Table 3.

Subgroup analyses of probiotics and synbiotic supplementation on inflammatory cytokines, oxidative stress and adipokines

	Number of studies	WMD (95%CI)	p value	heterogeneity
				p heterogeneity	I2	p between
Subgroup analyses of probiotic and synbiotic supplementation on CRP
Overall effect	31	− 0.62 (− 0.80, − 0.44)	< 0.001	< 0.001	82.7%
Baseline CRP (mg/l)
< 3	9	− 0.26 (− 0.43, − 0.09)	0.003	0.007	62.3%	0.001
≥ 3	18	− 1.22 (− 1.77, − 0.68)	< 0.001	< 0.001	74.0%
Trial duration (week)
< 12	11	− 038 (− 053, − 0.23)	< 0.001	0.167	29.3%	0.031
≥ 12	20	− 0.73 (− 1.01, − 0.45)	< 0.001	< 0.001	88.0%
Health status
T2DM	30	− 0.67 (− 0.86, − 0.47)	< 0.001	< 0.001	82%	< 0.001
Pre T2DM	1	− 0.15 (− 0.32, 0.02)	0.076	−	0.0%
Supplementation
Probiotic	25	− 0.47 (− 0.64, − 0.30)	< 0.001	< 0.001	79.6%	0.202
Synbiotic	6	− 1.27 (− 2.49, − 0.05)	0.041	< 0.001	82.7%
Baseline BMI (kg/m2)
Normal (18.5–24.9)	4	− 0.39 (− 0.91, 0.14)	0.146	0.182	38.3%	0.285
Overweight (25–29.9)	17	− 0.76 (− 1.03, − 0.48)	< 0.001	< 0.001	86.1%
Obese (> 30)	8	− 1.00 (− 1.58, − 0.43)	0.001	0.016	59.4%
Subgroup analyses of probiotic and synbiotic supplementation on TNF-α
Overall effect	12	− 0.48 (− 0.81, − 0.15)	0.004	< 0.001	84.8%
Trial duration (week)
< 12	3	− 0.86 (− 1.36, − 0.35)	0.001	0.362	1.6%	0.156
≥ 12	9	− 0.41 (− 0.77, − 0.05)	0.023	< 0.001	87.3%
Health status
T2DM	9	− 0.55 (− 0.91, − 0.18)	0.002	< 0.001	88.9%	0.345
Pre T2DM	3	− 0.22 (− 0.79, 0.35)	0.455	0.904	0.0%
Supplementation
Probiotic	11	− 0.47 (− 0.81, − 0.13)	0.006	< 0.001	86.0%	0.697
Synbiotic	1	− 0.68 (− 1.66, 0.30)	0.176	–	0.0%
Baseline BMI (kg/m2)
Normal (18.5–24.9)	5	− 0.88 (− 2.29, 0.52)	0.217	< 0.001	92.3%	0.758
Overweight (25–29.9)	4	− 0.44 (− 0.75, − 0.12)	0.006	0.098	52.4%
Obese (> 30)	1	− 0.30 (− 0.97, 0.37)	0.383	–	–
Subgroup analyses of probiotic and synbiotic supplementation on IL-6
Overall effect	13	− 0.12 (− 0.40, 0.16)	0.391	0.014	52.3%
Trial duration (week)
< 12	5	0.12 (− 0.61, 0.85)	0.749	0.025	64%	0.375
≥ 12	8	− 0.24 (− 0.57, 0.08)	0.146	0.113	39.8%
Health status
T2DM	11	− 0.05 (− 0.46, 0.36)	0.814	0.020	52.9%	0.482
Pre T2DM	2	− 0.27 (− 0.76, 21.86)	0.258	0.088	65.7%
Supplementation
Probiotic	11	− 0.04 (− 0.34, 0.25)	0.772	0.019	53.2%	0.085
Synbiotic	2	− 0.58 (− 1.12, − 0.04)	0.033	0.647	0.0%
Baseline BMI (kg/m2)
