It is okay to drink a glass of milk before going to sleep, preferably a glass of warm milk, because milk contains an abundance of the amino acid tryptophan, which helps to induce the production of chemicals in the brain like serotonin and melatonin for enhanced sleep, according to BBC Good Food. Drinking milk with a carbohydrate-rich meal before going to sleep will help individuals get a better quality of sleep. In addition, it will also satisfy the recommended two to four servings of milk and other dairy products that each individual needs to consume for a healthy diet.
Eating a carbohydrate-rich meal will cause the body to pump out an excess of insulin, which helps to eliminate the presence of other amino acids from the bloodstream, so that the tryptophan will be even more effective. Milk also contains plentiful quantities of calcium, which aids in bone growth.
Milk contains many other amino acids, which scientists have speculated can help aid in a good night's sleep. Alpha-lactalbumin has a high tryptophan content, and has also been known to increase the ratio of tryptophan to other amino acids that are present in the blood, thus helping to make milk even more effective.