Table 2.
Characteristics of the included studies
| Studies | Country | Study design | Participant | Sample size and sex | Sample size | Trial duration (Week) | Means age | Means BMI | Intervention | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| IG | CG | IG | CG | IG | CG | Probiotic/synbiotic dose | Control group | ||||||
| Toejing et al. (2021) [2] | Thailand | paralell, R, PC, DB | T2DM | M/F (18, 18) | 18 | 18 | 12 | 63.5 ± 5.94 | 61.78 ± 7.73 | 23.22 ± 2.72 | 23.05 ± 2.6 | Probiotic (L. paracasei HII01) 50*10^9 CFU/ml | Placebo |
| Kanazawa et al. (2021) [26] | Japan | Paralell, R, C, | T2DM | M/F (65, 21) | 44 | 42 | 24 | 61.1 ± 11.0 | 55.9 ± 10.7 | 29.5 ± 4.4 | 29.1 ± 3.7 | Synbiotic mixture (10.5 g/day) | Placebo |
| Ismail et al. (2021) (A) [54] | Egypt | Paralell, R, PC, DB | T2DM | M/F | 50 | 25 | 16 | 48.3 ± 12.9 | 46.4 ± 13.2 | 31.1 ± 5.3 | 30.2 ± 6 | Probiotic (B. Animalis Dn-173 010) + Balance Diet | Yogurt |
| Ismail et al. (2021) (B) [54] | Egypt | Paralell, R, PC, DB | T2DM | M/F | 50 | 25 | 16 | 48.6 ± 11.5 | 46.4 ± 13.2 | 28.5 ± 7.6 | 30.2 ± 6 | Natural Baking Yeast (Saccharomyces Cerevisiae) + Balance Diet | Supplement |
| Tay et al. (2020) [3] | New Zealand | Paralell, R, PC, DB | Prediabetic | M/F (8, 18) | 15 | 11 | 12 | 52.9 ± 8.7 | 54.1 ± 6.4 | 34.7 ± 4.9 | 33.6 ± 3.7 | L. rhamnosus HNOO1 (6*109 CFU) | Placebo |
| Toshimitsu et al. (2020) [36] | Japan | Paralell, R, PC, DB | Prediabetic | M/F (86, 40) | 62 | 64 | 12 | 50.6 ± 6.9 | 51.2 ± 7.6 | 24.7 ± 3.3 | 24.9 ± 3.2 | L. plantarum OLI2712 (112 g (> 5*109/112 g yogurt) | Yogurt |
| Farrokhian et al. (2019) [48] | Iran | Paralell, R, PC, DB | T2DM/Diabetes/CHD | M/F (38, 22) | 30 | 30 | 12 | 64.2 ± 12 | 64 ± 11.7 | 32.3 ± 6 | 29.6 ± 4.6 | Synbiotic (3 bacteria) (probiotic (2*109 CFU/g/day each) + inulin) | Placebo |
| Mazruei Arani et al. (2019) [42] | Iran | Paralell, R, PC, DB | Diabetic nephropathy | M/F | 30 | 30 | 12 | 62.7 ± 9.1 | 60.3 ± 8.5 | 30.3 ± 5.6 | 31.1 ± 4.6 | Probiotic honey (2500 mg/day) | Honey |
| Soleimani et al. (2019) [25] | Iran | Paralell, R, PC, DB | T2DM/dialysis | M/F (42, 18) | 30 | 30 | 12 | 62.8 ± 12.7 | 62.8 ± 14.8 | 26.4 ± 5.4 | 26.9 ± 4.7 | Synbiotic (probiotic + inulin) | Placebo |
| Sabico et al. (2019) [21] | Saudi Arabia | Paralell, R, PC, DB | T2DM | M/F | 31 | 30 | 24 | 48 ± 8.3 | 46.6 ± 5.9 | 29.4 ± 5.2 | 30.1 ± 5.0 | Probiotic (2.5*109 CFU/ml) | Placebo |
| Raygan et al. (2018) [38] | Iran | Paralell, R, PC, DB | T2DM/ CHD | M/F | 30 | 30 | 12 | 60.7 ± 9.4 | 61.8 ± 9.8 | 30.3 ± 5.2 | 29.3 ± 4.1 | Probiotic (mixture) | Placebo |
| Kobyliak et al. (2018) [12] | Ukraine | Paralell, R, PC, DB | T2DM | M/F | 31 | 22 | 12 | 52.23 ± 1.74 | 57.18 ± 2.06 | 34.7 ± 1.29 | 35.65 ± 1.57 | Probiotic (multistrain) (10 g/day) | Placebo |
