Vitamin D content in human breast milk: a 9-mo follow-up study1

• Published in: The American journal of clinical nutrition 2016-01, Vol.103 (1), p.107-114
• Main Authors: við Streym, Susanna, Højskov, Carsten S, Møller, Ulla Kristine, Heickendorff, Lene, Vestergaard, Peter, Mosekilde, Leif, Rejnmark, Lars
• Format: Article
• Language: English
• Subjects: breastfeeding; infants; nutrition; rickets; vitamin D
• ISSN: 0002-9165; 1938-3207
• DOI: 10.3945/ajcn.115.115105

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. Objectives: 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. Design: 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