Introduction
Methods
Search strategy
Inclusion and exclusion criteria
Data extraction and quality assessment
Data synthesis and statistical analysis
Results
Study characteristics
First author, year | Country | Sample size | Age, years (mean ± SD) | BMI, kg/m2 (mean ± SD) | Study design | Type of vehicles for probiotics | Probiotics (genus and daily dose) | Duration (weeks) | |||
---|---|---|---|---|---|---|---|---|---|---|---|
P | C | P | C | P | C | ||||||
Toejing, 2021 [27] | Thailand | 18 | 18 | 63.5 ± 5.9 | 61.8 ± 7.7 | 23.22 ± 2.72 | 23.05 ± 2.60 | DB, PC | Powder | L. paracasei HII01 (5 × 1010 CFU/day) | 12 |
Zhang, 2020 [15] | China | 102 | 103 | 52.6 ± 10.5 | 53.6 ± 11.3 | 25.60 ± 2.96 | 26.20 ± 3.43 | DB, PC | Powder | Probiotics mixture of (5 × 1010 CFU/day, Bifidobacterium longum BL88-Onlly, Bifido -bacterium breve BB8, Lactococcus gasseri LG23, Lactobacillus rhamnosus LR22, Lactobacillus salivarius LS86, Lactobacillus crispatus LCR15, Lactobacillus plantarum LP-Onlly, Lactobacillus fermentum LF33, Lactobacillus casei LC18) | 13 |
Palacios, 2020 [46] | Australia | 30 | 30 | 61.4 ± 8.9 | 56.1 ± 12.3 | 35.50 ± 6.20 | 36.30 ± 7.50 | DB, PC | Capsule | Probiotics mixture of Lactobacillus plantarum Lp-115 1 (2 × 1010 CFU/day), Lacto -bacillus bulgaricus Lb-64 (6 × 109 CFU/day), Lactobacillus gasseri Lg-36 (3.6 × 1010 CFU/day), Bifidobacterium breve Bb-03 (1.5 × 1010 CFU/day), Bifidobacterium animalis sbsp. lactis Bi-07 (1.6 × 1010 CFU/day), Bifidobacterium bifidum Bb-06 (1.4 × 1010 CFU/day), Streptococcus thermophilus St-21 (9 × 108 CFU/day), Saccharomyces boulardii DBVPG 6763 (9 × 107 CFU /day) | 12 |
Lsmail, 2020 [44] | Egypt | 50 | 50 | 48.3 ± 12.9 | 46.4 ± 13.2 | 31.10 ± 5.30 | 30.20 ± 6.00 | PC | Yogurt | Bifidobacterium animalis dn-173 010 (NR) | 16 |
Tipici, 2020 [23] | Turkey | 17 | 17 | NR | NR | 35.51 ± 7.33 | 33.65 ± 6.17 | PC | NR | Lactobacillus GG (1 × 1010 CFU/day) | 8 |
Jiang, 2020 [16] | China | 42 | 34 | 56.0 ± 8.5 | 56.1 ± 8.2 | 27.51 ± 3.22 | 26.44 ± 2.78 | DB, PC | Capsule | Probiotics mixture of (Bifidobacterium bifidum (1.2 × 109 CFU/day), Lactobacillus acidophilus (4.2 × 109 CFU/day), Streptococcus thermophilus (4.3 × 109 CFU/day)) | 12 |
Sabico, 2019 [43] | Saudi Arabia | 31 | 30 | 48.0 ± 8.3 | 46.6 ± 5.9 | 30.10 ± 5.00 | 29.40 ± 5.20 | DB, PC | Powder | Probiotics mixture of (4 × 109 CFU/day, Bifidobacterium bifidum W23, Bifidobacterium lactis W52, Lactobacillus acidophilus W37, Lactobacillus brevis W63, Lactobacillus casei W56, Lactobacillus salivarius W24, Lactococcus lactis W19 and Lactobacillus lactis W58) | 24 |
