Relationship of insulin, glucose, leptin, IL‐6 and TNF‐α in human breast milk with infant growth and body composition

Abstract

Numerous appetite, growth, obesity-related hormones and inflammatory factors are found in human breast-milk, but there is little evidence on their relationship with infant body composition. The purpose of the present cross-sectional pilot study was to assess the cross-sectional associations of appetite-regulating hormones and growth factors (leptin, insulin, glucose) and inflammatory factors (IL-6 and TNF-α) in human breast-milk with infant size, adiposity, and lean tissue at 1-month of age in healthy term infants. Human breast-milk was collected from nineteen exclusively breast-feeding mothers using one full breast expression between 8:00 and 10:00 am. The milk was then mixed, aliquoted, stored at −80°C and then centrifuged to remove the milk fat, prior to analyses using commercially available immunoassay kits; milk analytes were natural log transformed prior to analysis. Infant body composition was assessed using a Lunar iDXA v11-30.062 scanner (Infant whole body analysis enCore 2007 software, GE, Fairfield, CT). Maternal pre-pregnancy BMI was positively associated with milk leptin concentration (p=0.0027), and so maternal-BMI-adjusted Spearman correlations were examined between breast-milk analytes and infant growth and body composition variables. As previously reported, greater milk leptin was associated with lower BMIZ (r= −0.54, p=0.03). Glucose was positively associated with relateive weight (r = 0.6, p=0.01), and both fat and lean mass (0.43 – 0.44, p<0.10). Higher concentrations of milk insulin were associated with lower infant weight, relative weight, and lean mass (r = −0.49 – 0.58, p<0.06). Higher milk IL-6 was associated with lower relative weight, weight gain, percent fat, and fat mass (r = −0.55 – 0.70, p<0.03 for all), while higher TNF-α was associated with lower lean mass (r=−0.58, p=0.05), but not measures of adiposity. These preliminary data suggest for the first time that in the first months of life, breast-milk concentrations of insulin, glucose, IL-6 and TNF-α, in addition to leptin, may be bioactive and differentially influence the accrual of fat and lean body mass.

Maternal insulin resistance and transient hyperglycemia impact the metabolic and endocrine phenotypes of offspring

“…Breast milk composition has been shown to influence infant growth and accrual of fat and lean body mass (12). Therefore, postnatal consumption of breast milk produced by LIRKO mothers might be a contributor to the metabolic phenotype observed in CL offspring.…”

Development of Early Adiposity in Infants of Mothers With Gestational Diabetes Mellitus

“…Breast milk alterations, including higher glucose concentration, have been demonstrated in mothers with type 1 diabetes, which may influence infant body composition (36,37). The exploration of breast milk composition in mothers with GDM has been limited, and an examination of the relationship among GDM status, breast milk composition, and infant adiposity may provide further insight.…”

Growth and Life Course Health Development

“…Breast milk contains growth signaling compounds, ranging from leptin to inflammatory cytokines such as TNF-α and IL-6, with effects on skeletal, fat, and lean mass accrual. Increasing breast milk leptin levels have been associated with lower infant weight gain through the sixth postnatal month (Schuster et al 2011) and increasing IL-6 levels with lower infant weight-for-length Z-score and fat mass at 1 month of age (Fields and Demerath 2012), effects that attenuate at later ages (Brunner et al 2015). The leptin and IL-6 effects on weight gain and fat mass accrual may reflect influences on appetite and/or digestive processes via gastrointestinal epithelial cell receptors (Savino et al 2009), or changing patterns of adipocyte cell size and/or differentiation potential (Morrison and Farmer 2000).…”