Mouse Intestine Fluorescence

Serotonin and Obesity: It’s Not Just in Your Head

Maybe it’s not on the tip of every tongue. But serotonin is a bit more familiar than most neurotransmitters. Most people think of it as a “happy hormone” for the central nervous system that becomes depleted in a state of depression. However, The GI system has far more of it than the CNS. And now, new research tells us that in the small intestine, this substance might influence obesity and metabolic health.

Gut versus Brain

Scientists have long known that serotonin in the brain plays a role in eating behaviors. Food intake is higher when levels of this hormone are lower in the brain. But animal studies have suggested a very different relationship between serotonin and obesity in the gut. There, it seems to promote obesity and higher blood sugar levels.

Now, we have confirmation in humans that this is true. Richard Young and colleagues showed that the small intestines of people with obesity produce more serotonin. In fact, the levels were twice as high when compared to normal controls. The gut secretes this hormone in response to sugar and it appears to play a role in developing obesity and diabetes.

A Target for Treatment?

This research is important for two related reasons. First, it gives us more insight into how both obesity and diabetes develop, and why some people are more susceptible than others. In their research, Young et al found more cells that produce serotonin in the small intestines of people with obesity than in those at a normal weight.

With a better understanding of this pathway, we might have a promising new target for treating obesity and diabetes. Says Young:

This has revealed new ways that we may be able to control the release of serotonin from within the gut, and in turn, further improve the outlook for people living with obesity.

Click here for the study and here for more from the University of Adelaide.

Mouse Intestine Fluorescence, photograph © Kelvinh88 / Wikimedia Commons

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March 23, 2018