title: Free glutamine and glutamic acid increase in human milk through a three-month lactation period.
abstract: BACKGROUND
  Previous short observational studies on the free amino acid (FAA) content of human milk have shown that glutamine and glutamic acid increase in the first 4 to 6 weeks of life.
  
  
  METHODS
  Changes in human milk content of free amino acids (FAAs) was determined at colostrum, 1 month, and 3 months of lactation in 16 healthy lactating women after delivery of full-term infants. Milk was collected at the end of each feeding (hindmilk) during 24 hours.
  
  
  RESULTS
  Glutamic acid and taurine were the most abundant FAAs at colostrum. Although taurine remained stable throughout lactation, glutamic acid (the prevalent FAA) and glutamine increased approximately 2.5 and 20 times, respectively, with progressing lactation representing more than 50% of total FAA at 3 months. The content of essential FAA was also stable, so the change in total FAA content was almost entirely due to the changes in glutamic acid and glutamine.
  
  
  CONCLUSIONS
  Breast-fed infants are supplied with progressively increasing amounts of glutamine and glutamic acid throughout lactation. The increasing intake of glutamic acid and glutamine could benefit breast-fed infants with molecules that are likely to protect the enteral mucosa and act as neurotransmitters and as a source of nitrogen.
authors.affiliation: Department of Pediatrics, San Paolo Hospital, Milan, Italy. agostoc@tin.it
authors.forename: C
authors.initials: C
authors.lastname: Agostoni
authors.forename: B
authors.initials: B
authors.lastname: Carratù
authors.forename: C
authors.initials: C
authors.lastname: Boniglia
authors.forename: A M
authors.initials: AM
authors.lastname: Lammardo
authors.forename: E
authors.initials: E
authors.lastname: Riva
authors.forename: E
authors.initials: E
authors.lastname: Sanzini
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000008:administration & dosage / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D003126:Colostrum / Q000737:chemistry*; D005260:Female; D005470:Fluorometry; D018698:Glutamic Acid / Q000008:administration & dosage / Q000032:analysis*; D005973:Glutamine / Q000008:administration & dosage / Q000032:analysis*; D006128:Growth; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007774:Lactation / Q000502:physiology*; D008137:Longitudinal Studies; D008895:Milk, Human / Q000737:chemistry*; D013997:Time Factors
chemical_list: D000596:Amino Acids; D005973:Glutamine; D018698:Glutamic Acid