Growth Factor Concentrations in Human Milk Are Associated With Infant Weight and BMI From Birth to 5 Years

Abstract

Background: Human milk bioactives may play a role in infant health and development. Although the variability in their concentrations in milk is well-established, the impact of differential milk profiles on infant growth outcomes remains unclear. Thus, the aim of the present study was to investigate whether different concentrations of metabolic hormones are associated with different weight and BMI in infants beyond the first year of life. Methods: Milk samples at 2.6 (±0.4) months after birth and anthropometric measures at 13 months, 2, 3, and 5 years were collected as part of the Finnish STEPS cohort study from 501 mothers and the respective 507 infants. Leptin, adiponectin, insulin-like growth factor (IGF)-1 and cyclic glycine-proline (cGP) in milk were analyzed. Multiple regression models and a repeated measures mixed model were used to examine associations between milk hormone concentrations and weight and BMI z-scores across time, at each time-point, and weight gain from birth to each follow-up visit. All models were corrected for birth weight, infant sex, duration of exclusive and total breastfeeding, time of introduction of solid foods and maternal pre-pregnancy BMI. Results: Higher milk IGF-1 was associated with higher weight at 13 months (p = 0.004) but lower weight at 3 (p = 0.011) and 5 years of age (p = 0.049). Higher cGP was associated with lower weight across the 5 years (p = 0.019) but with higher BMI at 5 years (p = 0.021). Leptin and adiponectin did not display associations with infant growth at this time. Sex interactions were also absent. Conclusions: Our results suggest that the interplay between human milk-borne IGF-1 and cGP is similar to that reported in other mammals and may have an important role Galante et al. Breastmilk IGF-1 and Infant Growth in defining infant growth trajectories beyond the first year of life. Further research should explore the determinants and origins of these milk-borne compounds and evaluate their effect on infant growth and metabolism.

Metabolic Hormone Profiles in Breast Milk From Mothers of Moderate-Late Preterm Infants Are Associated With Growth From Birth to 4 Months in a Sex-Specific Manner

“…The results confirmed our hypothesis that variability in MOM hormonal composition may contribute to variation in postnatal growth and that infants of different sex are likely to respond differently to the same concentrations of MOM components. Importantly, the data also confirm our previous observations in the healthy Finnish STEPS cohort regarding the correlations between MOM IGF-1 concentrations and infant weight (18), highlighting the possibility that exposure to varied MOM IGF-1 concentrations is associated with variation in infant growth outcomes (e.g., weight, BMI, body composition). We observed fat-free mass at discharge from hospital and at 4 months' corrected age was lower for infants whose mothers had a higher MOM protein content during early lactation (day 5 postpartum).…”

“…Such metabolic hormones contained in HM (i.e., leptin, adiponectin, and growth factors) regulate multiple biological functions (14) and are potential mediators of infant health outcomes across the life course by providing important environmental cues at critical time-points of developmental plasticity (15)(16)(17). In this context, our study in a healthy Finnish cohort has recently demonstrated that growth trajectories up to 5 years were associated with HM concentrations of insulin-like growth factor (IGF)-1 (18). Similarly, others have reported associations between HM composition and diverse infant growth trajectories (19)(20)(21)(22).…”

Breast Milk: A Source of Functional Compounds with Potential Application in Nutrition and Therapy

“…IGF1 is found in human milk, in a bioactive form in the intestine of breastfed infants and in their blood serum at higher concentrations [ 195 ]. Very recent research links its concentration in human milk with an important role in defining infant growth trajectories beyond the first year of life [ 230 ] and supports previous studies that highlighted its importance in infant growth and regulation of fat accumulation during childhood [ 231 ].…”

Centering human milk composition as normal human biological variation

“…Such predicted associations between maternal BMI and milk metabolic hormones, based on the strong and consistent association between body composition and leptin, are frequently reported even in the absence of such data (Andreas et al, 2016;Chan et al, 2018;Galante et al, 2020;Martin et al, 2006;Quinn et al, 2015;Sims et al, 2020;Young et al, 2017). Such interpretations act to obscure important, small biological differences in milk composition that may have important long term programming effects on infant metabolic phenotype (Fewtrell et al, 2020;Kuzawa & Quinn, 2009).…”