Probiotics as a Potential Aid for Depression Symptoms

Study Overview

Recent research suggests that probiotics may assist in alleviating symptoms of depression. A study conducted by a team from the University of Basel, Switzerland, identified a connection between specific gut bacteria and reduced depressive symptoms. The findings were published in Nature Translational Psychiatry.

The Need for Improved Treatments

Current treatments for major depressive disorder (MDD) require enhancement. Depression can be categorized as mild, moderate, or severe, and approximately 66% of individuals undergoing treatment do not experience sufficient relief. Existing options for MDD are often inadequate. Previous studies have established links between gut microbiota—collections of gut bacteria—and instances of depression. Certain bacteria, such as Bacillus coagulans, have been correlated with diminished depressive symptoms in patients suffering from both MDD and irritable bowel syndrome.

Probiotic Efficacy in Reducing Symptoms

The Basel study employed a double-blind randomized controlled trial to assess the relationship between MDD symptoms, gut microbiome, and brain activity. A total of 47 participants were involved, with 21 receiving a daily probiotic dose of 900 billion CFU for 31 days, while 26 in the placebo group received a sugar pill. Evaluations included the Hamilton Rating Scale for Depression (HAM-D), gut microbiome analysis through stool samples, and brain activity monitoring via functional imaging techniques.

Testing occurred at the study’s commencement, on day 31, and four weeks post-treatment. Notably, the treatment group exhibited a 55% remission rate in depressive symptoms, compared to a 40% remission rate in the placebo group, highlighting a significant difference.

Gut Microbiome Changes and Depression Correlation

The study revealed a notable shift in gut microbiome composition between the treatment and placebo groups. Participants receiving probiotics experienced an increase in bacteria from the Lactobacillus family. Statistical analysis indicated a correlation between HAM-D scores and the presence of Lactobacilli, with higher levels associated with lower scores. However, Lactobacillus levels decreased during the four-week follow-up, prompting co-author Anna-Chiara Schaub to suggest that a longer treatment duration may be required for stabilization of intestinal flora.

Brain Activity Findings

At the conclusion of the treatment period, researchers observed decreased activation in the right and left putamen among the treatment group compared to the placebo group, particularly when participants viewed neutral faces. The putamen is implicated in learning, addiction, reward, and motor control. Prior to the study, depressed individuals exhibited greater activation in these areas than their healthy counterparts. The research team posits that these brain regions may be linked to depressive symptoms, although the underlying mechanisms remain unclear.

Future Research Directions

While the study demonstrates promising results, the precise mechanisms connecting depression, the gut microbiome, and brain activity require further exploration. Researchers aim to develop a targeted probiotic mixture to alleviate depressive symptoms. It is crucial to emphasize that probiotics should not be viewed as standalone treatments for depression. Individuals experiencing depression should consult their healthcare provider for appropriate guidance.

References

1. Schaub, A. et al. (2022). Clinical, gut microbial and neural effects of a probiotic add-on therapy in depressed patients: a randomized controlled trial. Translational Psychiatry; 12(227). Doi: 10.1038/s41398-022-01977-z.
2. Rush, A.J. et al. (2006). Acute and longer-term outcomes in depressed outpatients requiring one or several treatment steps: a STAR*D report. American Journal of Psychiatry; 163: 1905-1917.
3. Ng, Q.X. et al. (2018). A meta-analysis of the use of probiotics to alleviate depressive symptoms. Journal of Affective Disorders; 228: 13-19.
4. Majeed, M. et al. (2018). Bacillus coagulans MTCC 5856 for the management of major depression with irritable bowel syndrome: a randomised, double-blind, placebo controlled, multi-centre, pilot clinical study. Food & Nutrition Research; 62. Doi: 10.29219/fnr.v62.1218.
5. Pinto-Sanchez, M.I, et al. (2017). Probiotic Bifidobacterium longum NCC3001 reduces depression scores and alters brain activity: a pilot study in patients with irritable bowel syndrome. Gastroenterology; 153: 448.
6. Jacobs, A. (2022). Good bacteria to tackle depression. EurekAlert! Accessed on Jun. 16, 2022. Retrieved from https://www.eurekalert.org/news-releases/955452.
7. Ghandili, M. and S. Munakomi. (2022). Neuroanatomy, Putamen [Internet]. Treasure Island, Florida: StatPearls Publishing. Accessed on Jun. 18, 2022. Retrieved from the National Library of Medicine, National Center for Biotechnology Information, https://www.ncbi.nlm.nih.gov/books/NBK542170/#:~:text=The%20putamen%20is%20involved%20in,%2C%20cognitive%20functioning%2C%20and%20addiction.
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