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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

Contact Information


Dong-Mi Shin,

Probiotics, RCT, Gut microbiota, Cognitive function, Mood status, Healthy older adults


Probiotics have been proposed to ameliorate cognitive impairment and depressive disorder via the gut-brain axis in patients and experimental animal models. However, the beneficial role of probiotics in brain functions of healthy older adults remains unclear. Therefore, a randomized, double-blind, and placebo-controlled multicenter trial was conducted to determine the effects of probiotics on cognition and mood in community-dwelling older adults. Sixty-three healthy elders (≥65 years) consumed either placebo or probiotics containing Bifidobacterium bifidum BGN4 and Bifidobacterium longum BORI for 12 weeks. The gut microbiota was analyzed using 16S rRNA sequencing and bioinformatics. Brain functions were measured using the Consortium to Establish a Registry for Alzheimer's disease, Satisfaction with life scale, stress questionnaire, Geriatric depression scale, and Positive affect and negative affect schedule. Blood brain-derived neurotrophic factor (BDNF) was determined using enzyme-linked immunosorbent assay. Relative abundance of inflammation-causing gut bacteria was significantly reduced at Week 12 in the probiotics group (p < .05). The probiotics group showed greater improvement in mental flexibility test and stress score than the placebo group (p < .05). Contrary to placebo, probiotics significantly increased serum BDNF level (p < .05). Notably, the gut microbes significantly shifted by probiotics (Eubacterium and Clostridiales) showed significant negative correlation with serum BDNF level only in the probiotics group (RS = -0.37, RS = -0.39, p < .05). In conclusion, probiotics promote mental flexibility and alleviate stress in healthy older adults, along with causing changes in gut microbiota. These results provide evidence supporting health-promoting properties of probiotics as a part of healthy diet in the older adults.


Kim, C.S., Cha, L., Sim, M., Jung, S., Chun, W. Y., Baik, H. W., & Shin, D.-M. (2020). 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. The Journals of Gerontology: Series A, 76(1), 32–40.





Conent Area

Chong-Su Kim

EWB-Related Construct

(3) positive affect, (4) QoL

Study Design

Species or Study Population

(5) RCT

Sex (%Female)


Age (Mean, SD)

71.55 (4.30)

Younger Controls?


Longitudinal Data?


Sample Size



12-week probiotic intervention

Ethnicity (%white)


Inclusion Criteria

(1) Subjects had to be over 65 years old
(2) Subjects had to consent to be randomly assigned and refrain from consuming any other dietary supplements.

Exclusion Criteria

(1) participants with the use of antibiotics, anti-inflammatory medications, and gastrointestinal medicine within the past 3 months;
(2) participants with regular intake of probiotics within the past 3 months;
(3) Participants who are incapable of living independently.

EWB Measures

Satisfaction With Life Scale (SWLS)
positive and Negative affect (The Positive Affect and Negative Affect Schedule (PANAS))

Non-EWB Behavioral

The Korean version of the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD-K)
the Perceived Stress Inventory-korean (PSI-K): None Perceived Stress Inventory
The Korean version of Geriatric Depression Scale (GDS-K): None Geriatric Depression Scale

Physiological Measures


Brain IMaging Modality

Brain IMaging Paradigm


Brain Region/Circuit


Biological Measures


Other Neural Measures

Data Availability?


Data Avalability Details


Diagnostic Measures

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