Table 1.
Characteristics of the studies included in the systematic review.
| Study | Intervention Type | Delivery Method | Active Compound | Dose | Frequency (dose/day) | Duration (days) | Active/Control | Mean Age (SE) | Sex (M/F) | Anxiety Measure* | Effect | Stress Measure* | Effect2 | Participants |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Andersson et al.35 | probiotic | capsule | Lactobacillus plantarum 299v | 10 x 109 CFU | 1 | 21 | 21/20 | range 18-30 | 13/28 | - | - | salivary cortisol | ↓ | students e.s. |
| salivary immunoglobulin A | ns | |||||||||||||
| Culpepper et al.5 | probiotic | capsule | Lactobacillus helveticus R0052 | 3 × 109 CFU | 1 | 42 | 145 | 19.9 (0.1) | 209/372 | - | - | self-reported stress | ↓ for B. Bifidum only, only in sleep deprived students | students e.s. |
| Bifidobacterium longum ssp. infantis R0033 | 147 | |||||||||||||
| Bifidobacterium bifidum R0071 | 142 | |||||||||||||
| placebo | 147 | |||||||||||||
| Hughes et al. (2011) | prebiotic | sachet | galactooligosaccharide | 0, 2.5, 5 g | 1 | 56 | 279/140 | 19.9 (0.1) | 207/212 | - | - | self-reported stress | ns | students e.s. |
| Karbownik et al.34 | probiotic | capsule | Saccharomyces boulardii | 5 x 109 CFU | 1 | 30 | 31/29 | 22.6 | 37/55 | STAI state | ns | salivary cortisol | ns | students e.s. |
| salivary metanephrine | ns | |||||||||||||
| pulse rate | ↑ | |||||||||||||
| Kato-Kataoka et al.28 | probiotic | liquid | Lactobacillus casei Shirota | 100 x 109 CFU | 1 | 56 | 23/24 | 22.8 (0.4) | 25/22 | STAI state | ns | visual analogue stress scale | ↓ | students e.s. |
| salivary cortisol | ↓ | |||||||||||||
| salivary alpha-amylase | ns | |||||||||||||
| Kato-Kataoka et al.29 | probiotic | liquid | Lactobacillus casei Shirota | 100 x 109 CFU | 1 | 56 | 24/23 | 22.9 (0.4) | 26/21 | STAI state | ns | salivary cortisol | ns | students e.s. |
| HADS | - | salivary immunoglobulin A | ns | |||||||||||
| Kitaoka et al.39 | prebiotic | capsule | Fermented Ginseng | 205 mg | 9 | 8 | 8/8 | 20.7 (0.4) | 16/0 | STAI total | - | salivary cortisol | ns | healthy subjects |
| POMS | ns | salivary immunoglobulin A | ns | |||||||||||
| urinary 8-hydroxydeoxyguanosine | ns | |||||||||||||
| Kiecolt-Glaser et al.38 | prebiotic | capsule | omega-3 polyunsaturated fatty acid | 2.5 g | 1 | 84 | 34/34 | 23.7 (1.9) | 38/30 | BAI | ↓ | - | - | students e.s. |
| Liu et al. (2019) | probiotic | capsule | Lactobacillus plantarum PS128 | 30 x 109 CFU | ns | 30 | 36/35 | 10.0 | 71/0 | CBCL | ns | - | - | ASD children |
| Manos et al.36 | prebiotic | capsule | omega-3-PUFA | 782 mg | 4 | 84 | 10/8 | 14.7 | 0/18 | BAIT | ↑ | - | - | anorexic girls |
| Marcos et al.33 | probiotic | liquid | Lactobacillus delbrueckii bulgaricus | 1 x 109 CFU | 2 | 21 | 73/63 | 18-23 | 40/96 | STAI state | ns | serum cortisol | ns | students e.s. |
| Streptococcus salivarius thermophilus | 10 x 109 CFU | STAI trait | ns | |||||||||||
| Lactobacillus casei DN114001 | 10 x 109 CFU | |||||||||||||
| Moller et al. (2017) | probiotic | capsule | Bifidobacterium breve | 112.5 x 109 CFU (total) | 1 | 14 | 57/48 | 20.2 | 36/69 | - | - | PASAT | ns | healthy subjects, stress task |
| B.longum | Blood pressure | ns | ||||||||||||
| B. infantis | ||||||||||||||
| Lactobacillus acidophilus | ||||||||||||||
| L. plantarum | ||||||||||||||
| L. paracasei | ||||||||||||||
| L. bulgaricus | ||||||||||||||
| Streptococcus thermophilus | ||||||||||||||
| Schmidt et al. (2014) | prebiotic | powder | fructooligosaccharides (FOS) | 5.5 g | 1 | 21 | 15 | 23.7 | 22/23 | STAI state | ns | PSS-10 | ns | healthy subjects |
| galactooligosaccharide (B-GOS) | 15 | Attentional dot-probe | ↓GOS only, unmasked | salivary cortisol | ↓ GOS only | |||||||||
| placebo | 15 | Facial expression recognition | ns | |||||||||||
| Emotional word recognition and recall | ns | |||||||||||||
| Tran et al.30 | probiotic | - | 18 species | 50 x 109 CFU | 1 | 28 | 14 | 20.6 | 20/66 | BAI | ns BAI total ↑ BAI-Panic, 50 x 10^9 CFU only | - | - | healthy students |
| 10 species | 50 x 109 CFU | 13 | ACQ-R | - | ||||||||||
| 18 species | 15 x 109 CFU | 15 | PSWQ | ↓50 x 10^9 CFU only | ||||||||||
| 10 species | 10 x 109 CFU | 15 | ||||||||||||
| placebo | 11 |
↓: improvement vs placebo; ↑: deminishment vs placebo; *: effect size estimated or calculated from reported data; ns: no significant effect; -: not reported or not applicable; ACQ-R: Anxiety control questionnaire-revised; BAI: Beck Anxiety Inventory; CBCL: Child Behaviour Checklist (Anxiety); CFU: colony forming units; HADS: Hospital Anxiety and Depression Scale; PASAT: Paced Auditory Serial Addition Test; PSS: Percieved Stress Scale-10; PSWQ: Penn state worry questionnaire; STAI: State-Trait Anxiety Inventory; e.s.: under examination stress.
* all the time point 2 are referred to POST-TREATMENT measurement