The Effect of Probiotics on Select Cognitive Domains in Mild Cognitive Impairment and Alzheimer's Disease: A Systematic Review and Meta-analysis

Overview

Journal J Alzheimers Dis Rep

Publisher IOS Press

Date 2025 Mar 4

PMID 40034358

Authors

Shashank Tripathi

Meenakshi Kaushik

Rekha Dwivedi

Prabhakar Tiwari

Manjari Tripathi

Rima Dada

Affiliations

Soon will be listed here.

Abstract

Background: Mild cognitive impairment (MCI) and Alzheimer's disease (AD) are progressive neurodegenerative disorders, and probiotics may offer therapeutic benefits by modulating gut microbiota and reducing inflammation.

Objective: This study systematically evaluated the impact of probiotics on cognitive function in MCI and AD through a meta-analysis of randomized controlled trials (RCTs).

Methods: A systematic review and meta-analysis were performed following PRISMA 2020 guidelines. PubMed, Embase, EBSCO, and Cochrane databases were searched for RCTs (January 2000-January 2024) on probiotic interventions lasting 8-24 weeks. Cognitive outcomes included Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), language, naming, visual-spatial, memory, and attention. Data were analyzed using R with a random-effects model to calculate pooled standardized mean differences (SMDs) with 95% confidence intervals (CIs). Risk of bias was rigorously assessed.

Results: Out of 2000 articles, 500 full texts were screened, and 10 studies were included. The meta-analysis showed varied effect sizes: MMSE (SMD: 0.28, 95%CI -0.35-0.91, p = 0.38), MoCA (SMD: 0.51, 95%CI -0.49-1.52, p = 0.33), language (SMD: -0.12, 95% CI -0.54-0.29, p = 0.56), naming (SMD: 0.02, 95%CI -0.69-0.74, p = 0.95), visual-spatial (SMD: 0.38, 95%CI -0.13-0.88, p = 0.14), memory (SMD: 0.20, 95%CI -0.15-0.55, p = 0.26), and attention (SMD: -0.07, 95%CI -0.44-0.30, p = 0.71). Positive SMDs suggest cognitive improvement, while non-significant negative SMDs indicate trends toward decline, inclined by probiotic strains, duration, and participant characteristics.

Conclusions: Probiotics did not significantly improve cognitive function in MCI and AD patients, with variability in effects across cognitive domains, suggesting the need for tailored interventions and future studies.

References

Liu C, Guo X, Chang X . Intestinal Flora Balance Therapy Based on Probiotic Support Improves Cognitive Function and Symptoms in Patients with Alzheimer's Disease: A Systematic Review and Meta-analysis. Biomed Res Int. 2022; 2022:4806163. PMC: 9398783. DOI: 10.1155/2022/4806163. View

Li X, Lv C, Song J, Li J . Effect of Probiotic Supplementation on Cognitive Function and Metabolic Status in Mild Cognitive Impairment and Alzheimer's Disease: A Meta-Analysis. Front Nutr. 2021; 8:757673. PMC: 8692377. DOI: 10.3389/fnut.2021.757673. View

Kruger J, Hillesheim E, Pereira A, Camargo C, Rabito E . Probiotics for dementia: a systematic review and meta-analysis of randomized controlled trials. Nutr Rev. 2020; 79(2):160-170. DOI: 10.1093/nutrit/nuaa037. View

Andrews V, Zammit G, OLeary F . Dietary pattern, food, and nutritional supplement effects on cognitive outcomes in mild cognitive impairment: a systematic review of previous reviews. Nutr Rev. 2023; 81(11):1462-1489. PMC: 10563860. DOI: 10.1093/nutrit/nuad013. View

Claus C, Staekenborg S, Verweij K, Schuur J, van der Werf S, Scheltens P . The clock drawing test is an important contribution to the Mini Mental State Examination in screening for cognitive impairment. Int J Geriatr Psychiatry. 2023; 38(4):e5914. DOI: 10.1002/gps.5914. View

Xiao J, Katsumata N, Bernier F, Ohno K, Yamauchi Y, Odamaki T . Probiotic Bifidobacterium breve in Improving Cognitive Functions of Older Adults with Suspected Mild Cognitive Impairment: A Randomized, Double-Blind, Placebo-Controlled Trial. J Alzheimers Dis. 2020; 77(1):139-147. PMC: 7592675. DOI: 10.3233/JAD-200488. View

Solanki R, Karande A, Ranganathan P . Emerging role of gut microbiota dysbiosis in neuroinflammation and neurodegeneration. Front Neurol. 2023; 14:1149618. PMC: 10225576. DOI: 10.3389/fneur.2023.1149618. View

