May help some people fall asleep faster
A handful of small animal and human studies demonstrate that consuming dairy products like milk and cheese before bed may help some people have a more restful night’s sleep, though the reason why remains unclear.
Most experts agree that milk’s sleep-promoting potential is likely related to specific chemical compounds or the psychological effects of having a soothing bedtime routine — or perhaps a combination of the two.
May promote healthy sleep cycles
Certain compounds in milk — specifically tryptophan and melatonin — may help you fall asleep.
Tryptophan is an amino acid found in a variety of protein-containing foods. It plays an important role in the production of the neurotransmitter known as serotonin .
Serotonin boosts mood, promotes relaxation, and functions as a precursor in the production of the hormone melatonin.
melatonin n. 褪黑素
Melatonin, also known as the sleep hormone, is released by your brain. It helps regulate your circadian rhythm and prepare your body for entering a sleep cycle.
circadian adj. 昼夜节律的，生理节奏的
The role of tryptophan and melatonin in sleep disorders is well established, and studies have found that taking supplements of these compounds may improve sleep and reduce symptoms of anxiety and depression that can crop up at bedtime.
However, there’s currently no evidence to suggest that a single glass of milk contains enough tryptophan or melatonin to significantly influence your body’s natural production of melatonin or to independently treat a disordered sleeping pattern.
Some experts suspect that milk’s potential role as a sleep aid has little to do with its nutritional profile and that it’s instead more closely related to the psychological effect of having a calming bedtime ritual.
Another theory is that drinking warm milk could subconsciously remind you of having milk at bedtime during your early childhood years. These soothing feelings may signal to your brain that it’s time to sleep, making it easier to drift off peacefully.
Still, there’s not enough evidence to guarantee any particular result from adding milk to your bedtime routine.
Milk contains several compounds known to support healthy sleep cycles. Plus, the psychological effects of a bedtime routine that includes milk may improve your ability to fall asleep, but more research is needed.