| Mafi et al. (2018) [44] | Iran | Paralell, R, PC, DB | Diabetic nephropathy | M/F | 30 | 30 | 12 | 58.9 ± 8.8 | 60.9 ± 4.4 | 25.3 ± 2.3 | 26.3 ± 3.2 | Probiotic (multistrain) (8*109 CFU/ml/) | Placebo |
| Hsieh et al. (2018) (A) [45] | Taiwan | Paralell, R, PC, DB | T2DM | M/F | 25 | 12 | 12 | NR | NR | NR | NR | Probiotic (L. ruteri. live) (2*109 CFU/capsule) | Placebo |
| Hsieh et al. (2018) (B) [45] | Taiwan | Paralell, R, PC, DB | T2DM | M/F | 25 | 12 | 12 | NR | NR | NR | NR | Probiotic (L. ruteri. Heat-killed) (1*1010 CFU/capsule) | Placebo |
| Miraghajani et al. (2017) [41] | Iran | Paralell, R, PC,SB | T2DM/CKD | M/F (18, 22) | 20 | 20 | 12 | 56.90 ± 1.81 | 53.60 ± 1.60 | 26.68 ± 0.71 | 26,58 ± 0.73 | Probiotic soy milk (200 ml/day) | Soy milk |
| Soleimani et al. (2017) [37] | Iran | Paralell, R, PC, DB | T2DM/dialysis | M/F (40, 20) | 30 | 30 | 12 | 54 ± 16 | 59.4 ± 16 | 25.5 ± 5.6 | 27 ± 6.4 | Probiotic (multistrain) (mixture) | Placebo |
| Firouzi et al. (2017) [46] | Malaysia | Paralell, R, PC, DB | T2DM | M/F (65, 71) | 68 | 68 | 12 | 52.9 ± 9.2 | 54.2 ± 8.3 | 29.2 ± 5.6 | 29.3 ± 5.3 | Probiotic (multistrain) (109 3 ach/twice a day) | Sachet |
| Mohseni et al. (2018) [39] | Iran | Paralell, R, PC, DB | T2DM/foot ulcer | M/F (40, 20) | 30 | 30 | 12 | 62.6 ± 9.7 | 58.5 ± 11 | 26.4 ± 3 | 25.3 ± 3.7 | Probiotic (multistrain) (2.*109 cfu/g each) | Placebo |
| Rezaei et al. (2017) [15] | Iran | Paralell, R, PC, DB | T2DM | M/F (44, 46) | 45 | 45 | 12 | 50.49 ± 10.92 | 50.13 ± 9.2 | 28.9 ± 3.5 | 29.5 ± 1.6 | Probiotic (multistrain) (300,000 (300 g/day)) | Yogurt |
| Sato et al. (2017) [20] | Japan | Paralell, R, PC, DB | T2DM | M/F (49, 19) | 34 | 34 | 12 | 64 ± 9.2 | 65 ± 8.3 | 24.2 ± 2.6 | 24.6 ± 2.6 | Probiotic (multistrain) (mixture) | Placebo |
| Feizollahzadeh et al. (2016) [47] | Iran | Paralell, R, PC, DB | T2DM | M/F (19, 21) | 20 | 20 | 12 | 56.9 ± 8.09 | 53.6 ± 7.15 | 26.68 ± 3.17 | 26.58 ± 3.26 | Probiotic soy milk (L. plantarum A7) (200 ml/day) | Conventional soy milk |
| Bayat et al. (2016) (A) [50] | Iran | Paralell, R, C | T2DM | M/F (12, 28) | 20 | 20 | 12 | 54.1 ± 9.54 | 46.95 ± 9.34 | 28.77 ± 4.59 | 29.75 ± 4.66 | Probiotic yogurt (150 g/day) | Dietary advice |
| Bayat et al. (2016) (B) [50] | Iran | Paralell, R, C | T2DM | M/F (18, 22) | 20 | 20 | 12 | 53.65 ± 6.99 | 51.8 ± 2.24 | 27.98 ± 4.2 | 28.95 ± 3.34 | Probiotic yogurt + pumpkin (150 gr + 100 gr) | Pumpkin |
| Mobini et al. (2017) (A), (B) [53] | Sweden | Paralell, R, PC, DB | T2DM | M/F (17, 5) | 15 | 7 | 12 | 64 ± 6 | 65 ± 5 | 30.6 ± 4.5 | 30.7 ± 4 | L. reuteri DSM 17,938 (low dose) (1*108 CFU/day) | Placebo |
| Mobini et al. (2017) (A), (B) [53] | Sweden | Paralell, R, PC, DB | T2DM | M/F (17, 5) | 14 | 8 | 12 | 66 ± 6 | 65 ± 5 | 32.3 ± 3.4 | 30.7 ± 4 | L. reuteri DSM 17,938 high dose) (1*1010 CFU/day) | Placebo |
