Table 6.
Probiotic influence on cognition in healthy individuals.
| References | Pop.a | Study design | Probiotic manipulation | Duration | Cognitive measures and results |
|---|---|---|---|---|---|
| Allen et al. (99) | 22 healthy adults, 25.5 ± 1.2 years | DB, RM | B. longum 1714 strain vs. placebo | 4 weeks | Learning: Probiotic improved Sustained attention: No differences Emotion recognition: No differences Emotional Stroop: No differences |
| Benton et al. (100) | 126 healthy adults, 48–79 61.8 ± 7.3 years | DB, RCT | 65 mL L. casei*-containing (6.5 x 109 CFU) vs. placebo milk | 20 days | Short-term memory: Probiotic impaired after 20 (not 10) days Long-term memory: No differences Verbal fluency: No differences Intelligence: No differences |
| Chong et al. (101) | 111stressed adults, 18–60 years | DB, RCT | L. plantarum DR7(1 x 109 CFU) vs. placebo powder | 12 weeks | Social Emotion Cognition: Probiotic improved speed Verbal learning and memory: Probiotic improved speed Psychomotor performance: No differences Attention: No differences Visual learning and memory: No differences Associate learning: No differences Working memory: No differences Executive function: No differences |
| Chung et al. (102) | 36 healthy older adults, 60–75 65.0 ± 1.1 years | DB, RCT | L. helveticus IDCC3801 (500, 1,000, vs. 2,000 mg) vs. placebo capsules | 12 weeks | Sustained Attention: 1,000 mg probiotic improved Selective attention: 500 mg probiotic improved Working memory: No differences Short-term memory: No differences Long-term memory: No differences |
| Kelly et al. (97) | 29 healthy adults, 20–33 24.6 ± 0.8 years | DB, RCT, Cross-over | L. rhamnosus JB-1 (1 x 109 CFU) vs. placebo capsules | 4 weeks | Memory: No differences Attention switching: No differences Sustained Attention: No differences Emotional interference: No differences Emotion recognition: No differences |
| Lew et al. (98) | 103 stressed adults, 18–60 years | DB, RCT | L. plantarum P8 (2 x 1010 CFU) vs. placebo sachets | 12 weeks | Social emotional cognition: Probiotic improved speed Memory: Probiotic improved Target detection and identification: No differences |
| Papalini et al. (103) | 58 healthy adults, 18–40 years | DB, RCT | Multispeciesb probiotic (5 x 109 CFU) vs. placebo powder | 4 weeks | Emotional reactivity: No differences Emotional interference: No differences Selective attention: No differences Pre vs. post stress working memory: Probiotic improved |
CFU, colony forming units; DB, double blind; RM, repeated; M, measures; RCT, randomized controlled trial.
*
Strain not reported.
a
Mean ± SD and/or range
b
B. bifidum W23, B. lactis W51, B. lactis W52, L. acidophilus W37, L. brevis W63, L. casei W56, L. salivarius W24, L. lactis W19, and L. lactis W58.
B, Bifidobacterium; L, Lactobacillus.