This dispatch just in from ConscienHealth(1) — well, actually, it was just in back in March — researchers from the University of Adelaide Medical School in Australia have demonstrated some of the importance of intestinal serotonin production in obesity.(2) It turns out that obese people make a lot more serotonin in their intestines and have much higher blood levels of serotonin derived from their intestines.
You may remember serotonin, aka the happy hormone, from the mechanism of action of Prozac and other selective serotonin reuptake inhibitors (SSRIs). This class of anti-anxiety and antidepressant drugs works by increasing serotonin in certain parts of the brain. But 90 percent of the serotonin in your body is produced in cells lining the intestinal tract called enterochromaffin cells.
Serotonin is a small molecule chemically made from the amino acid, triptophan. The chemical name of serotonin is 5-hydroxytryptamine.
These Australian investigators found that human obesity is characterized by an increased capacity to produce and release serotonin from the first part of the small intestine, and serotonin levels are strongly linked to higher body mass, and loss of control of blood sugar. It might in fact be a major driver of obesity and type 2 diabetes. The exciting prospect that this serotonin system may be able to be translated onto future novel treatments for obesity and Type 2 diabetes has prompted Pfizer, the biggest drug manufacturer in the world, to form a collaborative research project with those guys in Adelaide Australia.
Serotonin floating in you bood cannot penetrate the blood brain barrier that isolates the central nervous system from lots of things that might be floating in your blood. So this is probably not going to be about the brain.
But serotonin has so many effects on so many systems in the body. So we need to be careful mucking around with it. Remember the fen-phen diet pills fiasco? That also had to do with this complicated serotonin story.
2. Young RL et al. Augmented capacity for peripheral serotonin release in human obesity. International Journal of Obesity (2018) doi:10.1038/s41366-018-0047-8
John DiTraglia, M.D., is a pediatrician in Portsmouth. He can be reached by email at firstname.lastname@example.org or call 740-354-6605.