Razmpoosh, 2019 [12] | Iran | 30 | 30 | 58.6 ± 6.5 | 61.3 ± 5.2 | 27.70 ± 4.20 | 27.20 ± 4.20 | DB, PC | Capsule | Probiotics mixture of (Lactobacillus acidophilus (4 × 109 CFU/day) Lactobacillus casei (1.4 × 1010 CFU/day), Lactobacillus rhamnosus (3 × 109 CFU/day), Lactobacillus bulgaricus (4 × 108 CFU/day), Bifidobacterium breve (6 × 1010 CFU/day), Bifidobacterium longum (1.4 × 1010 CFU/day), Streptococcus thermophilus (3 × 109 CFU/day)) | 6 |
Khalili, 2019 [33] | Iran | 20 | 20 | 44.0 ± 8.1 | 45.0 ± 5.4 | 29.50 ± 3.34 | 31.94 ± 5.76 | DB, PC | Capsule | cfu L. casei (1 × 108 CFU/day) | 8 |
Madempudi, 2019 [25] | India | 40 | 39 | 54.1 | 50.6 | NR | NR | DB, PC | Capsule | Probiotics mixture of (6 × 1010 CFU/day, L. salivarius UBLS22, L. casei UBLC42, L. plantarum UBLP40, L. acidophilus UBLA34, B. breve UBBr01, and B. coagulans Unique IS2) | 12 |
Raygan, 2018 [39] | Iran | 30 | 30 | 60.7 ± 9.4 | 61.8 ± 9.8 | 30.30 ± 5.20 | 29.30 ± 4.10 | DB, PC | Capsule | Probiotics mixture of (Bifidobacterium bifidum (2 × 109 CFU/day), Lactobacillus casei (2 × 109 CFU/day), Lactobacillus acidophilus (2 × 109 CFU/day)) | 12 |
Hsieh, 2018 [24] | China | 22 | 22 | 52.3 ± 10.2 | 55.8 ± 8.6 | 28.04 ± 4.29 | 27.53 ± 3.15 | DB, PC | Capsule | Lactobacillus reuteri ADR-1 (4 × 109 CFU/day) | 36 |
Kobyliak, 2018 [41] | Ukraine | 31 | 22 | 52.2 ± 1.7 | 57.18 ± 2.06 | 34.70 ± 1.29 | 35.65 ± 1.57 | DB, PC | NR | Probiotics mixture of (Lactococcus (6 × 1011 CFU/day), Bifidobacterium (1 × 1011 CFU/day), Propionibacterium (3 × 1011 CFU/day), Acetobacter (1 × 107 CFU/day)) | 8 |
Sato, 2017 [28] | Japan | 34 | 34 | 64.0 ± 9.2 | 65.0 ± 8.3 | 24.20 ± 2.60 | 24.60 ± 2.60 | DB, PC | Fermented milk | Lactobacillus casei strain Shirota (4 × 1010 CFU/day) | 16 |
Mobini, 2017 [42] | Sweden | 14 | 15 | 64.0 ± 6.0 | 65.0 ± 5.0 | 32.30 ± 3.40 | 30.70 ± 4.00 | DB, PC | Tablet | Lactobacillus reuteri DSM 17938 (1 × 1010 CFU/day) | 12 |
Firouzi, 2017 [29] | Malaysia | 48 | 53 | 52.9 ± 9.2 | 54.2 ± 8.3 | 29.20 ± 5.60 | 29.30 ± 5.30 | DB, PC | Powder | Probiotics mixture of (6 × 1010 CFU/day, Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus lactis, Bifidobacterium bifidum, Bifidobacterium longum, Bifidobacterium infantis) | 12 |
Feizollahzadeh, 2017 [32] | Iran | 20 | 20 | 56.9 ± 8.1 | 53.6 ± 7.2 | 26.68 ± 3.18 | 26.58 ± 3.24 | DB, PC | Soy milk | Lactobacillus planetarum A7 (2 × 107 CFU/day) | 8 |
Tonucci, 2017 [47] | Brazil | 23 | 22 | 51.8 ± 6.6 | 51.0 ± 7.2 | 27.49 ± 3.97 | 27.94 ± 4.15 | DB, PC | Fermented milk | Probiotics mixture of (Lactobacillus acidophilus La-5 (1 × 109 CFU/day), Bifidobacterium animalis subsp. lactis BB-12 (1 × 109 CFU/day)) | 6 |
Bayat, 2016 [31] | Iran | 20 | 20 | 54.1 ± 9.5 | 47.0 ± 9.3 | 28.77 ± 4.59 | 29.75 ± 4.66 | PC | Yogurt | NR | 8 |
