Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Feb 15;12(4):4010-4039.
doi: 10.18632/aging.102810. Epub 2020 Feb 15.

Efficacy of Probiotics on Cognition, and Biomarkers of Inflammation and Oxidative Stress in Adults With Alzheimer's Disease or Mild Cognitive Impairment - A Meta-Analysis of Randomized Controlled Trials

Affiliations
Free PMC article

Efficacy of Probiotics on Cognition, and Biomarkers of Inflammation and Oxidative Stress in Adults With Alzheimer's Disease or Mild Cognitive Impairment - A Meta-Analysis of Randomized Controlled Trials

Haoyue Den et al. Aging (Albany NY). .
Free PMC article

Abstract

Probiotics are live microbes that confer health benefits to the host. Preliminary animal evidence supports the potential role of probiotics in ameliorating cognitive health, however, findings from clinical trials in Alzheimer's disease (AD) or mild cognitive impairment (MCI) subjects are controversial. Thus, a meta-analysis is needed to clarify the efficacy of probiotics on cognition in AD or MCI patients. EMBASE, PubMed, Web of Science and Cochrane library were systematically searched and manually screened for relevant published randomized controlled trials (RCTs). Among the 890 citations identified, 5 studies involving 297 subjects met eligibility. There was a significant improvement in cognition (SMD = 0.37; 95% CI, 0.14, 0.61; P = 0.002; I2 = 24%), while a significant reduction in malondialdehyde (SMD = -0.60; 95% CI, -0.91, -0.28; P = 0.000; I2 = 0.0%) and high-sensitivity C-reactive protein (SMD = -0.57; 95% CI, -0.95, -0.20; P = 0.003; I2 = 0.0%) post-intervention levels between the probiotics and control group. This meta-analysis indicated that probiotics improved cognitive performance in AD or MCI patients, possibly through decreasing levels of inflammatory and oxidative biomarkers. However, current evidence is insufficient, and more reliable evidence from large-scale, long-period, RCT is needed.

Keywords: Alzheimer’s disease; cognition; meta-analysis; mild cognitive impairment; probiotics.

Conflict of interest statement

CONFLICTS OF INTEREST: The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
PRISMA flow diagram of the literature search and abstraction process.
Figure 2
Figure 2
Summary of risk of bias assessment: judgments of the review authors on each risk of bias item for the included studies (n = 5). One study was rated as “low risk of bias”, and the other four were assessed as “moderate risk of bias.” No study was judged as “high risk of bias”.
Figure 3
Figure 3
Forest plot showing the standardized mean difference (SMD) in cognitive enhancement, comparing the probiotics group versus the control group. Weights were assigned according to the number of subjects and SD using STATA 12. A fixed-effects model was applied to the meta-analysis. The sizes of the data markers represent the weight of each study, and the diamond indicates the overall estimated effect.
Figure 4
Figure 4
Forest plot showing the effects in the probiotics group versus the control group on biomarkers of inflammation and oxidative stress. (A) Meta-analysis of the effects of probiotics on total anti-oxidant capacity (TAC). (B) Meta-analysis of the effects of probiotics on total glutathione (GSH). (C) Meta-analysis of the effects of probiotics on malondialdehyde (MDA). (D) Meta-analysis of the effects of probiotics on nitric oxide (NO). (E) Meta-analysis of the effects of probiotics on high-sensitivity C-reactive protein (hs-CRP). Weights were assigned according to the number of subjects and SD using STATA 12. A random-effects model was applied to the meta-analysis of TAC, while other biomarkers used a fixed-effects model. The sizes of data markers represent the weight of each study, and the diamonds indicate the overall estimated effect. SMD, standardized mean difference.

Similar articles

See all similar articles

References

    1. ADI. World Alzheimer Report 2018: The state of the art of dementia research: New frontiers. An Analysis of Prevalence, Incidence, Cost and Trends. London: Alzheimer's Disease International; 2018.
    1. Deng H, Mi MT. Resveratrol Attenuates Aβ25-35 Caused Neurotoxicity by Inducing Autophagy Through the TyrRS-PARP1-SIRT1 Signaling Pathway. Neurochem Res. 2016; 41:2367–79. 10.1007/s11064-016-1950-9 - DOI - PubMed
    1. Gauthier S, Reisberg B, Zaudig M, Petersen RC, Ritchie K, Broich K, Belleville S, Brodaty H, Bennett D, Chertkow H, Cummings JL, de Leon M, Feldman H, et al. , and International Psychogeriatric Association Expert Conference on mild cognitive impairment. Mild cognitive impairment. Lancet. 2006; 367:1262–70. 10.1016/S0140-6736(06)68542-5 - DOI - PubMed
    1. ADI. World Alzheimer Report 2019: Attitudes to dementia. London: Alzheimer's Disease International; 2019.
    1. Manayi A, Saeidnia S, Gohari AR, Abdollahi M. Methods for the discovery of new anti-aging products—targeted approaches. Expert Opin Drug Discov. 2014; 9:383–405. 10.1517/17460441.2014.885014 - DOI - PubMed
Feedback