Serotonin

The Basics

Serotonin is a neurotransmitter. Deficiencies of serotonin are associated with shyness, anxiety, social anxiety, depression, OCD and a ton more. Antidepressants like Prozac work by effectively increasing serotonin levels in your brain. There are many nutrients involved in serotonin synthesis, so it is also possible to raise low serotonin levels nutritionally. Depression is much more likely to be a nutrient deficiency than a prozac deficiency!

Reasons to Suspect

Sources

Tryptophan
Carbohydrates
Zinc
Calcium
Magnesium
Molybdenum
Thiamine
Niacin
Vitamin B6
Folate

Closely Related

Diagram

Inputs/Outputs/Regulators

Start with the amino acid tryptophan. It gets converted to 5-HTP using BH4 and the enzyme tryptophan hydroxylase. 5-HTP is then converted to serotonin using vitamin B6 and the enzyme AAAD.

More Biochemistry

Tryptophan is absorbed from dietary protein. In order to break it down for absorption, adequate stomach acid is necessary. Tryptophan can be diverted for other uses in the body when there is a deficiency. The first is as a glucose substitute for making acetyl coA, which is likely part of why carbohydrate cravings can indicate a serotonin deficiency. The second is synthesis of niacin.

Tryptophan hydroxylase is increased by phosphorylation, especially protein kinase A, which is dependent on cAMP and by calcium and magnesium. BH4 is the cofactor in this reaction. In order to maximize BH4, you need vitamin C, folate and/or niacin, plus molybdenum.

References

Activation of Tryptophan Hydroxylase by Adenosine Triphosphate, Magnesium, and Calcium
Aromatic L-amino acid decarboxylase: a neglected and misunderstood enzyme
http://www.understand-andcure-anxietyattacks-panicattacks-depression.com/5-htp-Melatonin.html