Long before sleep aids existed in pill form, humans have looked for natural hacks to make bedtime a little easier. Moms for generations have helped their little ones get sleepy and hit the pillow with different foods and drinks, but perhaps no elixir is more famous than a glass of warm milk.
Your mom told you this warm milk would be enough to put you right to sleep, but was she right? And if you *did* find this effective as a child (or even if you still do today), what is it about warm milk that helps you sleep?
The theory goes like this: Cow’s milk contains tryptophan, which is an amino acid that you can find in meat, eggs, and dairy in varying amounts. (Tryptophan is the same reason people believe that Thanksgiving turkey makes you sleepy.)
When you eat tryptophan, your body converts it into niacin, a B vitamin, according to the National Sleep Foundation (NSF). Niacin helps make serotonin (a neurotransmitter), and serotonin affects melatonin levels (a hormone), which regulates your body’s sleep-wake cycle.
In short, tryptophan helps produce the hormone that helps you get sleepy. So eating tryptophan = an easier night of sleep, right?
Here’s the problem: Tryptophan is just one of many amino acids competing to reach the brain. Eating high-protein foods (which are rich with amino acids) means tryptophan can get obstructed by other amino acids, and is thus unable to create serotonin and melatonin.
Tryptophan needs carbs to reach the brain more easily, according to the NSF. If you have tryptophan stored in the body and then eat a carby snack (like whole-grain crackers), the tryptophan may then travel to the brain successfully—giving you that sought-after sleepiness. Here are more bedtime snack ideas to help you sleep.
Wait a second, you might be thinking. Perhaps you used the warm milk trick growing up, or still today, and it has always helped you get sleepy in time to hit the hay. What’s the deal?
Although the tryptophan theory may not be true for warm milk, there’s another phenomenon occurring: For some people, a glass of warm milk might be nostalgic and cozy, which can naturally relax you enough to start feeling sleepy. Plus, the routine of it might signal to your brain that bedtime is approaching.
Even though there may not be anything special about the milk itself to make you drowsy, moms weren’t completely crazy when they taught this trick to their kiddos generation after generation. Check out these other habits of people who always sleep well.