A multinational study of α-lactalbumin concentrations in human milk

Joan G. Jackson, Derek B. Janszen, Bo Lonnerdal, Eric L. Lien, Kathryn P. Pramuk, Charles F. Kuhlman

Research output: Contribution to journalArticlepeer-review

60 Scopus citations


α-Lactalbumin, a 14-kD protein, plays a central biochemical role in the mammary gland as the regulatory subunit of lactose synthase, and also plays a nutritional role for the rapidly growing neonate as the protein in highest concentration in human milk. The current study was undertaken to better characterize α-lactalbumin concentrations in human milk from a variety of countries. Mature human milk (lactation duration ≥1 month) was collected from at least 50 women from nine different countries on five continents. α-Lactalbumin concentration was determined by HPLC. The mean ± SD for 452 samples was 2.44 ± 0.64 g/L. The mean value of the samples from the United States was significantly higher than that from any other country, and the mean in Mexico was significantly lower than that from every country except China and Canada. α-Lactalbumin concentration decreased with increasing duration of lactation and was positively correlated with total nitrogen. On average, α-lactalbumin contributed 16% of the total nitrogen content of human milk and consequently an important part of the amino acid content.

Original languageEnglish (US)
Pages (from-to)517-521
Number of pages5
JournalJournal of Nutritional Biochemistry
Issue number9
StatePublished - Sep 2004


  • HPLC
  • Lactalbumin
  • Mature human milk
  • Multi-country variation

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology, Diabetes and Metabolism


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