| Bahmani et al. (2016) (A), (B) [51] | Iran | Paralell, R, PC, DB | T2DM | M/F (8, 33) | 27 | 14 | 12 | 52 ± 7.2 | 53.4 ± 7.5 | 29.8 ± 5.7 | 30.5 ± 4.1 | Probiotic (L. sporogenes) ((1 £ 108 CFU) 3 times a day) | Bread |
| Bahmani et al. (2016) (A), (B) [51] | Iran | Paralell, R, PC, DB | T2DM | M/F (7, 33) | 27 | 13 | 12 | 51.3 ± 10.4 | 53.4 ± 7.5 | 30.8 ± 5.9 | 30.5 ± 4.1 |
Synbiotic bread (Lactobacillus sporogenes + inulin) ((1 £ 108 CFU + 0.07 g inulin per 1 g) 3 times a day) |
Bread |
| Hove et al. (2015) [19] | Denmark | Paralell, R, PC, DB | T2DM | M (41) | 23 | 18 | 12 | 58.5 ± 7.7 | 60.6 ± 5.2 | 29.2 ± 3.8 | 27.7 ± 3.3 | Milk fermented with L. helveticus (Cardi04 yogurt) (300 ml/day) | Yogurt |
| Kooshki et al. (2015) [23] | Iran | Paralell, R, PC, DB | T2DM | M/F (16, 28) | 22 | 22 | 12 | 53.45 ± 10.8 | 54.5 ± 11.10 | 22.79 ± 2.7 | 22.47 ± 2.38 | Synbiotic (1 tablet day) | Placebo |
| Tonucci et al. (2017) [55] | Brazil | Paralell, R, PC, DB | T2DM | M/F (26, 16) | 23 | 22 | 12 | 51.83 ± 6.64 | 50.95 ± 7.20 | 27.49 ± 3.97 | 27.94 ± 4.15 | Probiotic (mixture) (120 g/d) | Conventional fermented goat milk |
| Asemi et al. (2014) [24] | Iran | Paralell, R, PC, DB | T2DM | M/F (38, 86) | 62 | 62 | 6 | 53.1 ± 8.7 | 58 ± 4.1 | 29.6 ± 4.53 | 29.9 ± 5.18 | Synbiotic (9 g/3 times per day) | Placebo |
| Mohamadshahi et al. (2014) [40] | Iran | Paralell, R, PC, DB | T2DM | M/F (10, 32) | 21 | 21 | 12 | 53 ± 5.9 | 49 ± 7.08 | 28.36 ± 4.14 | 29.22 ± 3.2 | Probiotic (multistrain) (300 g a day) | Yogurt |
| Tajadadi-Ebrahimi et al. (2014) (A) [27] | Iran | Paralell, R, PC, DB | T2DM | M/F (8, 33) | 27 | 14 | 12 | 52 ± 7.2 | 53.4 ± 7.5 | 29.8 ± 5.7 | 30.5 ± 4.1 | Probiotic (L. sporogenes) (40 g 3 times a day) | Bread |
| Tajadadi-Ebrahimi et al. (2014) (B) [27] | Iran | Paralell, R, PC, DB | T2DM | M/F (8, 32) | 27 | 13 | 12 | 51.3 ± 10.4 | 53.4 ± 7.5 | 30.8 ± 5.9 | 30.5 ± 4.1 | Synbiotic (L. sporogenes) + (inulin) (40 g 3 times a day + (0.07 g inulin/g)) | Bread |
| Asemi et al. (2013) [52] | Iran | Paralell, R, PC, DB | T2DM | M/F (15, 39) | 27 | 27 | 8 | 50.51 ± 9.82 | 52.59 ± 7.14 | 31.61 ± 6.36 | 30.17 ± 4.23 | Probiotic (multistrain) (once per day) | Placebo |
| Mazloom et al. (2013) [43] | Iran | Paralell, R, PC, DB | T2DM | M/F (8, 26) | 16 | 18 | 12 | 55.4 ± 8 | 51.8 ± 10.2 | 27.97 ± 3.81 | 27.24 ± 2.73 | Probiotic (multistrain) (1500 mg (twice a day)) | Placebo |
| Ejtahed et al. (2012) [49] | Iran | Paralell, R, PC, DB | T2DM | M/F (23, 37) | 30 | 30 | 12 | 50.87 ± 7.68 | 51 ± 7.32 | 28.95 ± 3.65 | 29.14 ± 4.3 | Probiotic (multistrain) (300 g/day) | Yogurt |
IG intervention group, CG control group, DB double-blinded, SB single-blinded, PC placebo-controlled, CO controlled, RA randomized, NR not reported, F Female, M Male, NR not reported