Serotonin 

A neurotransmitter, serotonin carries signals along and between nerve cells, neurons. Dubbed the happiness hormone serotonin is a chemical regulating some of the circadian rhythms and contributing to happiness and wellbeing. It plays a pivotal role in the regulation of mood, appetite and sleep.    

Serotonin, Melatonin, Melatonin and Circadian Rhythms

Serotonin is manufactured in the brain and the intestines. More than 80% of the body’s serotonin level is found in the gastrointestinal tract and the blood platelets. As serotonin cannot pass through the blood-brain barrier, the serotonin that is used in the brain is produced there. This part of serotonin plays an active role in the sleep and circadian rhythms regulation and is the chemical base for melatonin synthesis in the pineal glands in the brain.

The production of serotonin in the brain is directly proportional to the amount and duration of exposure to bright natural light during the day. The brighter the daylight and the duration of exposure, the more serotonin the brain produces. Total or virtual darkness (using Circadian Eyewear) allow the natural secretion of melatonin by the pineal glands to regulate circadian rhythms associated with night such as sleep. Therefore exposure to bright sunlight during the early hours of the day is extremely important for a good night sleep.

The production of serotonin in the brain is directly proportional to the amount and duration of exposure to bright natural light during the day.

Mental and Physical Health Connected to Serotonin 

Serotonin and the role it plays in mental and physiological health, are the subject of ongoing scientific studies. Several studies have found links between serotonin and bone metabolism, breast milk production, liver regeneration, cell division and sexual function. Serotonin also has some cognitive functions, including memory and learning. Some researchers regard serotonin as a chemical that is responsible for maintaining mood balance, and claim deficit of serotonin leads to depression. In that regard serotonin is dubbed the happiness hormone by some. 

Serotonin also has some cognitive functions, including memory and learning. 

Serotonin Through Food and Supplements

The main building block of serotonin is an essential amino acid called tryptophan which is a major component of protein. Tryptophan is present in most protein based foods or dietary protein supplements. It is plentiful in chocolate, egg whites, oats, dates, dairy products, fish, poultry, red meat, chickpeas, almonds, sunflower sesame, and other edible seeds.

RESEARCH REGARDING SEROTONIN TIED TO CIRCADIAN RHYTHMS 

Research from PubMed 
Serotonin and the regulation of mammalian circadian rhythmicity.

Circadian rhythm of tryptophan, serotonin, melatonin, and pituitary hormones in schizophrenia.

Interactions of the serotonin and circadian systems: nature and nurture in rhythms and blues.

Serotonin phase-shifts the mouse suprachiasmatic circadian clock in vitro.

Research Sources