As if you needed another reason to breastfeed... nighttime nursing causes drowsiness!

You read it right! Yet another example of how Mother Nature knows exactly what she is doing, the milk a mother creates in the evening induces drowsiness in her baby. Nucleotides, the building blocks of DNA, are found in breastmilk and are assumed to be important for tissue development. But that's not all, they have also been implicated to naturally get a baby used to sleeping at night and being awake during the day.

"Cristina Sánchez at the University of Extremadura in Badajoz, Spain, and her colleagues looked at the concentrations of 5'UMP, 5'AMP and 5''GMP – the three nucleotides most strongly associated with sleep and sedation – in the breast milk of 30 healthy mothers who had been breast-feeding for at least 3 months. Samples of milk were collected before each feed over a 24-hour period, with between six and eight samples collected per mother.

They found that concentrations of 5'AMP were highest at the beginning of the night, while levels of 5'GMP and 5'UMP increased as the night wore on. These sedatives were found at much lower concentrations in milk expressed during the day.

She suggests that 5'AMP in breast milk might be fuelling the release of the sleep-promoting neurotransmitter GABA, while 5'GMP is involved in the secretion of melatonin,which helps regulate the natural body clock. 5'UMP is known to promote the amount of both REM and non-REM sleep."

So What Does This Mean for Moms?

Pumping milk during the day and letting Dad bottle feed baby at night is a bad idea. Many parents think letting dad feed the baby at night is a good way for mom to get sleep. Think again! Feeding baby daytime milk in a bottle wouldn't make him drowsy nearly as much as if mom just rolled over and fed him straight from the tap. Basically, this finding proves the point that nature intends for our babies to sleep in bed with us, nursing throughout the night. Babies who are in cribs nurse less during the night and therefore receive less of these nucleotides. Babies who are formula fed are getting the exact same substance all day long, with nothing special to make them sleepy at night.

"Since previous studies have also hinted that bottle-fed infants have more problems sleeping through the night, Sánchez's colleague, Javier Cubero, has been investigating whether sleep-inducing nucleotides could be added to formula milk.

In a separate study, Sánchez and Cubero created a "night-time" milk by adding 5'AMP and 5'UMP to standard formula milk. Infants receiving this milk between 6 pm and 6 am, and normal milk during the day, fell asleep faster and spent longer sleeping than when they drank standard formula milk all the time."

Say What?!

There's a horrible idea if I ever heard one! Sure, adding these sleep inducing nucleotides might be a good way to help formula fed babies with sleep problems... but how many parents will abuse this discovery? A breastfeeding mother can't help the fact that her milk contains more nucleotides at night and less during the day. A formula feeding mother, given the option between AM formula and PM formula, could simply choose to give her child the PM formula whenever she doesn't feel like dealing with him! Now I'm sure most mothers would use it properly, but there are some bad people out there who would jump at the opportunity to make their babies sleep all day. Let's just hope they never start marketing formula with added nucleotides, and keep enjoying the benefits nature stows upon us!