. Future studies exploring the relation of SCM with breastfeeding behaviors and developmental outcomes are warranted.