Selenium Concentration in Human Milk and the Daily Se Intake by Breast-Fed Infants in the Western Part of Poland

Abstract

Interest in the importance of selenium (Se) in human milk during lactation has increased in recent years. It has been established that Se is specially essential for infants who require this micronutrient for normal growth and development. The aim of our study was to determine the Se concentration in human milk in lactating women in the Western part of Poland and to calculate the daily Se intake of breast-fed infants. The study group comprised 144 lactating women. Most of them were living in cities with over 50,000 residents in the Western part of Poland. The mothers were healthy and had uncomplicated pregnancies and deliveries. All belonged to the low or middle income class. Milk samples were collected in the period between 14 and 28 days after delivery. The daily Se intake by breast-fed infants was calculated on the basis of Se concentration in milk and milk volume consumed in the first month of life. Se concentration was measured by the fluorometric method of Watkinson with 2,3-diaminonaphthalene as a complexing reagent. The mean Se concentration in the milk of lactating women is 10.71 ± 2.87 ng/ml. No significant differences were observed between the provinces; however, the highest values were obtained in the seaside resorts (11.09 ± 2.58 ng/ml) and in some towns of Lower Silesia (11.38 ± 3.13 ng/ml). In the cities of the middle-west part of Poland, the Se level in milk was not significantly lower (10.04 ± 3.03 ng/ml) than in the above-mentioned regions. The calculated mean daily Se intake by breast-fed infants is 6.43 and ranged from 5.64 to 7.39 mg/day. The mean daily Se intake in the region studied by us is lower than the recommended value (10mg/day) established by the US National Research Council. Similar, or even lower values, were calculated in New Zealand (5 mg Se/day), Belgium (7.2), Spain (4.5) and some other countries, where the Se intake was below 6 mg/day. On