title: Impact of maternal BMI and sampling strategy on the concentration of leptin, insulin, ghrelin and resistin in breast milk across a single feed: a longitudinal cohort study.
abstract: We tested the hypothesis that there is a positive association between maternal body mass index (BMI) and the concentration of appetite-regulating hormones leptin, insulin, ghrelin and resistin in breast milk. We also aimed to describe the change in breast milk hormone concentration within each feed, and over time.
  
  
  
  Mothers were recruited from the postpartum ward at a university hospital in London. Breast milk samples were collected at the participants' homes.
  
  
  
  We recruited 120 healthy, primiparous, breastfeeding mothers, aged over 18 years. Mothers who smoked, had multiple births or had diabetes were excluded. Foremilk and hindmilk samples were collected from 105 women at 1 week postpartum and 92 women at 3 months postpartum.
  
  
  
  We recorded maternal and infant anthropometric measurements at each sample collection and measured hormone concentrations using a multiplex assay.
  
  
  
  The concentration of leptin in foremilk correlated with maternal BMI at the time of sample collection, at 7 days (r=0.31, p=0.02) and 3 months postpartum (r=0.30, p=<0.00). Foremilk insulin correlated with maternal BMI at 3 months postpartum (r=0.22, p=0.04). Breast milk ghrelin and resistin were not correlated with maternal BMI. Ghrelin concentrations at 3 months postpartum were increased in foremilk compared with hindmilk (p=0.01). Concentrations of ghrelin were increased in hindmilk collected at 1  week postpartum compared with samples collected at 3 months postpartum (p=0.03). A trend towards decreased insulin concentrations in hindmilk was noted. Concentrations of leptin and resistin were not seen to alter over a feed.
  
  
  
  A positive correlation between maternal BMI and foremilk leptin concentration at both time points studied, and foremilk insulin at 3 months postpartum was observed. This may have implications for infant appetite regulation and obesity risk.
authors.affiliation: Section of Neonatal Medicine, Department of Medicine, Chelsea & Westminster Hospital Campus, Imperial College London, London, UK.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Andreas
authors.affiliation: Section of Neonatal Medicine, Department of Medicine, Chelsea & Westminster Hospital Campus, Imperial College London, London, UK.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Hyde
authors.affiliation: Parturition Research Group, Section of Academic Obstetrics & Gynaecology, Department of Medicine, Chelsea & Westminster Hospital, Imperial College London, London, UK.
authors.forename: Bronwen R
authors.initials: BR
authors.lastname: Herbert
authors.affiliation: Section of Neonatal Medicine, Department of Medicine, Chelsea & Westminster Hospital Campus, Imperial College London, London, UK.
authors.forename: Suzan
authors.initials: S
authors.lastname: Jeffries
authors.affiliation: Section of Neonatal Medicine, Department of Medicine, Chelsea & Westminster Hospital Campus, Imperial College London, London, UK.
authors.forename: Shalini
authors.initials: S
authors.lastname: Santhakumaran
authors.affiliation: Section of Neonatal Medicine, Department of Medicine, Chelsea & Westminster Hospital Campus, Imperial College London, London, UK.
authors.forename: Sundhiya
authors.initials: S
authors.lastname: Mandalia
authors.affiliation: Section of Computational and Systems Medicine, Faculty of Medicine, Imperial College London, London, UK.
authors.forename: Elaine
authors.initials: E
authors.lastname: Holmes
authors.affiliation: Section of Neonatal Medicine, Department of Medicine, Chelsea & Westminster Hospital Campus, Imperial College London, London, UK.
authors.forename: Neena
authors.initials: N
authors.lastname: Modi
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D054439:Ghrelin / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007328:Insulin / Q000032:analysis / Q000378:metabolism*; D020738:Leptin / Q000032:analysis / Q000378:metabolism*; D008137:Longitudinal Studies; D008297:Male; D008895:Milk, Human / Q000737:chemistry / Q000378:metabolism*; D050177:Overweight / Q000378:metabolism*; D052243:Resistin / Q000032:analysis / Q000378:metabolism*; D013048:Specimen Handling / Q000379:methods
chemical_list: D054439:Ghrelin; D007328:Insulin; D020738:Leptin; C499624:RETN protein, human; D052243:Resistin
keywords: Ghrelin; Human milk; Insulin; Leptin; Obesity