We previously reported the therapeutic potential of Bifidobacterium breve A1 (B. breve A1) for preventing cognitive impairment in Alzheimer’s disease model mice, which suggested that supplementation of the probiotics could be an effective therapeutic strategy for managing cognitive function in mild cognitive impairment (MCI).

We conducted an open-label, single-arm study to examine the effects of 24-week supplementation of B. breve A1 on elderly with MCI in Aki Orthopedics Rehabilitation Clinic in Japan.

27 participants were screened by their Mini Mental State Examination (MMSE) scores.

Cognitive function was assessed using MMSE and Digit Symbol Substitution Test (DSST) at baseline and every 8 weeks. Mental condition and quality of life for gastrointestinal symptoms were measured using the Profile of Mood States 2nd Edition (POMS2), and the Gastrointestinal Symptom Rating Scale (GSRS).

Of the 27 participants enrolled, 19 completed the study. MMSE scores were significantly increased during the intervention by mixed model Dunnett’s test and Wilcoxon signed-rank tests (+1.7, P < 0.01). POMS2 and GSRS scores were significantly improved during intervention when analyzed by Wilcoxon signed-rank tests.

The present study showed that oral supplementation of B. breve A1 in participants with MCI improved cognitive function, thus suggesting the potential of B. breve A1 for improving cognitive function and maintaining quality of life of the elderly. Further randomized, double-blind placebo-controlled studies are worth conducting to examine the beneficial effect of B. breve A1.