title: Riboflavin levels in maternal milk: the influence of vitamin B2 status during the third trimester of pregnancy.
abstract: OBJECTIVE
  The aim of the present investigation was to study the relationship between riboflavin status during the third trimester of pregnancy and levels of this vitamin in transition milk (days 13 to 14 of lactation) and mature milk (day 40 of lactation).
  
  
  METHODS
  The pregnancies and lactation periods of 57 healthy women between 18 and 35 years of age (27+/-3.7 years) were monitored, vitamin intake during the third trimester was determined by recording the consumption of foods over five days and by registering the quantities provided by dietary supplements. Riboflavin status during this stage of pregnancy was determined via the measurement of the activation of erythrocyte glutathione reductase (EGR) by flavine adenine dinucleotide (FAD). Milk riboflavin levels were determined by fluorometry.
  
  
  RESULTS
  Those subjects with riboflavin intakes below recommended (1.6 mg/day) (Group L) showed lower consumption of milk products (305.2+/-88.5 g/day) than did those with greater intakes (Group H) (507.9+/-137.2 g/day). The consumption of riboflavin containing supplements was very low and was seen only in two H subjects. Transition and mature milk riboflavin levels were significantly higher in H subjects (948.1+/-700.1 nmol/L for transition milk and 993.8+/-436.6 nmol/L for mature milk) than L subjects (574.9+/-258.7 nmol/L for transition milk and 725.4+/-254.3 nmol/L for mature milk). Subjects with alpha-EGR coefficients over 1.2 in the third trimester showed significantly lower mature milk riboflavin levels (704.1+/-241.8 nmol/L) than did subjects with more satisfactory alpha-EGR coefficients (996.4+/-302.9 nmol/L).
  
  
  CONCLUSIONS
  The influence of maternal vitamin B2 status during pregnancy on breast milk riboflavin levels was confirmed.
authors.affiliation: Departamento de Nutrición, Facultad de Farmacia, Universidad Complutense, Madrid, Spain.
authors.forename: R M
authors.initials: RM
authors.lastname: Ortega
authors.forename: M E
authors.initials: ME
authors.lastname: Quintas
authors.forename: R M
authors.initials: RM
authors.lastname: Martínez
authors.forename: P
authors.initials: P
authors.lastname: Andrés
authors.forename: A M
authors.initials: AM
authors.lastname: López-Sobaler
authors.forename: A M
authors.initials: AM
authors.lastname: Requejo
mesh_terms: D000293:Adolescent; D000328:Adult; D001827:Body Height / Q000502:physiology; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology; D015930:Diet Records; D005260:Female; D006801:Humans; D008895:Milk, Human; D011247:Pregnancy; D011263:Pregnancy Trimester, Third / Q000097:blood*; D012256:Riboflavin / Q000097:blood*; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires
chemical_list: D012256:Riboflavin