Buckwheat contains a high level of tryptophan, an essential amino acid that our body cannot product on its own. In our bodies, tryptophan will change into a brain chemical called serotonin. Serotonin can help improve our sleep.
Turkey, milk, cheese and nuts are some of the foods that contains tryptophan.
Maybe this is why drinking a warm cup of milk at night can make us feel sleepy faster!