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Researchers Find Link Between Gut Bacteria And Depression

Two studies in Holland have found a close relationship between depression and gut bacteria. Specific gut bacteria are thought to be linked to depression, but not the cause, and those with more gut bacteria diversity are less likely to suffer from depression.

What are gut bacteria?

Gut bacteria is a generic term for the gut microbiome. The gut microbiome comprises not only gut bacteria but also viruses and fungi.

Of the three researched types, gut bacteria is the most extensively studied. Gut bacteria live in the large intestine, and there are estimated to be up to 1,000 species of bacteria in the large intestine alone. Each bacterium plays a vital role in our physical health, but some also cause disease.

A study in 2018 found that approximately 95% of serotonin, the happy hormone, is produced in the gut. Serotonin is the primary hormone that helps boost happiness and wellbeing and stabilizes mood.

Scientists have long suggested that the relationship between the gut microbiome and mental health contributes to our mood. In 2019, one compelling study discovered that “microbiome (fecal) transplants can transfer symptoms of depression from one animal to another.”

Healthy Life in an Urban Setting project

A project following 23,000 people in Amsterdam is known as the Healthy Life in an Urban Setting (HELIUS). The main focus of this project is to understand the differences between ethnicities living in an urban setting and understand the unfair burden of diseases across the ethnic populations in these settings.

In announcing the findings from two specific studies, Jos Bosch, an associate professor of psychology at the University of Amsterdam who co-wrote both studies, advised that,

Ten years ago, if you’d said there was something linking depression and the microbiome, you’d be carried out with a straitjacket , and now absolutely, it’s very clear there’s a link.”,

Details of the three studies

 Study 1 – correlation between microbiome and depression in ethnic populations

The first study examined the correlation between microbiome and depression in ethnic populations. It followed 3,000 participants from six different ethnicities (Dutch, South-Asian Surinamese, African Surinamese, Ghanaian, Turkish, and Moroccan).

The study found that those with more diverse gut bacteria were less likely to experience depression. The research did not conclude why this was the case and confirmed that lifestyle and diet need further investigation as they could play a role in this finding.

 Study 2 – Understanding if ethnic disparities influenced the gut-mood relationship

The second study focused on understanding if ethnic disparities influenced the gut-mood relationship by analyzing 13 gut bacterial species associated with depression. Two cohorts – 1,054 subjects from the Rotterdam Study and 1,539 subjects from Amsterdam HELIUS, validated the findings.

Dr. Robert Kraaij, the study co-author and a senior research scientist at Erasmus Medical Center Rotterdam in the Netherlands, said that,

People with a higher abundance of Sellimonas, Eggerthella, Lachnoclostridium, and Hungatella reported more depressive symptoms.”

Summing up

To conclude, both study findings are a step forward in understanding the role of gut bacteria and its impact on an individual’s serotonin levels.   The four bacteria identified will need to be researched further.

Long term, it is proposed by many scientists that an analysis of our gut bacteria could lead to early detection of those more susceptible to depression and other diseases. These studies and findings are fascinating, and My Mind News will report any further results.


What do you think about these research findings? Do you believe that there is a link between gut bacteria and depression? Let us know in the comments below. 


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