Tryptophan, an amino acid in many plant and animal proteins is one of the ingredients needed to make serotonin.
Tryptophan is an excellent natural sedative.
Serotonin is a neurotransmitter that creates feelings of calm and sleepiness.
The trick is to combine foods with some tryptophan and ample carbs.
Since, all amino acids compete for transport to the brain adding carbohydrates increases the release of insulin, which transports other amino acids into muscles.
This leaves tryptophan alone, so it can make its way to the brain and cause sleepiness.Dairy foods are an excellent combination of protein and carbs and they also contain calcium which also aids tryptophan in its conversion. So having warm milk can do the trick if you can't sleep.