Approximately 90% of the human body's total serotonin is located in the enterochromaffin cells in the GI tract.
Yes, serotonin is synthesized by the body. In the gut.
Which led me to: Non-pharmacological means of influencing serotonin production.
They cite studies that indicate a clear link between serotonin and positive mood. Positive thought, eating foods with tryptophan precursors, and excercise (especially to the point of exhaustion) all affect production of serotonin. Interestingly, bright lights are important as well, c.f. "light cafes" in Scandanavia. More muscular individuals produce more serotonin!
Coffee / caffeine apparently increases the number of serotonin receptors? Makes the brain more sensitive to serotonin, and also intensifies the let down when the serotonin activity related to caffeine consumption drop off. No cited studies, but an interesting opinion. Apparently vitamin B6 is also important in serotonin synthesis.
So, you may not know this about me, but I have an approximately 10% stake in "woo." I don't strictly require scientific evidence for health claims, as I'm usually willing to try new things out on myself. That may mean that I just ride the placebo effect from cure to cure, but is that such a bad thing? Belief is a pretty big component of health, and that is a studied thing (citation needed ;).
Another thing you may not know is that I have a pretty serious caffeine / hot drink habit. When it's less than
$STUPID_HOT in the room it's hard to work at the computer without a steaming mug of something nearby.
Over the past month, I've weaned myself down to black/green tea & decaf coffee. Oh yeah, and a few energy drinks per week, consumed slowly to space out the dosage. So caffeine isn't gone from my diet, but greatly reduced. In the not-so-recent past I'd usually drink an entire French press of STRONG coffee by myself.
Anecdotally I feel like I'm getting better sleep, and it's easier to get up in the morning. It's hard to explain, but it also feels like exercise has a bigger positive impact — I feel the high more acutely and it fades more slowly.