Table 2.
The effects of probiotic/prebiotic/symbiotic supplementation on cognitive functions in healthy subjects.
| Study | Design | Mean Follow-Up | Country | Sample Size | Average Age (Year) | Sex Male/Female (%) |
Intervention | Main Results |
|---|---|---|---|---|---|---|---|---|
| Kim CS et al. [18] | RCT | 12 weeks | Republic of Korea | 63 | 71.5 ± 4.3 | 49.06/50.94 | The research participants were administered a probiotic supplement consisting of a total of 1 × 109 CFU of Bifidobacterium bifidum BGN4 and Bifidobacterium longum BORI, suspended in soybean oil. | At week 12, individuals in the probiotics group demonstrated a notable enhancement in mental flexibility compared to those in the placebo group (p < 0.05). Enhanced cognitive and mental capabilities following the administration of probiotic supplements. |
| Shi S et al. [19] | RCT | 8 weeks | China | 60 | 64.1 ± 3.4 | 57/43 | Participants were required to consume one sachet of probiotics (BB68S, 5 × 1010 CFU per sachet) or a placebo daily. | BB68S demonstrated a significant enhancement in participants’ cognitive functions, as evidenced by a notable 18.89-point increase in the total RBANS score post-intervention (p < 0.0001). This improvement was particularly prominent in the domains of immediate memory, visuospatial/constructional abilities, attention, and delayed memory. |
| Sakurai K et al. [20] | RCT | 12 weeks | Japan | 78 | 76.8 ± 4.6 | 46/54 | The participants received a 1 g packet containing Lactiplantibacillus plantarum OLL2712 cells in a quantity exceeding 5 × 109 daily. | The analysis results indicated that the intake of OLL2712 exerted a protective effect on memory function in the elderly (p < 0.05). |
| Czajeczny D et al. [21] | RCT | 6 weeks | Poland | 38 | 19–31 | 100% female | The individuals received a probiotic supplement containing Bifidobacterium lactis BS01 and Lactobacillus acidophilus LA02. | In the group supplemented with probiotics, there was a significant improvement in cognitive performance compared to the placebo group, as assessed by the Wisconsin Card Sorting Test (WCST) (p < 0.05). |
| M Ni [22] | RCT | 12 weeks | United Kingdom | 72 | >60 | 37/63 | The elderly subjects received a daily intake of one sachet of prebiotic dietary supplement. | In comparison to the placebo group, the prebiotic intervention arm exhibited an enhanced cognition factor score (0.482; 95% CI 0.823–0.141; p = 0.014). |
| Azuma N et al. [23] | RCT | 12 weeks | Japan | 80 | 64.6 ± 7.1 | 50/50 | During the 12-week study period, participants ingested test drinks containing 1 × 1010 CFU of GCL2505 per 100 g along with 2.0 g of inulin per 100 g. | Substantial enhancements were observed in the scores within the neurocognitive index domain (p = 0.027), evaluating overall cognitive function, as well as across the attention, cognitive flexibility, and executive function domains (p = 0.044). |
| Berding K et al. [24] | RCT | 4 weeks | Ireland | 18 | 26 ± 1.3 | 100% female | The female participants received 12.5 g of Litesse® Ultra (>90% polydextrose (PDX) polymer). | PDX demonstrated enhanced cognitive flexibility, indicated by a reduction in errors during the Intra–Extra Dimensional Set Shift (IED) task. Improved sustained attention was evident through a higher number of correct responses and rejections in the Rapid Visual Information Processing (RVP) task. |
| Sanborn V et al. [25] | RCT | 3 months | USA | 145 | 64.3 ± 5.5 | 40.7/59.3 | The intervention involved Culturelle Vegetarian Capsules which contained a blend of 10 billion CFUs of Lactobacillus rhamnosus GG for the experimental group. | Probiotic supplementation with Lactobacillus rhamnosus GG was linked to enhanced cognitive performance in middle-aged and older adults (p < 0.05). |
| Louzada ER et al. [26] | RCT | 6 months | Brazil | 49 | 77.2 ± 1.3 | 80/20 | The synbiotic group was administered two daily doses (6 g + 6 g) of a compound containing fructooligosaccharide (6 g), L. paracasei (109 CFU), L. rhamnosus (109 CFU), L. acidophilus (109 CFU), and B. lactis (109 CFU). | According to their results, the supplement exhibits modest effects on reducing depressive symptoms and more favorable effects on cognitive functions in elderly individuals (MMSE; p < 0.05). |
| Sanborn V et al. [27] | RCT | 8 weeks | USA | 127 | 64.3 ± 3.6 | 42/58 | The probiotic supplement for the subjects was Lactobacillus rhamnosus GG (2 × 1010 CFU/day). | The probiotic intervention did not influence cognitive performance. |
| Edebol Carlman HMT et al. [28] | RCT | 8 weeks | Sweden | 22 | 24.2 ± 3.4 | 27/73 | The subjects received a combination of three probiotic strains—Lactobacillus helveticus R0052 (CNCM-I-1722; 2 × 109 CFU), Lactiplantibacillus plantarum R1012 (CNCM-I-3736; 8 × 108 CFU), and Bifidobacterium longum R0175 (CNCM-I-3470; 7 × 107 CFU)—at a dosage of 3 g per day. | The probiotic intervention did not influence cognitive performance. |
| Ascone et al. [29] | RCT | 4 weeks | Germany | 59 | 27.1 ± 6.7 | 43/57 | The participants received a multi-strain probiotic (Vivomixx®) at a daily dosage of 4.4 g. | The administered multi-strain probiotic did not induce any effects on cognition or mental well-being in young, healthy adults. |
| Cannavale CN et al. [30] | RCT | 4 weeks | USA | 26 | 25–45 | 58/42 | Participants underwent testing before and after a 4-week consumption period, which included 8 oz of a dairy-based fermented beverage containing 25–30 billion CFUs of live and active kefir cultures. | The fermented dairy beverage led to enhanced performance in two aspects of relational memory: misplacement (p = 0.04) and object-location binding (p = 0.03). |
BB68S: Bifidobacterium longum BB68S; CFU: colony-forming unit; IED: Intra–Extra Dimensional; PDX: polydextrose; RCT: randomized controlled trial; RBANS: Repeatable Battery for the Assessment of Neuropsychological Status; RVP: Rapid Visual Information Processing; WCST: Wisconsin Card Sorting Test.