Altered gut microbiota and inflammatory markers in depression: A cross-sectional study.

Saswati Sucharita  Pati; Sudhansu Priyadarshini  Biswal; Duryodhan  Sahoo; Jharana  Mahanta

doi:10.51168/sjhrafrica.v6i6.1911

Authors

Saswati Sucharita Pati Assistant Professor, Department of Psychiatry, Dharanidhar Medical College & Hospital, Keonjhar, Odisha, India
Sudhansu Priyadarshini Biswal Assistant Professor, Department of Microbiology, Dharanidhar Medical College & Hospital, Keonjhar, Odisha, India
Duryodhan Sahoo Assistant Professor, Department of Biochemistry, Dharanidhar Medical College & Hospital, Keonjhar, Odisha, India
Jharana Mahanta Assistant Professor, Department of Microbiology, Dharanidhar Medical College & Hospital, Keonjhar, Odisha, India

DOI:

https://doi.org/10.51168/sjhrafrica.v6i6.1911

Keywords:

Depression, Gut Microbiota, Inflammatory Markers, Dysbiosis, Gut–Brain Axis

Abstract

Background:
Depression is a multifactorial mental health disorder influenced by psychological, biological, and environmental factors. Emerging evidence highlights the role of the gut–brain axis, particularly gut microbiota and inflammatory responses, in the pathophysiology of depression.

Aim:

To investigate alterations in gut microbiota composition and their association with systemic inflammatory markers in individuals diagnosed with depression.

Methods:

A cross-sectional observational study was conducted over one year, involving 100 participants 50 with clinically diagnosed depression and 50 healthy controls. Stool and blood samples were collected to analyze gut microbiota via 16S rRNA sequencing and inflammatory markers (CRP, IL-6, TNF-α) via ELISA. Data were analyzed using SPSS version 23.0.

Results:

Participant characteristics included religion and educational status, with 68% of participants identifying as Hindu, 22% as Muslim, and 10% as others; 54% had completed secondary education, while 46% had higher education. Depressed individuals showed significantly elevated levels of CRP (6.2 ± 2.1 mg/L), IL-6 (11.4 ± 3.8 pg/mL), and TNF-α (19.7 ± 6.5 pg/mL) compared to controls (p < 0.001). Gut microbiota analysis revealed a reduction in beneficial bacteria (Lactobacillus and Bifidobacterium) and an increase in Proteobacteria and Firmicutes/Bacteroidetes ratio in the depression group. Significant negative correlations were observed between beneficial bacteria and inflammatory markers (Lactobacillus vs. CRP (r = –0.52, p < 0.001) and Bifidobacterium vs. TNF-α (r = –0.44, p = 0.004)), indicating a potential link between microbial dysbiosis and systemic inflammation in depression.

Conclusion:

The findings suggest that depression is associated with gut microbiota imbalance and elevated inflammatory markers. Dysbiosis may contribute to systemic inflammation reinforcing the role of the gut–brain–immune axis in depression's pathogenesis.

Recommendations:

Future longitudinal studies should explore microbiome-based therapeutic interventions, such as probiotics or dietary modulation, as adjunctive treatments for depression. Incorporating gut health screening in mental health assessments may enhance holistic management.

References

World Health Organization. Depression [Internet]. 2023 [cited 2025 May 22]. Available from: https://www.who.int/news-room/fact-sheets/detail/depression

Malhi GS, Mann JJ. Depression. Lancet. 2018 Nov 24;392(10161):2299-312. https://doi.org/10.1016/S0140-6736(18)31948-2

Cryan JF, O'Riordan KJ, Cowan CSM, Sandhu KV, Bastiaanssen TFS, Boehme M, et al. The microbiota-gut-brain axis. Physiol Rev. 2019 Oct;99(4):1877-2013.

