Table 1.
Baseline characteristics of included meta-analyses investigating the effects of probiotics and synbiotics on PCOS.
| References | Included studies in meta-analysis (n) | Type of included studies in metaanalysis | Total sample size (n) | Participants' characteristics | Type and dose of intervention | Duration of interventions (weeks) | Main outcomes significant | Risk of bias assessment | Reported side effects | AMSTAR score |
|---|---|---|---|---|---|---|---|---|---|---|
| Hadi et al. (22) | 8 | RCTs (blinding, paralel) | 540 | Women with PCOS (25–30 years) | Live bacteria as probiotics or synbiotics (not in combination with other drugs or supplements) Lactobacillus, Bifidobacterium (2 × 107-2 × 1010) Inulin (0.8–20 gr) Placebo(starch, MDX) | 8–12 weeks | ↓FBS ↓Insulin ↓HOMA I-R ↓CRP ↓Total testosterone | Yes | No | Critically low |
| Miao et al. (23) | 7 (6 in iran and 1 in china) | RCTs | 486 | Women with PCOS | Probiotics and synbiotics Lactobacillus, Bacillus, Bifidobacterium, metformin as a co-intervention | 8–12 weeks | ↓HOMA I-R ↓Insulin | Yes | No | High |
| Li et al. (24) | 17 (15 in iran and 2 in china) | RCTs | 1,049 | Women with PCOS | Probiotics, prebiotics, and synbiotics (intake separately or in combination with other drugs, compared with placebo) 1 × 107 to 1010 | 8–12 weeks | ↓FPG fasting insulin ↓HOMA I-R ↓TG ↓Total cholesterol ↓LDL ↓VLDL-C ↑QUICKI | Yes | No | High |
| Tabrizi et al. (25) | 11 | RCTs | 730 | Women with PCOS (24–30 years) | Probiotic and/or symbiotic capsule contained: Lactobacillus, Bifidobacterium 2 × 108 to 2 × 1010 | 8–12 weeks | ↓Weight ↓BMI ↓FPG ↓ Insulin ↓HOMA I-R ↓TG ↓VLDL-C ↓CRP ↓MDA ↓Hirsutism ↓Total testosterone levels ↑QUICKI ↑NO ↑TAC ↑GSH ↑ SHBG | Yes | No | High |
| Shamasbi et al. (26) | 13 | RCTs | 855 | Women with PCOS (15–49 years) | Probiotics, prebiotics, and synbiotics Lactobacillus, Bifidobacterium (powder or capsule different doses) comparison group included the placebo or maltodextrin group | 8–12 weeks | ↑ SHBG ↑NO ↓FAI ↓MDA | Yes | No | Low |
| Heshmati et al. (27) | 7 | RCTs | 471 (236 women with PCOS and 235 controls) | Women with PCOS (25–30 years) | Probiotics (or synbiotics) and the placebo groups 2 × 109/complex | 8–12 weeks | ↑QUICKI ↓TG level ↓Fasting insulin ↓HDL | Yes | No | Low |
| Cozzolino et al. (28) | 9 | RCTs (Eight studies were double-blinded, whilst one study was triple-blinde) | 587 | Women with PCOS | Probiotic/symbiotic (Control group women with PCOS without therapy with probiotics or synbiotics or placebo) Lactobacillus, Bifidobacterium 2 × 108 to 3 × 1010 | 8 Cozzolino 12 weeks | ↓FPG ↓FBI ↓HOMA I-R ↓BMI ↓Serum TG ↓Serum testosterone ↑hs-CRP ↑NO ↑TAC ↑GSH ↑MDA | Yes | No | High |
| Liao et al. (21) | 6 | RCTs | 406 | Women with PCOS aged 25–28.5 years | Probiotic supplementation | 8–12 weeks | ↑QUICKI ↓FBI ↓TG ↓VLDL-C | Yes | No | NA |
FBS, fasting blood sugar; CRP, C reactive protein; hsCRP, high sensitive C reactive protein; BMI, Body mass index; FPG, fasting plasma glucose; SHBG, sex hormone binding globulin; NO, nitric oxide; FBI, fasting blood insulin; TG, triglycerides; QUICKI, quantitative insulin sensitivity check index; TAC, total antioxidant capacity; GSH, total glutathione; MDA, malondialdehyde; FAI, Free Androgen Index; VLDL-C, very low density lipoprotein-cholesterol; HDL-C, high density lipoprotein-cholesterol; HOMA I-R, homeostatic model assessment-insulin resistance.