Microbiome composition found to influence depression

Microbiome composition influences depression
Beta-diversity is linked with ethnic differences in depressive symptom scores. A Beta-diversity predicting PHQ9 depression. It presents results of linear regression analyses that model β-diversity as a predictor of depressive symptom levels. Panel (A) horizontal bars present ΔR2 after progressive adjustments for confounders (models 1a to 3), and respectively without and with ethnicity included in each regression model. B Ethnicity predicting PHQ9 depression. It presents results of linear regression in which β-diversity is modeled as a mediator of the association between ethnicity and depressive symptom levels (see lower figure). Bars present ΔR2 the prediction of PHQ9 by ethnicity after progressive adjustments (models 1a to 3). Blue bars present ΔR2 without β diversity incorporated as a mediator in the model, and the orange bars present ΔR2 when mediation is assumed. The % in the table (right) indicate the attenuation of the direct effect by mediation. Regression models: We used two-sided linear regression analyses, no adjustments were made for multiple comparisons. Model 1a adjusted for age and gender; Model 1b added education; Model 2 further added behavioral factors (alcohol, smoking, exercise, BMI); Model 3 added GI disease, Diabetes, PPI use, Recent antibiotics, Diarrhea. All ΔR2 p ≤ 0.001, except for ethnicity-inclusive Model 3 (p = 0.023). Credit: Nature Communications (2022). DOI: 10.1038/s41467-022-34504-1

Our microbiome, the billions of microorganisms that live in and on our bodies, control many important bodily functions, including those in our brain. Recent research by Amsterdam UMC, the University of Amsterdam and Erasmus MC delivers the most extensive evidence to date of a relationship between the composition of the microbiome and instances of depression. This composition also plays a role in the differing rates of depression across different ethnic groups.

These studies, based partly on data from the HELIUS study, appear today as a double publication in Nature Communications.

A wide variety of microorganisms, such as bacteria, viruses and yeasts, live on and in the human body. All those microorganisms together are called the microbiome. The microbiome is necessary for optimal physical functioning; for example, through the production of essential nutrients and protection against pathogens. Disturbances in the microbiome increase the risk of numerous diseases. For example, there is increasing evidence that variousbrain diseases are also related to disturbances in the microbiome.

Role of the microbiome

These results come from the most extensive study into the relationship between the microbiome and , involving 3,211 participants from the HELIUS study, led by professor Max Nieuwdorp. This research shows a clear relationship between the composition of the microbiome and depression.

A microbiome containing less diverse bacteria, or in which certain are underrepresented, was associated with having depression or more depressive symptoms. This association was as strong as established risk factors for depression such as smoking, alcohol consumption, a lack of exercise and being overweight. Influencing the microbiome may therefore be hugely relevant for the treatment of depression.

"Now that we know which disturbances in the microbiome are significant for depression, this opens up new possibilities for treatment and prevention. Which is urgently needed," says Anja Lok, psychiatrist and researcher at the Department of Psychiatry at Amsterdam UMC.

Ethnic differences

Previous research from the HELIUS study has illustrated ethnic differences in both the composition of the microbiome and the occurrence of depression. But until now no connection between the two had been found.

Researcher Jos Bosch, from the University of Amsterdam's Department of Psychology, says, "The substantial ethnic differences in depression do indeed appear to be related to in the microbiome. We don't know exactly why this is yet. This association was not caused by differences in lifestyle such as smoking, drinking, weight or exercise, and merits further investigation. For example, diet could play a role." This is the first study to show that the disparity in depression between is related to the composition of the microbiome.

Confirmation by Rotterdam study

It is important to determine whether the relationships found between the and depression can be confirmed by other studies. In the second article in Nature Communications, by researchers from Erasmus MC, the data from the HELIUS study and ERGO study were compared. This comparison confirmed a consistent association between twelve groups of bacteria and the occurrence of depression and offered an explanation: the twelve bacterial groups produce substances such as glutamate, butyrate, serotonin and gamma amino butyric acid.

These so-called "neurotransmitters" play an important role in depression. "These results therefore clearly provide direction for future research into possible treatments, such as the use of probiotics, prebiotics and synbiotics or fecal microbiota transplantation as well as changes to lifestyle and diet," says Anja Lok.

More information: Jos A. Bosch et al, The gut microbiota and depressive symptoms across ethnic groups, Nature Communications (2022). DOI: 10.1038/s41467-022-34504-1

Djawad Radjabzadeh et al, Gut microbiome-wide association study of depressive symptoms, Nature Communications (2022). DOI: 10.1038/s41467-022-34502-3

Journal information: Nature Communications

Citation: Microbiome composition found to influence depression (2022, December 7) retrieved 25 March 2023 from https://phys.org/news/2022-12-microbiome-composition-depression.html
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