Distinct Gut Microbiome Linked with Depression

Distinct Gut Microbiome Linked with Depression

Distinct Gut Microbiome Linked with Depression 1920 1280 Gary Ruelas, D.O., Ph.D.

Over the past decade, researchers have been trying to find links between the human gut microbiome and a variety of diseases and conditions. One study recently discovered a possible connection with our microbial society and major depressive disorder (MDD).

People in the study with MDD had a distinct microbiome compared to those without MDD. By using this “fingerprint,” researchers were able to distinguish between the individuals with MDD and the healthy controls.

Learn more about the study below:

“Microbiome researchers studying MDD have been using an inexact technique called 16S ribosomal RNA sequencing, which can identify bacteria only down to the genus level within a batch of microorganisms, and it excludes viruses. But psychiatrist Shaohua Hu at Zhejiang University School of Medicine in China and his group wanted a more precise picture of the organisms present, so they gathered fecal samples from 236 people, half of whom had been diagnosed with MDD and were unmedicated, and half who were healthy. They sequenced the total genomic DNA of all the bacteria and viruses in the samples, and then used statistical programs to analyze the differences and similarities between people with MDD and healthy controls.

They found that 18 bacterial species were more abundant in people with MDD (mainly belonging to the genus Bacteroides) and 29 were less common (primarily the genera Blautia and Eubacterium) compared to healthy controls. Hu and his team also found three bacteriophages (viruses that infect bacteria) whose levels were different in MDD versus healthy controls, the first time the virome has been studied in MDD. . .

The researchers point out that GABA is a neurotransmitter in the brain, but it’s also made by gut microbes; fecal levels of GABA and certain of its metabolites were decreased in the MDD patients, and the team also found that GABA-related microbial genes were altered in MDD patients, suggesting that microbes modulate GABA levels. Hu and his team hypothesize that this may dysregulate the function of GABA in the brain, and could lead to depressive symptoms.

In addition, the scientists hypothesize that perhaps the increase in Bacteroides bacteria, which induce cytokine production, could increase inflammation, a condition that has been linked to MDD. Also, decreased Blautia, which has been shown to have anti-inflammatory effects, could contribute to MDD. Other studies have also found that when researchers transplant the entire microbiota of a person with MDD into a germ-free rat, the rat starts to behave depressed.”


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Gary Ruelas, D.O., Ph.D.

Dr. Ruelas holds doctoral degrees and is licensed to practice in both medicine and psychology. He approaches his patients by gathering and analyzing data differently from other physician’s moving away from a disease model to a holistic functional model. Read Bio

All articles by : Gary Ruelas, D.O., Ph.D.