Table 1 The characteristics of trials that investigated the effect of probiotic/synbiotic supplementation on anthropometric indices in patients with diabetes and were eligible for inclusion in the meta-analysis

Arani, 2019 (31)/ Iran

60, Both / 61.5

P/ 12

Type 2/ Diabetic

nephropathy

Probiotic honey: B. coagulans T11(2.5 × 10⁹)

Weight, BMI

No significant change

Asemi, 2014

(32)/ Iran

62, Both / 50.90

 C/ 6¹

Type 2/ -

Synbiotic: L. sporogenes (2.7 10⁸) + Inulin

Weight, BMI,

No significant change

Asemi, 2013 (33)/ Iran

58, Both / 55.94

P/ 8

Type 2/ -

Probiotic: L. acidophilus (2 × 10⁹), L. casei (7 × 10⁹), L. rhamnosus (1.5 × 10⁹), L. bulgaricus (2 × 10⁸), B.breve (2 × 10¹⁰), B. longum (7 × 10⁹), S. thermophilus (1.5 × 10⁹)

Weight, BMI

No significant change

Barthow, 2022 (26)/ New Zealand

143, Both/ 60

P/ 26

Prediabetes/ -

Probiotic: L.rhamnosus (HN001) (6 × 10⁹ colony-forming units/day)

Weight, BMI, WC

No significant change

Firouzi, 2016 (35)/ Malaysia

101, Both / 53.82

P/ 6 &12

Type 2/ -

Probiotic: L. acidophilus BCMC 12,130 (10¹⁰), L. casei BCMC 12,313 (10¹⁰), L. lactis BCMC 12,451 (10¹⁰), B.bifidum BCMC 02290 (10¹⁰), B. Longum BCMC 02120 (10¹⁰), B.infantis BCMC 02129 (10¹⁰)

Weight, BMI, WC

No significant change

Horvath, 2019 (36)/ Austria

26, Both / 59.92

P/ 12 &26

Type 2/ -

Synbiotic: B. bifidum W23, B. lactis W51, B. lactis W52, L. acidophilus W37, L. casei W56, L. brevis W63, L. salivarius W24, L. lactis W58, L. lactis W19 (totally 1.5 × 10¹⁰)/ Galacto-oligosaccharides P11, Fructo-oligosaccharides P6 + konjac glucomannan P13 (E425), calcium carbonate (E170), zinc citrate 3-hydrate, vitamin D3 and vitamin B2 (E101)

Weight, BMI, WC, HC, WHR

Significant decrease in HC in synbiotic group after 12 weeks of intervention

Hosseinzadeh, 2013 (53)/ Iran

84, Both / 46.25

P/ 12¹

Type 2/ -

Brewer’s Yeast (1800 mg)

BMI

No significant change

Hove, 2015 (37)/ Denmark

41, M/ 59.42

P/ 12

Type 2/ -

Fermented milk: L. helveticus Cardi04

Weight, BMI, WC, HC

No significant change

Kanazawa, 2021(27)/ Japan

86, Both/ 56

P/ 24

Type 2/ -

Synbiotic: 3.0 g dry powder containing at least 3 × 108 living L.paracasei YIT 9029 (strain Shirota:LcS) organisms, 3 × 108 living B.breve YIT 12,272 (BbrY) organisms, and 7.5 g GOS per day

BMI

No significant change

Kassaian, 2019 (54)/ Iran

86, Both / 52.97

P/ 12 &26

Prediabetes/ -

Probiotic: L. acidophilus (1.5 × 10⁹), B.bifidum (1.5 × 10⁹), B. lactis (1.5 × 10⁹), B. longum (1.5 × 10⁹)

Synbiotic: Inulin + L. acidophilus (1.5 × 10⁹), B.bifidum (1.5 × 10⁹), B. lactis (1.5 × 10⁹), B. longum (1.5 × 10⁹)

BMI

No significant change

Khalili, 2019 (38)/ Iran

40, Both / 44.75

P/ 8

Type 2/ -

Probiotic: L. casei 01 (10⁸)

Weight, BMI, WC, WHR

Significant decrease in Weight, BMI, WC in probiotic group

Kobyliak, 2018 (39)/ Ukraine

53, Both / 54.28

P/ 8

Type 2/ -

Probiotic: Bifidobacterium (1 × 10¹¹), Lactobacillus, Lactococcus (6 × 10¹¹), Propionibacterium (3 × 10¹¹)

Weight, BMI, WC

Significant decrease in WC in probiotic group compared to placebo

Kooshki, 2015 (40)/ Iran

43, Both / 54.88

P/ 8

Type 2/ -

Synbiotic: B. coagulants (1.5 × 10⁷) + Fructo-oligosaccharides

Weight, BMI

Significant decrease in weight and BMI in synbiotic group compared to placebo

Madempudi, 2019 (41)/ India

74, Both / 52.05

P/ 12²

Type 2/ -

Probiotic: L. salivarius UBLS22, L. casei UBLC42, L. plantarum UBLP40, L. acidophilus UBLA34, B. breve UBBr01, B. coagulans Unique IS2 (totally 6 × 10¹⁰)

