Persistence of human milk proteins in the breast-fed infant

L. A. Davidson, B. Lonnerdal

Research output: Contribution to journalArticlepeer-review

178 Scopus citations


Several proteins in human milk are postulated to have physiological functions in the breast-fed infant. Therefore, survival of human milk proteins after passage through the gastrointestinal tract of the breast-fed infant was investigated. Fecal samples were collected from exclusively breast-fed term infants and milk samples from their mothers. Soluble proteins in the feces were extracted and analyzed for total protein, nitrogen, lactoferrin, secretory IgA, serum albumin and lysozyme. Significant amounts of lactoferrin and secretory IgA were excreted by the infants and this excretion decreased throughout the study period in a trend similar to the decreasing mild concentrations of these proteins. Gel filtraion demonstrated excreted lactoferrin and secretory IgA to be intact. No serum albumin or lysozyme was detected in the fecal extracts. Crossed immunoelectrophoresis showed three human milk proteins to be present in the feces - the third was identified as α1-antitrypsin. Excretion of these proteins indicates the total protein content of human milk is an over-estimation of the protein nutritionally available to the infant.

Original languageEnglish (US)
Pages (from-to)733-740
Number of pages8
JournalActa Paediatrica Scandinavica
Issue number5
StatePublished - 1987

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health


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