Bifidobacterium breve MAK40B22B and Improved Cognitive Function

Research synthesisModerate evidenceMixed effect size3 studies · 3 beneficial · 0 neutral · 0 harmful

Across all 3 studies (all randomized controlled trials), Bifidobacterium breve MAK40B22B showed small to large beneficial effects on cognitive function in older adults with mild cognitive impairment or memory complaints. All 3 studies reported statistically significant improvements, primarily on subscales of memory and global cognition. Effects were typically observed at 16-24 weeks, and all studies used the A1 strain (MAK40B22B), though no specific dose range was consistently reported.

Studied populations: Older adults with mild cognitive impairment or memory complaints (ages 65-88)

Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Available evidence is overwhelmingly positive — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Effect sizes varied from small to large, and benefit was observed only on specific cognitive subscales, not across all measures — the clinical significance of these subscale improvements is unclear.

Generated May 12, 2026

4 of 4 papersPopulation:

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
- 2022-06-28
- RCT · n = 130
- Journal of Alzheimer's Disease 88(1)
- - D. Asaoka
  - Jinzhong Xiao
  - T. Takeda
  - N. Yanagisawa
  - Takahiro Yamazaki
  - Yoichiro Matsubara
  - Hideki Sugiyama
  - Noemi Endo
  - Motoyuki Higa
  - K. Kasanuki
  - Y. Ichimiya
  - S. Koido
  - Kazuya Ohno
  - François Bernier
  - N. Katsumata
  - A. Nagahara
  - H. Arai
  - T. Ohkusa
  - Nobuhiro Sato
- PubMed: 35570493
- DOI: 10.3233/jad-220148
4 Insights on
- Improved Cognitive Function
- High evidence
- Rigorous Journal
Improvement of cognitive function was observed on some subscales scores only likely due to the lower sensitiveness of these tests for MCI subjects.
Effect
Beneficial
Effect size
Small
Significant
Yes
Probiotic Bifidobacterium breve in Improving Cognitive Functions of Older Adults with Suspected Mild Cognitive Impairment: A Randomized, Double-Blind, Placebo-Controlled Trial
- 2020-09-01
- RCT · n = 80
- Journal of Alzheimer's Disease 77(1)
- - Jinzhong Xiao
  - N. Katsumata
  - F. Bernier
  - Kazuya Ohno
  - Yuki Yamauchi
  - T. Odamaki
  - K. Yoshikawa
  - Kumie Ito
  - Toshiyuki Kaneko
- PubMed: 32623402
- DOI: 10.3233/JAD-200488
7 Insights on
- Improved Cognitive Function
- High evidence
- Highly Cited
- Rigorous Journal
RBANS total score was significantly improved in probiotic group compared with placebo... after 16 weeks of consumption, in particular with significant improvement in domain scores of immediate memory, visuospatial/constructional, and delayed memory (p < 0.0001)
Effect
Beneficial
Effect size
Large
Significant
Yes
Effects of Bifidobacterium breve A1 on the cognitive function of older adults with memory complaints: a randomised, double-blind, placebo-controlled trial.
- 2019-05-28
- RCT · n = 121
- Beneficial Microbes 10(5)
- - Y. Kobayashi
  - T. Kuhara
  - M. Oki
  - J.‐Z. Xiao
- PubMed: 31090457
- DOI: 10.3920/BM2018.0170
9 Insights on
- Improved Cognitive Function
- High evidence
- Highly Cited
- Clinical
the subscale 'immediate memory' of RBANS and MMSE total score in the subjects with low RBANS total score at baseline.
Effect
Beneficial
Effect size
Small
Significant
Yes
Administration of Bifidobacterium breve Improves the Brain Function of Aβ1-42-Treated Mice via the Modulation of the Gut Microbiome
- 2021-05-11
- Clinical Trial
- Nutrients 13(5)
- - G. Zhu
  - Jianxin Zhao
  - Hao Zhang
  - Wei Chen
  - Gang Wang
- PubMed: 34064762
- DOI: 10.3390/nu13051602
11 Insights on
- Improved Cognitive Function
- Low evidence
- Animal Study
Overall, these findings reveal that *B. breve* CCFM1025 and WX have beneficial effects on cognition via the modulation of the gut microbiome, and thus represent a novel probiotic dietary intervention for delaying the progression of AD.
Effect
Beneficial
Effect size
Large

Bifidobacterium breve MAK40B22B and Improved Cognitive Function

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

Probiotic Bifidobacterium breve in Improving Cognitive Functions of Older Adults with Suspected Mild Cognitive Impairment: A Randomized, Double-Blind, Placebo-Controlled Trial

Effects of Bifidobacterium breve A1 on the cognitive function of older adults with memory complaints: a randomised, double-blind, placebo-controlled trial.

Administration of Bifidobacterium breve Improves the Brain Function of Aβ1-42-Treated Mice via the Modulation of the Gut Microbiome