Weight

Significant decrease in weight in probiotic group compared to placebo

Mafi, 2018 (42)/ Iran

60, Both / 59.9

P/ 12

Type 1&2/ Nephropathy

Probiotic: L. acidophilus ZT-L1 (2 × 10⁹), B.bifidum ZT-B1(2 × 10⁹), L. reuteri ZT(2 × 10⁹), L. fermentum ZT-L3(2 × 10⁹)

Weight, BMI

No significant change

Miraghajani, 2017 (43)/ Iran

40, Both / 55.25

P/ 8

Type 2/ Nephropathy

Probiotic soy milk: L. plantarum A7 (4 × 10⁹)

Weight, BMI, WHR

No significant change

Mobini, 2017(44)/ Sweden

44, Both / 65

P/ 12

Type 2/ -

Probiotic (Low & high dose): L. reuteri DSM 17,938 (10⁸) or (10¹⁰)

Weight, BMI, WC, Body fat

Significant increase in weight

in low dose probiotic group

Mohamadshahi, 2014 (45)/ Iran

44, Both / 51

P/ 8

Type 2/ -

Probiotic yogurt: B.animalis subsp. lactis Bb12 (DSM 10,140), L. acidophilus La5 (Totally 11.1 × 10⁸)

Weight, BMI, WC, HC, WHR, Body fat

No significant change

Mohseni, 2018 (46)/ Iran

60, Both / 60.55

P/ 12

Type 1&2/ Diabetic foot ulcer

Probiotic: L. acidophilus (2 × 10⁹), L. casei (2 × 10⁹), L. Fermentum (2 × 10⁹), B. bifidum (2 × 10⁹)

Weight, BMI

No significant change

Naito, 2017 (47)/ Japan

98, Both / 47.01

P/ 4& 8

Prediabetes/ -

Fermented milk: L. casei Shirota YIT 9029 (1 × 10¹¹)

Weight, BMI, Body fat

No significant change

Razmpoosh, 2018 (48)/ Iran

60, Both / 59.95

P/ 6²

Type 2/ -

Probiotics: L. acidophilus (2 × 10⁹), L. casei (7 × 10⁹), L. rhamnosus (1.5 × 10⁹), L. bulgaricus (2 × 10⁸), B.breve (3 × 10¹⁰), B.longum (7 × 10⁹), S. thermophiles (1.5 × 10⁹)

Weight, BMI, WC, HC

No significant change

Rustanti, 2022(28)/ Indonesia

36, F/ 44.11

P/ 11

Type 2/ -

Skim milk powder containing L.plantarum Dad-13 (1010 CFU)

Weight, BMI, WC, HC, WHR

No significant change

Sabico, 2017 (52)/ Saudi Arabia

78, Both / 47.3

P/ 12²

Type 2/ -

Probiotics: B.bifidum W23, B.lactis W52, L. acidophilus W37, L. brevis W63, L. casei W56, L. salivarius W24, L¹. lactis W19, La. lactis W58 (totally 5 × 10⁹)

Weight, BMI, WHR

Significant decrease in WHR in probiotic group compared to placebo

Sabico, 2018 (55)/ Saudi Arabia

61, Both / 47.3

P/ 12 & 26²

Type 2/ -

Probiotics: B.bifidum W23, B. lactis W52, L. acidophilus W37, L. brevis W63, L. casei W56, L. salivarius W24, L¹. lactis W19, La. lactis W58 (totally 5 × 10⁹)

BMI, WHR

No significant change

Sahin, 2022 (29)/ Turkey

126, Both/ 50.8

P/ 4

Prediabetes and Type 2/ -

Probiotics: B. animalis subsp.lactis (BB-12)(4.6 mg)

Weigh, BMI

No significant change

Sato, 2017 (56)/ Japan

68, Both / 64.5

P/ 8 &16

Type 2/ -

Fermented milk: L. casei Shirota (4 × 10¹⁰)

BMI

No significant change

Soleimani, 2016 (49)/ Iran

60, Both / 56.7

P/ 12

Type 1&2/ Hemodialysis

Probiotic: L. Acidophilus (2 × 10⁹), L. casei (2 × 10⁹), B.bifidum (2 × 10⁹)

Weight, BMI

No significant change

Tajabadi-Ebrahimi, 2014 (50)/ Iran

81, Both / 52.35

P/ 8¹

Type 2/ -

Probiotic bread: L. sporogenes (1 × 10⁸)

Synbiotic bread: / L. sporogenes (1.2 × 10⁸) + Inulin

Weight, BMI

No significant change

Tajabadi-Ebrahimi, 2017 (34)/ Iran

60, Both / 64.1

P/ 12

Type 2/ coronary heart disease

Synbiotic: L. acidophilus (2 × 10⁹), L. casei (2 × 10⁹), B.bifidum (2 × 10⁹) + Inulin

Weight, BMI

No significant change

Toshimitsu, 2020 (51)/ Japan

126, Both/ 50.91

P/ 12

Pre-diabetes/ -

Probiotic yogurts: L. plantarum OLL2712 (5 × 10⁹)

Weight, BMI

No significant change

Velayati, 2021(30)/ Iran

43, Both/ 60.31

P/ 12

Type 2/ -

Probiotic: B. Coagulans GanedenBC30 (2 × 10¹¹), L.rhamnosus GG (2 × 10¹⁰), L. acidophilus and 500 mg fructo oligosaccharide and 0.7% Natural Orange flavor

Weight, BMI, Waist, HC

No significant change