FIGURE 1.

Consumption of dairy products could promote sleep quality by increasing endogenous melatonin production. First, the primary protein sources in dairy, casein and whey, are rich in tryptophan (Trp). Given that Trp is a precursor for the sleep-promoting hormone melatonin (through serotonin), dairy proteins may favorably affect sleep quality by increasing Trp intake. Augmenting the potential role of dairy intake in sleep is its content of micronutrients involved in enzymatic conversions of Trp to serotonin and melatonin. Dairy products are good sources of zinc and magnesium, which serve as cofactors in the production of melatonin from serotonin. Finally, fermented dairy products may exert beneficial effects on sleep by altering gut microbial composition that favor production of serotonin, which can then be converted to melatonin.