ALKALINE PHOSPHATASE ACTIVITY IN HUMAN MILK DURING THE FIRST MONTH OF LACTATION

Human milk is the main source of nutrients for a child during the first months of life. Alkaline phosphatase (EC 3.1.3.1) is a very important enzyme in clinical chemistry because of its activity in various tissues and biological fluids, being an indicator of physiological or diseased states. Milk contains several phosphatases, the principal ones being alkaline and acid phosphomonoesterases which have no known function or significance in milk, and have been studied extensively so far.The objective of the present study was to determine the alkaline phosphatase activity and concentration of inorganic phosphorus (P) in colostrum and mature milk obtained from nursing mothers.Our longitudinal biochemical analysis showed that alkaline phospha-tase activities decreased from the 1st and the 2nd day of lactation (colostrum) to the end of the first month of lactation (at day 30). The amount of inorganic phosphates from colostrum increased to the end of the first month (at day 30) of lactation. The alteration between colostral and mature milk alkaline phospha-tase activity may be a consequence of the ALP transfer from the blood of mother into the colostrum and milk during breastfeeding.The concentration of nutrients in colostrum and mature milk suffers alterations, including a decrease in alkaline phosphatase activity and an increase in P, probably in order to satisfy the requirements of the nursing infant.