**Abstract**

Melatonin is a neurohormone produced and released by the pineal gland. Neurons placed in the eye surface send a signal when the person is exposed to darkness to the suprachiasmatic nuclei and that prompts melatonin release. This biomolecule is in charge of synchronizing body circadian rhythms such as sleep or hunger. Intense light exposure can avoid its release or healthy rhythm. Apart from that, the scientific literature has suggested that melatonin influences immune system, antioxidant capacity, or cell preservation. Moreover, melatonin can be supplied by dietary food such as grapes, dairy or fermented products. Interestingly, some foods contain a significant amount of melatonin and can be considered as good sources of that bioactive molecule. The information in this chapter will cover melatonin dietary sources, biological capacity, related metabolites, and proven benefits in the human body.

**Keywords:** melatonin, diet sources, foods, antioxidant, immune system, cell preservation
