title: Folate and vitamin B12 in relation to lactation: a 9-month postpartum follow-up study.
abstract: OBJECTIVE
  To investigate the relation between lactation and markers of folate and vitamin B12 (B12) deficiency in women with and without vitamin supplementation.
  
  
  METHODS
  A 9-month follow-up study.
  
  
  METHODS
  Blood samples from 91 women, who gave birth to a single healthy child, were collected 3 weeks, 4 and 9 months postpartum and analysed for circulating level of homocysteine (tHcy), methylmalonic acid (MMA), folate and B12. The participants were categorized as exclusively, partly or not breast-feeding dependent on the degree of lactation 4 months postpartum. During follow-up, lifestyle factors were recorded by structured interviews.
  
  
  RESULTS
  Among 72 exclusively breast-feeding women, the median (10-90% percentile) tHcy was 5.8 (3.1-8.3) micromol/l 3 weeks postpartum, 6.1 (4.1-10.3) micromol/l 4 months postpartum and 5.3 (3.6-8.7) micromol/I 9 months postpartum. At 9 months postpartum, none of the women breast-fed exclusively. No significant change occurred in the concentration of B12 and folate. Exclusively breast-feeding women without vitamin supplementation had higher median tHcy than supplemented exclusively breast-feeding women 4 and 9 months postpartum (7.0 vs 5.4 micromol/l (P < 0.001) and 5.8 vs 4.5 micromol/l (P = 0.003), respectively). Six women had increased (>15 micromol/l) tHcy; four of these were unsupplemented and exclusively breast-feeding.
  
  
  CONCLUSIONS
  We found no overall indication of depletion of the folate and B12 stores during the lactation period in this population. However, folate-supplemented women had lower tHcy and higher folate levels, suggesting a beneficial effect of supplementation with folate throughout lactation.
authors.affiliation: Institute of Public Health, Department of Health Science, Aarhus University, Arhus, Denmark. craha@as.aaa.dk
authors.forename: C H
authors.initials: CH
authors.lastname: Ramlau-Hansen
authors.forename: U K
authors.initials: UK
authors.lastname: Møller
authors.forename: T B
authors.initials: TB
authors.lastname: Henriksen
authors.forename: E
authors.initials: E
authors.lastname: Nexø
authors.forename: J
authors.initials: J
authors.lastname: Møller
mesh_terms: D000328:Adult; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000097:blood*; D005494:Folic Acid Deficiency / Q000097:blood / Q000453:epidemiology; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007774:Lactation / Q000378:metabolism* / Q000502:physiology; D008019:Life Style; D008764:Methylmalonic Acid / Q000097:blood; D009751:Nutritional Requirements; D009752:Nutritional Status; D049590:Postpartum Period / Q000097:blood; D013997:Time Factors; D014805:Vitamin B 12 / Q000008:administration & dosage* / Q000097:blood*; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000453:epidemiology
chemical_list: D006710:Homocysteine; D008764:Methylmalonic Acid; D005492:Folic Acid; D014805:Vitamin B 12