Milk really can aid a good night’s sleep

A WARM glass of milk has long been used by parents to settle toddlers before bed. But new research has suggested that it is not just an old wives’ tale and the bedtime drink really does help ensure a good night’s sleep.

It is estimated that more than a third of Britons struggle to get to sleep on a weekly basis. Sedatives such as benzodiazepines and zolpidem are commonly prescribed to treat insomnia, while sales of cannabis oils as a natural remedy have surged over the past year.

However, many of these sedatives come with a host of side-effects including memory problems, confusion and muscle weakness as well as being highly addictive for some users. They work by activating the GABA receptor, a protein in the brain that suppresses nerve signalling and slows down brain activity.

In an attempt to find alternatives, scientists, funded by the National Natural Science Foundation of China, discovered that naturally-sourced peptides found in cow’s milk cause the same effect of drowsiness by binding the GABA receptor. The milk contains tryptophan and other peptides that relieve stress and encourage sleep.

Together with a digestive enzyme called trypsin, they create a highly effective mixture of sleep-enhancing peptides, known as casein tryptic hydrolysate (CTH). Within this mixture, scientists discovered that a specific peptide, known as alpha-casozepine (alphaczp), could be responsible for causing these effects.

Together with colleagues, the study’s authors, Prof Lin Zheng and Prof Mouming Zhao, wondered if they could find more powerful, sleep-enhancing peptides in CTH. To test this, researchers compared the effects of CTH and alpha-czp in sleep tests using mice and found that CTH showed more promising sleep-enhancing properties than just alpha-czp alone.

This finding suggested that other properties promoting sleep exist in the CTH mixture. The researchers were able to observe a specific natural peptide, called YPVEPF, which increased the number of mice that fell asleep quickly by about 25 per cent, while improving their sleep duration by more than a staggering 400 per cent, compared with the control group.