title: Folate and cobalamin status in relation to breastfeeding and weaning in healthy infants.
abstract: BACKGROUND
  Folate and cobalamin status changes markedly during infancy.
  
  
  OBJECTIVE
  We aimed to examine the influence of breastfeeding on folate and cobalamin status in healthy infants.
  
  
  METHODS
  In a longitudinal study, we measured serum folate, cobalamin, holotranscobalamin, holohaptocorrin, methylmalonic acid, and homocysteine at birth and at ages 6, 12, and 24 mo (n = 361, 262, 244, and 224, respectively). Breastfeeding status and nutrient intake were assessed by using questionnaires and 7-d weighed-food records (at 12 mo).
  
  
  RESULTS
  All indexes changed significantly from birth to age 24 mo (P < 0.001). Folate was high until age 6 mo and then declined. At age 6 mo, folate was positively correlated with duration of exclusive breastfeeding (rho = 0.29; P < 0.001). Cobalamin status declined after birth in breastfed but increased in nonbreastfed infants. Thus, holotranscobalamin (pmol/L) was lower in breastfed than in nonbreastfed children at age 6 mo [geometric mean: 37 (95% CI: 33, 40) and 74 (64, 86), respectively], at 12 mo [51 (46, 56) and 76 (70, 82), respectively], and at 24 mo [65 (50, 83) and 90 (85, 97), respectively; P < 0.05 for all]. Complementary feeding did not increase (6 mo) or modestly increased (12 mo) cobalamin status in breastfed children. At 12 mo, cobalamin intake (microg/d), excluding breast milk cobalamin, was lower in breastfed than in nonbreastfed infants [geometric mean: 1.4 (1.3, 1.6) and 2.4 (2.1, 2.6), respectively; P < 0.001]. However, after adjustment for total cobalamin intake, cobalamin status (ie, holotranscobalamin) remained significantly lower in breastfed than in nonbreastfed infants [54 (49, 59) and 70 (64, 78), respectively; P < 0.001].
  
  
  CONCLUSIONS
  Low cobalamin status is a characteristic finding in breastfed children. Reference limits according to age and breastfeeding status should be considered in early childhood.
authors.affiliation: Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway. gry.hay@medisin.uio.no
authors.forename: Gry
authors.initials: G
authors.lastname: Hay
authors.forename: Carole
authors.initials: C
authors.lastname: Johnston
authors.forename: Andrew
authors.initials: A
authors.lastname: Whitelaw
authors.forename: Kerstin
authors.initials: K
authors.lastname: Trygg
authors.forename: Helga
authors.initials: H
authors.lastname: Refsum
mesh_terms: D017677:Age Distribution; D000704:Analysis of Variance; D001942:Breast Feeding; D002675:Child, Preschool; D015930:Diet Records; D005260:Female; D005492:Folic Acid / Q000097:blood*; D006710:Homocysteine / Q000097:blood; D006801:Humans; D007223:Infant; D007227:Infant Nutritional Physiological Phenomena / Q000502:physiology*; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D008764:Methylmalonic Acid / Q000097:blood; D009664:Norway; D009752:Nutritional Status; D012016:Reference Values; D011795:Surveys and Questionnaires; D014805:Vitamin B 12 / Q000097:blood*; D014803:Vitamin B Complex / Q000097:blood; D014886:Weaning
chemical_list: D006710:Homocysteine; D014803:Vitamin B Complex; D008764:Methylmalonic Acid; D005492:Folic Acid; D014805:Vitamin B 12