2'-fucosyllactose: an abundant, genetically determined soluble glycan present in human milk

Nutr Rev. 2013 Dec;71(12):773-89. doi: 10.1111/nure.12079. Epub 2013 Nov 18.


Lactose is the preeminent soluble glycan in milk and a significant source of energy for most newborn mammals. Elongation of lactose with additional monosaccharides gives rise to a varied repertoire of free soluble glycans such as 2'-fucosyllactose (2'-FL), which is the most abundant oligosaccharide in human milk. In infants, 2'-FL is resistant to digestion and reaches the colon where it is partially fermented, behaving as soluble prebiotic fiber. Evidence also suggests that portions of small soluble milk glycans, including 2'-FL, are absorbed, thus raising the possibility of systemic biological effects. 2'-FL bears an epitope of the Secretor histo-blood group system; approximately 70-80% of all milk samples contain 2'-FL, since its synthesis depends on a fucosyltransferase that is not uniformly expressed. The fact that some infants are not exposed to 2'-FL has helped researchers to retrospectively probe for biological activities of this glycan. This review summarizes the attributes of 2'-FL in terms of its occurrence in mammalian phylogeny, its postulated biological activities, and its variability in human milk.

Keywords: 2′-fucosyllactose; breastfeeding; evolution; glycans; milk; oligosaccharides; prebiotic.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Digestion
  • Fermentation
  • Fucosyltransferases / metabolism
  • Humans
  • Infant
  • Infant Nutritional Physiological Phenomena / physiology
  • Infant, Newborn
  • Milk, Human / chemistry*
  • Milk, Human / metabolism
  • Polysaccharides / analysis
  • Prebiotics
  • Solubility
  • Trisaccharides / analysis*
  • Trisaccharides / metabolism
  • Trisaccharides / physiology*


  • Polysaccharides
  • Prebiotics
  • Trisaccharides
  • Fucosyltransferases
  • 2'-fucosyllactose