Re: The 5-HTP for sleep question - A Word of Caution

[Guest guest]

Hi All;

I'd just like to add a word of caution about taking 5-

hydroxytryptophan. It can induce diarrhea! This is because it is

converted to 5-hydroxytryptamine (serotonin) in the gut (by a

decarboxylase enzyme present there). The 5-hydroxytryptamine

(serotonin) then binds to receptors, and increases gastointestinal

motility when it is present in excess:

Neuropharmacology 55: 1072-1080 (2008)

Serotonin and GI clinical disorders.

Spiller R

Wolfson Digestive Diseases Centre, C Floor South Block, University

Hospital, Clifton Boulevard, Nottingham, NG7 2UH, United Kingdom.

robin.spiller@...

Serotonin is widely distributed throughout the gut within both the

enteric nerves and enterochromaffin (EC) cells. EC cells are located

in the gut mucosa with maximal numbers in the duodenum and rectum

where they act as signal transducers, responding to pressure and

luminal substances both bacterial and dietary. Activation leads to

serotonin release which acts on a range of receptors on mucosal

afferent and myenteric interneurones to initiate secretomotor

reflexes. These cause nausea and vomiting as well as intestinal

secretion, propulsion and if pronounced, diarrhoea. Inflammation in

animal models acts via T lymphocytes to increase EC cell numbers and

mucosal serotonin (5-HT) content while inflammatory cytokines

decrease serotonin transporter (SERT) function. Inflammation due to

coeliac disease and following gastrointestinal infection increases

mucosal 5-HT availability by a combination of increased EC cells and

depressed SERT. Irritable bowel syndrome (IBS) developing after

gastrointestinal infection and IBS with diarrhoea is associated with

excess 5-HT. The associated diarrhoeal symptoms respond well to 5-HT

(3) receptor antagonists. These drugs also inhibit the nausea and

vomiting occurring in patients undergoing chemotherapy which cause a

marked increase in release of 5-HT as well as other mediators. Other

conditions including IBS-C and constipation may have inadequate 5-HT

release and benefit from both 5-HT(3) and 5-HT(4) receptor agonists.

PMID: 18687345.

Please talk with your doctor(s) before taking any 5-

hydroxytryptophan. You don't want to be making your inflammatory

bowel disease worse!

Best regards,

Dave

(father of (23); PSC 07/03; UC 08/03)