title: Vitamin D content in human breast milk: a 9-mo follow-up study.
abstract: BACKGROUND
  Parents are advised to avoid the direct sun exposure of their newborns. Therefore, the vitamin D status of exclusively breastfed newborns is entirely dependent on the supply of vitamin D from breast milk.
  
  
  OBJECTIVE
  We explored concentrations of ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3) (vitamin D) and 25-hydroxivitamin D2 plus D3 (25-hydroxyvitamin D [25(OH)D]) in foremilk and hindmilk during the first 9 mo of lactation and identified indexes of importance to the concentrations.
  
  
  METHODS
  We collected blood and breast-milk samples from mothers at 2 wk (n = 107), 4 mo, (n = 90), and 9 mo (n = 48) postpartum. Blood samples from infants were collected 4 and 9 mo after birth. We measured concentrations of vitamin D metabolites in blood and milk samples with the use of liquid chromatography-tandem mass spectrometry.
  
  
  RESULTS
  Concentrations of vitamin D and 25(OH)D correlated significantly and were higher in hindmilk than in foremilk. Milk concentrations were also correlated with maternal plasma 25(OH)D concentrations. In foremilk and hindmilk, concentrations were a median (IQR) of 1.35% (1.04-1.84%) and 2.10% (1.63-2.65%), respectively, of maternal plasma 25(OH)D concentrations (P < 0.01). Milk concentrations showed a significant seasonal variation. Mothers who were taking vitamin D supplements had higher concentrations than did nonusers. Medians (IQRs) of infant daily intake through breast milk of vitamin D and 25(OH)D were 0.10 μg (0.02-0.40 μg) and 0.34 μg (0.24-0.47 μg), respectively, which were equal to a median (IQR) antirachitic activity of 77 IU/d (52-110 IU/d).
  
  
  CONCLUSIONS
  The supply of vitamin D from breast milk is limited. Exclusively breastfed infants received <20% of the daily dose recommended by the Institute of Medicine for infants during the first year of life. This trial was registered at clinicaltrials.gov as NCT02548520.
authors.affiliation: Departments of Endocrinology and Internal Medicine and.
authors.forename: Susanna
authors.initials: S
authors.lastname: við Streym
authors.affiliation: Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark; and.
authors.forename: Carsten S
authors.initials: CS
authors.lastname: Højskov
authors.affiliation: Departments of Endocrinology and Internal Medicine and.
authors.forename: Ulla Kristine
authors.initials: UK
authors.lastname: Møller
authors.affiliation: Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark; and.
authors.forename: Lene
authors.initials: L
authors.lastname: Heickendorff
authors.affiliation: Clinical Institute, Aalborg University, Aalborg, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Vestergaard
authors.affiliation: Departments of Endocrinology and Internal Medicine and.
authors.forename: Leif
authors.initials: L
authors.lastname: Mosekilde
authors.affiliation: Departments of Endocrinology and Internal Medicine and lars.rejnmark@rm.dk.
authors.forename: Lars
authors.identifier: http://orcid.org/0000-0002-2152-4247
authors.initials: L
authors.lastname: Rejnmark
mesh_terms: D000328:Adult; D001942:Breast Feeding; D002112:Calcifediol / Q000378:metabolism; D002762:Cholecalciferol / Q000378:metabolism; D019587:Dietary Supplements; D002149:Energy Intake; D004872:Ergocalciferols / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007227:Infant Nutritional Physiological Phenomena; D007231:Infant, Newborn; D007774:Lactation / Q000378:metabolism*; D039382:Maternal Nutritional Physiological Phenomena; D008895:Milk, Human / Q000378:metabolism*; D049590:Postpartum Period; D011247:Pregnancy; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism* / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000097:blood / Q000209:etiology / Q000517:prevention & control; D055815:Young Adult
chemical_list: D004872:Ergocalciferols; D014807:Vitamin D; D002762:Cholecalciferol; C104450:25-hydroxyvitamin D; D002112:Calcifediol
keywords: breastfeeding; infants; nutrition; rickets; vitamin D