Amylase in human milk.

Amylase activity and isoenzyme pattern were determined in human milk from various stages of lactation and were compared with that in duodenal juice. The activity is high in colostrum and somewhat lower in milk from day 15 to day 90 after delivery. In this period of lactation, human milk contains higher amounts of amylase than duodenal juice from infants aged 1 to 6 months. Low activity was found in milk from 90 days or more after delivery. The amylase is of the salivary type. A pH of 5.3 does not inactivate the amylase; there is considerable human milk amylase activity in duodenal juice after a meal of human milk. Human milk amylase could thus contribute to the breast-fed infant's ability to digest starch.