Distribution of sialic acids in the milk of spanish mothers of full term
infants during lactation
S. Martin-Sosa, M. J. Martin, L. A. Garcia-Pardo, P. Hueso
J Pediatr Gastroenterol Nutr 39(4), 499-503, 2004
Abstract
OBJECTIVES: The protective effect of human milk against infection is well
known. Several non-immunologic components, including complex carbohydrates, have
been described. The present study was undertaken to determine the sialic acid
distribution in different milk fractions (complex carbohydrates). METHODS: Milk
samples from 12 Spanish women at three different lactational stages (colostrum,
transitional milk and mature milk) were analyzed. Total and glycoprotein-bound,
oligosaccharide-bound, casein-bound, and lipid-bound sialic acids were
determined. RESULTS: Sialic acids from human milk are mainly bound to
oligosaccharides and only a small amount is present bound to glycoproteins or in
the free form. All the fractions analyzed showed a similar trend: sialic acids
decrease rapidly along lactation. Casein-bound sialic acid does not follow this
trend. We detected the presence of an O-acetylated species of N-acetylneuraminic
acid. CONCLUSIONS: In human milk from Spanish women we observed slightly
different values than those previously reported. This could be a result of
population differences but nutritional or methodological aspects can not be
discarded.
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