Breast milk should be given to a baby at the same time of day it is expressed, a new study has said.
The levels of the components in breast milk change every 24 hours in response to the needs of the baby. And a new study published in the journal Nutritional Neuroscience shows, for example, how this milk could help newborn babies to sleep.
Breast milk contains various ingredients, such as nucleotides, which perform a very important role in regulating babies' sleep. The new study confirms that the composition of breast milk changes quite markedly throughout the day.
To reach the conclusion, scientists looked for three nucleotides in breast milk (adenosine, guanosine and uridine), which excite or relax the central nervous system, promoting restfulness and sleep, and observed how these varied throughout a 24-hour period.
The milk, collected from 30 women living in Extremadura, was expressed over a 24-hour period, with six to eight daily samples. The highest nucleotide concentrations were found in the night-time samples (8pm to 8am).
"This made us realise that milk induces sleep in babies", Cristina L. Sanchez, lead author of the article and a researcher at the Chrononutrition Laboratory at the University of Extremadura, tells SINC.
"You wouldn't give anyone a coffee at night, and the same is true of milk - it has day-specific ingredients that stimulate activity in the infant, and other night-time components that help the baby to rest", explains Sanchez.
In order to ensure correct nutrition, the baby should be given milk at the same time of day that it was expressed from the mother's breast.
"It is a mistake for the mother to express the milk at a certain time and then store it and feed it to the baby at a different time", points out the researcher.