Ostadrahimi, 2015 [48] | Brazil | 30 | 30 | NR | NR | 28.89 ± 4.77 | 27.47 ± 3.55 | DB, PC | Fermented milk | Bifidobacterium animalis HN019 2.7 (2 × 1010 CFU/day) | 8 |
Hove, 2015 [45] | Denmark | 23 | 18 | 58.5 ± 7.7 | 60.6 ± 5.2 | 29.20 ± 3.80 | 27.70 ± 3.30 | DB, PC | Fermented milk | Lactobacillus helveticus Cardi04 (NR) | 12 |
Tajadadi-Ebrahimi, 2014 [36] | Iran | 27 | 27 | 52.0 ± 7.2 | 53.4 ± 7.5 | 29.80 ± 5.70 | 30.50 ± 4.10 | DB, PC | Bread | Lactobacillus Sporogenes (3 × 108 CFU/day) | 8 |
Shakeri, 2014 [35] | Iran | 26 | 26 | 52.3 ± 8.2 | 53.1 ± 7.5 | 29.50 ± 5.70 | 30.60 ± 4.10 | DB, PC | Bread | L. Sporogenes (1.2 × 1010 CFU/day) | 8 |
Mohamadshahi, 2014 [34] | Iran | 22 | 22 | 53.0 ± 5.9 | 49.0 ± 7.1 | 28.36 ± 4.14 | 29.22 ± 3.20 | DB, PC | Yogurt | Probiotics mixture of (Lactobacillus acidophilus (1.11 × 109 CFU/day), Bifidobacterium lactic (1.11 × 109 CFU / day)) | 8 |
Jung, 2014 [30] | Korea | 21 | 20 | 63.3 ± 9.2 | 60.2 ± 8.5 | 25.90 ± 4.12 | 25.60 ± 3.13 | DB, PC | Milk | probiotics mixture of (Lactobacillus acidophilus (3 × 1010 CFU/day), Lactobacillus casei (1.8 × 1010 CFU/day), Bifidobacterium lactis (9.6 × 1010 CFU/day), Streptococcus thermophilus (NR)) | 8 |
Judiono, 2014 [26] | Indonesian | 36 | 36 | NR | NR | NR | NR | PC | Milk | Probiotics mixture of (lactic acid bacterias (2 × 109 CFU/day), and other 34 beneficial heal -thy probiotic bacterias (NR)) | 4 |
Mazloom, 2013 [38] | Iran | 16 | 18 | 55.4 ± 8.0 | 51.8 ± 10.2 | 27.97 ± 3.81 | 27.24 ± 2.73 | SB, PC | Capsule | Probiotics mixture of (Lactobacillus acidophilus (NR), Lactobacillus bulgaricus (NR), Lactobacillus bififi dum (NR), Lactobacillus casei (NR)) | 6 |
Asemi, 2013 [11] | Iran | 27 | 27 | 50.5 ± 9.8 | 52.6 ± 7.1 | 31.61 ± 6.36 | 30.17 ± 4.23 | DB, PC | Capsule | probiotics mixture of (L. acidophilus (2 × 109 CFU/day), L. casei (7 × 109 CFU/day), L. rha -mnosus (1.5 × 109 CFU/day), L. bulgaricus (2 × 108 CFU/day), Bifidobacterium breve (2 × 1010 CFU/day), B. longum (7 × 109 CFU/day), Streptococcus thermophilus (1.5 × 109 CFU/day)) | 8 |
Hosseinzadeh, 2013 [40] | Iran | 42 | 42 | 46.8 ± 6.2 | 45.7 ± 6.1 | 30.00 ± 4.40 | 29.90 ± 4.70 | DB, PC | Tablet | NR | 12 |
Ejtahed, 2012 [37] | Iran | 30 | 30 | 50.9 ± 7.7 | 51.0 ± 7.3 | 28.95 ± 3.65 | 29.14 ± 4.30 | DB, PC | Yogurt | Probiotics mixture of (Lactobacillus acidophilus La5 (2.2 × 109 CFU), Bifidobacterium lactis Bb12 (1.8 × 109 CFU), Lactobacillus bulgaricus (NR), Streptococcus thermophilus (NR)) | 6 |
Risk of bias assessment of the included RCTs
Effects of probiotic supplementation on glycaemic control
Effects on FBG
Subgroup | No. of trials | No. of participants | I2 (%) | Pheterogeneity | Pooled SMD [95% CI] | Peffect | Psubgroup |
---|---|---|---|---|---|---|---|
Race | |||||||
