Warm milk may be soothing, but the jury is out on its soporific qualities. Milk contains a protein called alphalactalbumin, a source of the amino acid tryptophan. This forms serotonin, a neurotransmitter that helps to regulate mood and sleep. Consuming alpha-lactalbumin increases blood levels of tryptophan. However, research shows that a large dose is required to give enough tryptophan for the desired effect. Milk also contains a bioactive peptide, casein hydrolysate, which is thought to have anti-stress properties, while magnesium could help with restless legs. A Dutch trial on 15 women with insomnia suggests that milk may improve sleep, especially when enriched with magnesium and the protein casein hydrolysate.
