Melatonin

Melatonin has been dubbed “the hormone of darkness” as it’s production in the brain increases in low to no light and decreases with the advent of daylight. Melatonin is a naturally occurring molecule, both in humans and in nature. In humans, it is created in the pineal gland located in the brain. The cyclical nature of Melatonin’s release is influenced by the Suprachiasmatic nucleus (SCN) of the hypothalamus in the brain. The SCN supplies the link between the light information received by the retina and the pineal gland. Melatonin has also been found in plants such as rice. This melatonin has been shown to reach and bind to the endogenous melatonin receptors in the brain. The effects of plant melatonin binding to human receptors are unknown.

The melatonin signal forms part of the regulatory system of the circadian rythym.  The production of melatonin is up regulated in darkness and down regulated in light.  Melatonin secretion peaks in the middle of the night and tails off towards daylight.

The modern effects of lighting have changed human’s relationship with the natural day and night cycle.  Historically, humans spent up to eighteen hours in darkness.  With the advent of modern lighting, humans spend barely 8 hours in darkness.  The overall effect has been that of reduced melatonin production.  Reduced melatonin production has been proposed as a likely factor in the higher cancer rates in employees working nights.

Melatonin

There is a theory that plant melatonin can supplement modern decreases in endogenous melatonin.  According to a University of Milan researcher, the melatonin content in wine grapes could help regulate human sleep-wake patterns.

Medically, there seems to be some uses for Melatonin.  It appears useful to counteract sleep disorders related to circadian rhythm disturbances such as jet lag.  Melatonin has also been investigated in treatments of other disorders with mixed results and opinions.