Asaoka D, Xiao J, Takeda T, Yanagisawa N, Yamazaki T, Matsubara Y . Effect of Probiotic Bifidobacterium breve in Improving Cognitive Function and Preventing Brain Atrophy in Older Patients with Suspected Mild Cognitive Impairment: Results of a 24-Week Randomized, Double-Blind, Placebo-Controlled Trial. J Alzheimers Dis. 2022; 88(1):75-95. PMC: 9277669. DOI: 10.3233/JAD-220148. View

Pal A, Biswas A, Pandit A, Roy A, Guin D, Gangopadhyay G . Study of visuospatial skill in patients with dementia. Ann Indian Acad Neurol. 2016; 19(1):83-8. PMC: 4782559. DOI: 10.4103/0972-2327.168636. View

10.

Tiwari S, Atluri V, Kaushik A, Yndart A, Nair M . Alzheimer's disease: pathogenesis, diagnostics, and therapeutics. Int J Nanomedicine. 2019; 14:5541-5554. PMC: 6650620. DOI: 10.2147/IJN.S200490. View

11.

Fei Y, Wang R, Lu J, Peng S, Yang S, Wang Y . Probiotic intervention benefits multiple neural behaviors in older adults with mild cognitive impairment. Geriatr Nurs. 2023; 51:167-175. DOI: 10.1016/j.gerinurse.2023.03.006. View

12.

Talwar P, Sinha J, Grover S, Rawat C, Kushwaha S, Agarwal R . Dissecting Complex and Multifactorial Nature of Alzheimer's Disease Pathogenesis: a Clinical, Genomic, and Systems Biology Perspective. Mol Neurobiol. 2015; 53(7):4833-64. DOI: 10.1007/s12035-015-9390-0. View

13.

Jahn H . Memory loss in Alzheimer's disease. Dialogues Clin Neurosci. 2014; 15(4):445-54. PMC: 3898682. View

14.

Agahi A, Hamidi G, Daneshvar R, Hamdieh M, Soheili M, Alinaghipour A . Does Severity of Alzheimer's Disease Contribute to Its Responsiveness to Modifying Gut Microbiota? A Double Blind Clinical Trial. Front Neurol. 2018; 9:662. PMC: 6104449. DOI: 10.3389/fneur.2018.00662. View

15.

Thal L, Ferris S, Kirby L, Block G, Lines C, Yuen E . A randomized, double-blind, study of rofecoxib in patients with mild cognitive impairment. Neuropsychopharmacology. 2005; 30(6):1204-15. DOI: 10.1038/sj.npp.1300690. View

16.

Hwang Y, Park S, Paik J, Chae S, Kim D, Jeong D . Efficacy and Safety of C29-Fermented Soybean (DW2009) in Individuals with Mild Cognitive Impairment: A 12-Week, Multi-Center, Randomized, Double-Blind, Placebo-Controlled Clinical Trial. Nutrients. 2019; 11(2). PMC: 6412773. DOI: 10.3390/nu11020305. View

17.

Xiang S, Ji J, Li S, Cao X, Xu W, Tan L . Efficacy and Safety of Probiotics for the Treatment of Alzheimer's Disease, Mild Cognitive Impairment, and Parkinson's Disease: A Systematic Review and Meta-Analysis. Front Aging Neurosci. 2022; 14:730036. PMC: 8851038. DOI: 10.3389/fnagi.2022.730036. View

18.

Larroya-Garcia A, Navas-Carrillo D, Orenes-Pinero E . Impact of gut microbiota on neurological diseases: Diet composition and novel treatments. Crit Rev Food Sci Nutr. 2018; 59(19):3102-3116. DOI: 10.1080/10408398.2018.1484340. View

19.

Kim C, Cha L, Sim M, Jung S, Chun W, Baik H . Probiotic Supplementation Improves Cognitive Function and Mood with Changes in Gut Microbiota in Community-Dwelling Older Adults: A Randomized, Double-Blind, Placebo-Controlled, Multicenter Trial. J Gerontol A Biol Sci Med Sci. 2020; 76(1):32-40. PMC: 7861012. DOI: 10.1093/gerona/glaa090. View

20.

Zhu G, Zhao J, Zhang H, Chen W, Wang G . Probiotics for Mild Cognitive Impairment and Alzheimer's Disease: A Systematic Review and Meta-Analysis. Foods. 2021; 10(7). PMC: 8303183. DOI: 10.3390/foods10071672. View