Morais LH, Schreiber HL, Mazmanian SK. The gut microbiota-brain axis in behaviour and brain disorders. Nat Rev Microbiol. 2021 Apr;19(4):241-55. https://doi.org/10.1038/s41579-020-00460-0

Simpson CA, Dias C, Fernandes M, Boyle C, Morais LH. The gut microbiota in anxiety and depression - A systematic review. Clin Psychol Rev. 2021 Apr; 88:102072. https://doi.org/10.1016/j.cpr.2020.101943

Liu RT, Walsh RFL, Sheehan AE. Prebiotics and probiotics for depression and anxiety: A systematic review and meta-analysis of controlled clinical trials. Neurosci Biobehav Rev. 2019 May;102:13-23. https://doi.org/10.1016/j.neubiorev.2019.03.023

Valles-Colomer M, Falony G, Darzi Y, Tigchelaar EF, Wang J, Tito RY, et al. The neuroactive potential of the human gut microbiota in quality of life and depression. Nat Microbiol. 2019 Jun;4(4):623-32. https://doi.org/10.1038/s41564-018-0337-x

Osimo EF, Baxter LJ, Lewis G, Jones PB, Khandaker GM. Prevalence of low-grade inflammation in depression: a systematic review and meta-analysis of CRP levels. Psychol Med. 2019 Oct;49(12):1958-70. https://doi.org/10.1017/S0033291719001454

Dantzer R, O'Connor JC, Freund GG, Johnson RW, Kelley KW. From inflammation to sickness and depression: when the immune system subjugates the brain. Nat Rev Neurosci. 2021 Jul;22(7):471-84.

Kazemi A, Noorbala AA, Djafarian K, Shab-Bidar S. Effect of probiotic and prebiotic supplementation on depressive symptoms: A systematic review and meta-analysis. Clin Nutr. 2019 Jun;38(3):964-73.

Huang R, Wang K, Hu J. Effect of fecal microbiota transplantation on symptoms of depression: A systematic review. Front Psychiatry. 2022 Jan;13:812605. https://doi.org/10.3389/fpsyt.2022.695481

Liu P, Liu Z, Wang J, Wang J, Gao M, Zhang Y, et al. Immunoregulatory role of the gut microbiota in inflammatory depression. Nat Commun. 2024;15: Article no. 47273. https://doi.org/10.1038/s41467-024-47273-w

Jia X, Wang J, Ren D, Zhang K, Zhang H, Jin T, Wu S. Impact of the gut microbiota-Th17 cell axis on inflammatory depression. Front Psychiatry. 2024;15: Article no. 1509191. https://doi.org/10.3389/fpsyt.2024.1509191

Chen Y, Le D, Xu J, Jin P, Zhang Y, Liao Z. Gut microbiota dysbiosis and inflammation dysfunction in late-life depression: an observational cross-sectional analysis. Neuropsychiatr Dis Treat. 2024;20:399-414. https://doi.org/10.2147/NDT.S449224

Liu P, Jing L, Guo F, Xu Y, Cheng J, Liu S, et al. Characteristics of gut microbiota and its correlation with hs-CRP and somatic symptoms in first-episode treatment-naive major depressive disorder. J Affect Disord. 2024; Apr; Article ID 011. https://doi.org/10.1016/j.jad.2024.04.011

Huang L, Ma Z, Ze X, Zhao X, Zhang M, Lv X, et al. Gut microbiota decreased inflammation induced by chronic unpredictable mild stress through affecting NLRP3 inflammasome. Front Cell Infect Microbiol. 2023;13: Article no. 1189008. https://doi.org/10.3389/fcimb.2023.1189008

Tan Y, Xu M, Lin D. Review of research progress on intestinal microbiota based on metabolism and inflammation for depression. Arch Microbiol. 2024;206(4):146. https://doi.org/10.1007/s00203-024-03866-z

Dabboussi N, Debs E, Bouji M, Rafei R, Fares N. Balancing the mind: toward a complete picture of the interplay between gut microbiota, inflammation and major depressive disorder. Brain Res Bull. 2024;216: Article no. 111056. https://doi.org/10.1016/j.brainresbull.2024.111056

Dubois T, Zdanowicz N, Jacques D, Lepièce B, Jassogne C. Microbiota diversity and inflammation as a new target to improve mood: probiotic use in depressive disorder. Psychiatr Danub. 2023;35(Suppl 2):72-6. Top of Form Bottom of Form