Asian | 9 | 722 | 18.5 | 0.279 | − 0.217 [− 0.364, − 0.070] | 0.004 | 0.020 |
Caucasian | 19 | 1000 | 24.8 | 0.157 | − 0.448 [− 0.575, − 0.322] | < 0.001 | |
Dose of probiotics | |||||||
≤ 1 × 1010 CFU/day | 12 | 643 | 38.8 | 0.082 | − 0.335 [− 0.500, − 0.170] | 0.003 | 0.412 |
> 1 × 1010 CFU/day | 13 | 885 | 0.0 | 0.203 | − 0.248 [− 0.376, − 0.119] | < 0.001 | |
Duration of intervention | |||||||
≤ 8 weeks | 16 | 783 | 0.0 | 0.541 | − 0.300 [− 0.441, − 0.158] | < 0.001 | 0.506 |
> 8 weeks | 14 | 1044 | 52.9 | 0.010 | − 0.401 [− 0.588, − 0.215] | < 0.001 | |
Genus of probiotics | |||||||
Lactobacillus | 11 | 472 | 0.0 | 0.669 | − 0.194 [− 0.376, − 0.012] | 0.037 | 0.040 |
Bifidobacterium | 2 | 160 | 69.9 | 0.068 | − 0.626 [− 1.221, − 0.030] | 0.039 | |
Lactobacillus and Bifidobacterium | 15 | 1071 | 32.1 | 0.111 | − 0.346 [− 0.498, − 0.195] | < 0.001 | |
Type of vehicle used to deliver the probiotics | |||||||
Powder/capsule/tablet | 15 | 1023 | 36.4 | 0.078 | − 0.357 [− 0.481, − 0.232] | < 0.001 | 0.809 |
Food | 13 | 717 | 35.1 | 0.102 | − 0.333 [− 0.481, − 0.184] | < 0.001 | |
Baseline BMI | |||||||
< 30 kg/m2 | 16 | 995 | 2.8 | 0.420 | − 0.218 [− 0.343, − 0.092] | 0.001 | 0.007 |
≥ 30 kg/m2 | 12 | 681 | 40.6 | 0.070 | − 0.490 [− 0.644, − 0.336] | < 0.001 |
Effects on insulin
Subgroup | No. of trials | No. of participants | I2 (%) | Pheterogeneity | Pooled SMD [95% CI] | Peffect | Psubgroup |
---|---|---|---|---|---|---|---|
Race | |||||||
Asian | 5 | 313 | 0.0 | 0.777 | − 0.145 [− 0.367, 0.078] | 0.202 | 0.764 |
Caucasian | 11 | 513 | 23.3 | 0.222 | − 0.187 [− 0.352, − 0.022] | 0.027 | |
Dose of probiotics | |||||||
≤ 1 × 1010 CFU/day | 9 | 516 | 27.2 | 0.202 | − 0.169 [− 0.343, 0.005] | 0.056 | 0.851 |
> 1 × 1010 CFU/day | 6 | 323 | 0.0 | 0.673 | − 0.143 [− 0.362, 0.076] | 0.202 | |
Duration of intervention | |||||||
≤ 8 weeks | 10 | 478 | 0.0 | 0.693 | − 0.291 [− 0.463, − 0.120] | 0.001 | 0.071 |
> 8 weeks | 7 | 408 | 1.1 | 0.416 | − 0.052 [− 0.247, 0.143] | 0.600 | |
Genus of probiotics | |||||||
Lactobacillus | 6 | 356 | 21.1 | 0.275 | − 0.300 [− 0.510, − 0.090] | 0.005 | 0.183 |
Lactobacillus and Bifidobacterium | 10 | 584 | 0.0 | 0.661 | − 0.119 [− 0.282, 0.044] | 0.152 | |
Type of vehicle used to deliver the probiotics | |||||||
Powder/capsule/tablet | 10 | 510 | 0.0 | 0.630 | − 0.049 [− 0.223, 0.125] | 0.581 | 0.014 |
Food | 6 | 316 | 0.0 | 0.744 | − 0.386 [− 0.592, − 0.180] | < 0.001 | |
Baseline BMI | |||||||
< 30 kg/m2 | 8 | 413 | 0.0 | 0.732 | − 0.261 [− 0.455, − 0.066] | 0.009 | 0.279 |
≥ 30 kg/m2 | 8 | 448 | 31.2 | 0.179 | − 0.112 [− 0.299, 0.075] | 0.239 |
Effects on HbA1c
Subgroup | No. of trials | No. of participants | I2 (%) | Pheterogeneity | Pooled SMD [95% CI] | Peffect | Psubgroup |
