Lactose content of breast milk among lactating women in Latvia

Human milk is the best nutrient source providing everything for the infant's development. Lactose, after the fat, is the second most energy-dense macronutrient found in the breast milk but its concentration can be affected by factors like mother’s current body mass index (BMI), birth weight of an infant, duration of lactation, etc. The aim of this study was to determine lactose content in mature breast milk among lactating women in Latvia and factors affecting it. The preliminary study was carried out from November 2016 to February 2017. In total, 28 mature milk samples pooled within 24 h were collected from mothers whose off springs had reached the age of at least two months. Participants (28 mothers with singleton deliveries of 13 male and 15 female infants) were 26 to 39 years old with an average BMI 21.85±2.69. Personal information including birth weight and age of an infant, breastfeeding method (exclusive, mixed) and milk expression manner (by hand or using breast pump) was recorded. Lactose content was determined by ISO 22662:2007. Mean lactose concentration was 6.53±0.34% which is comparable to data obtained from other studies. Although breast milk composition is variable and changes according to the needs of an offspring, no significant difference in lactose content was found for age (2 to 21 months), gender or birth weight (3.53±0.63 kg) of an infant (p>0.05). None of the recorded maternal characteristics influenced lactose’s content in milk. Also milk expression or breastfeeding method did not affect it. Preliminary results show that lactose concentration is kept relatively constant in human milk, however more samples need to be analysed for further conclusions.