New Study Explains Link Between Gut Health & Depression
A new study suggests that gut health and depression are intrinsically linked by a glitch in neuron chemistry – low serotonin.
The study, conducted in mice, shows that a shortage of serotonin in the neurons of the gut can cause constipation, just as a serotonin shortage in the brain can lead to depression.
The study also found that a treatment that raises serotonin in the gut and the brain may alleviate both conditions.
“Ultimately, many patients with depression are faced with limited treatment options and have to suffer with prominent GI dysfunction,” said study leader Kara Gross Margolis, MD, associate professor of pediatrics at Columbia University Vagelos College of Physicians and Surgeons.
Similarities between the gut and the brain suggest the two conditions may also share a common cause.
“The gut is often called the body’s ‘second brain,'” says Margolis.
“It contains more neurons than the spinal cord and uses many of the same neurotransmitters as the brain. So it shouldn’t be surprising that the two conditions could be caused by the same process.”
Because low levels of serotonin in the brain have been linked to depression and serotonin is also used by neurons in the gut, the researchers studied mice to determine if a serotonin shortage also plays a role in constipation.
The mice used in the study carry a genetic mutation (linked to severe depression in people) that impairs the ability of neurons in the brain and the gut to make serotonin.
The serotonin shortage in the gut, the researchers found, reduced the number of neurons in the gut, led to a deterioration of the gut’s lining, and slowed the movement of contents through the GI tract.
Encouragingly, an experimental drug treatment invented by two of the study’s co-authors, Marc Caron, PhD, and Jacob Jacobsen, PhD, of Duke University, raised serotonin levels in the gut’s neurons and alleviated GI issues in the mice.
Read more: Psychedelics from Toads to Cure Depression?