---|---|---|---|---|---|---|---|
Race | |||||||
Asian | 9 | 722 | 70.2 | 0.001 | − 0.362 [− 0.647, − 0.077] | 0.013 | 0.032 |
Caucasian | 12 | 639 | 39.6 | 0.077 | − 0.465 [− 0.672, − 0.257] | < 0.001 | |
Dose of probiotic | |||||||
≤ 1 × 1010 CFU/day | 8 | 368 | 5.0 | 0.392 | − 0.337 [− 0.573, − 0.102] | < 0.001 | 0.076 |
> 1 × 1010 CFU/day | 11 | 833 | 62.8 | 0.003 | − 0.484 [− 0.699, − 0.270] | 0.005 | |
Duration of intervention | |||||||
≤ 8 weeks | 11 | 543 | 0.0 | 0.586 | − 0.509 [− 0.681, − 0.337] | < 0.001 | 0.077 |
> 8 weeks | 12 | 923 | 72.4 | < 0.001 | − 0.359 [− 0.619, − 0.098] | 0.007 | |
Genus of probiotics | |||||||
Lactobacillus | 7 | 292 | 54.1 | 0.042 | − 0.250 [− 0.599, 0.098] | 0.159 | 0.001 |
Bifidobacterium | 2 | 160 | 50.7 | 0.154 | − 0.913 [− 1.387, − 0.438] | < 0.001 | |
Lactobacillus and Bifidobacterium | 12 | 890 | 51.0 | 0.021 | − 0.407 [− 0.605, − 0.209] | < 0.001 | |
Type of vehicle used to deliver the probiotics | |||||||
Powder/capsule/tablet | 11 | 808 | 55.9 | 0.012 | − 0.384 [− 0.606, − 0.162] | 0.001 | 0.047 |
Food | 10 | 571 | 61.5 | 0.005 | − 0.524 [− 0.800, − 0.249] | < 0.001 | |
Baseline BMI | |||||||
< 30 kg/m2 | 13 | 861 | 51.1 | 0.017 | − 0.338 [− 0.541, − 0.134] | 0.001 | 0.018 |
≥ 30 kg/m2 | 8 | 454 | 57.6 | 0.021 | − 0.485 [− 0.783, − 0.188] | 0.001 |
Effects on the HOMA-IR score
Subgroup | No. of trials | No. of participants | I2 (%) | Pheterogeneity | Pooled SMD [95% CI] | Peffect | Psubgroup |
---|---|---|---|---|---|---|---|
Race | |||||||
Asian | 5 | 470 | 39.0 | 0.161 | − 0.139 [− 0.321, 0.043] | 0.134 | 0.173 |
Caucasian | 11 | 601 | 47.3 | 0.040 | − 0.308 [− 0.471, − 0.146] | < 0.001 | |
Dose of probiotics | |||||||
≤ 1 × 1010 CFU/day | 6 | 304 | 69.2 | 0.006 | − 0.179 [− 0.593, 0.234] | 0.396 | 0.969 |
> 1 × 1010 CFU/day | 8 | 653 | 33.3 | 0.163 | − 0.241 [− 0.438, − 0.043] | 0.017 | |
Duration of intervention | |||||||
≤ 8 weeks | 8 | 381 | 32.7 | 0.167 | − 0.163 [− 0.412, 0.085] | 0.198 | 0.496 |
> 8 weeks | 9 | 735 | 52.4 | 0.032 | − 0.312 [− 0.534, − 0.091] | 0.006 | |
Genus of probiotics | |||||||
Lactobacillus | 5 | 213 | 43.8 | 0.130 | − 0.101 [− 0.373, 0.170] | 0.606 | 0.345 |
Lactobacillus and Bifidobacterium | 11 | 819 | 48.4 | 0.036 | − 0.248 [− 0.387, − 0.109] | 0.004 | |
Type of vehicle used to deliver the probiotics | |||||||
Powder/capsule/tablet | 12 | 882 | 57.7 | 0.007 | − 0.239 [− 0.453, − 0.026] | 0.028 | 0.912 |
Food | 4 | 181 | 0.0 | 0.829 | − 0.230 [− 0.523, 0.063] | 0.124 | |
Baseline BMI | |||||||
< 30 kg/m2 | 8 | 571 | 11.9 | 0.338 | − 0.165 [− 0.347, 0.017] | 0.075 | 0.144 |
≥ 30 kg/m2 | 8 | 466 | 60.0 | 0.015 | − 0.320 [− 0.615, − 0.026] | 0.033 |