Normal (18.5–24.9)	4	− 0.20 (− 0.76, 0.34)	0.461	0.113	49.7%	0.854
Overweight (25–29.9)	5	− 0.20 (− 0.67, 0.26)	0.396	0.102	48.3%
Obese (> 30)	2	0.40 (− 1.70, 2.52)	0.705	0.002	89.9%
Subgroup analyses of probiotic and synbiotic supplementation on Adiponectin
Overall effect	6	0.66 (− 0.44, 1.77)	0.240	0.031	59.4%
Subgroup analyses of probiotic and synbiotic supplementation on leptin
Overall effect	5	− 2.29 (− 5.73, 1.15)	0.192	< 0.001	82.0%
Subgroup analyses of probiotic and synbiotic supplementation on GSH
Overall effect	13	69.80 (33.65, 105.95)	< 0.001	< 0.001	80.5%
Trial duration (week)
< 12	6	119.58 (0.39, 238.76)	0.049	< 0.001	87.2%	0.272
≥ 12	7	47.51 (16.50, 78.52)	0.003	0.001	72.4%
Supplementation
Probiotic	8	68.72 (26.84, 110.61)	0.001	< 0.001	77.2%	0.752
Synbiotic	5	85.14 (− 7.64, 177.92)	0.056	< 0.001	91.7%
Baseline BMI (kg/m2)
Overweight (25–29.9)	8	77.53 (27.47, 127.58)	0.002	< 0.001	81.1%	0.532
Obese	5	58.64 (1.43, 115.84)	0.045	< 0.001	80.6%
Subgroup analyses of probiotic and synbiotic supplementation on MDA
Overall effect	12	− 0.51 (− 0.73, − 0.30)	< 0.001	< 0.001	84.4%
Trial duration (week)
< 12	5	− 0.36 (− 0.77, 0.06)	0.095	< 0.001	81.1%	0.272
≥ 12	7	− 0.60 (− 0.76, − 0.45)	< 0.001	0.031	56.8%
Supplementation
Probiotic	9	− 0.48 (− 0.76, − 0.20)	0.001	< 0.001	87.6%	0.606
Synbiotic	3	− 0.59 (− 0.93, − 0.26)	< 0.001	0.064	63.6%
Baseline BMI (kg/m2)
Overweight (25–29.9)	8	− 0.46 (− 0.77, − 0.16)	0.003	< 0.001	88.1%	0.487
Obese	4	− 0.61 (− 0.87, − 0.35)	< 0.001	0.047	62.3%
Subgroup analyses of probiotic and synbiotic supplementation on TAC
Overall effect	12	73.59 (33.24, 113.95)	< 0.001	< 0.001	83.1%
Trial duration (week)
< 12	5	23.64 (− 8.22, 55.50)	0.146	0.145	41.4%	0.104
≥ 12	7	103.56 (45.28, 161.84)	< 0.001	< 0.001	77.2%
Supplementation
Probiotic	8	85.43 (28.82, 142.04)	0.003	< 0.001	79.0%	0.791
Synbiotic	4	49.76 (− 5.81, 105.33)	0.079	0.010	73.5%
Baseline BMI (kg/m2)
Overweight (25–29.9)	7	98.32 (31.00, 165.65)	0.004	< 0.001	89.9%	0.043
Obese	5	37.02 (5.05, 68.98)	0.023	0.408	0.0%
Subgroup analyses of probiotic and synbiotic supplementation on NO
Overall effect	9	7.49 (3.12, 11.86)	0.001	< 0.001	93.7%
Trial duration (week)
< 12	2	30.20 (8.55, 51.86)	0.006	0.004	87.7%	0.018
≥ 12	7	3.66 (0.06, 7.25)	0.046	< 0.001	91.1%
Supplementation
Probiotic	6	4.52 (0.79, 8.25)	0.018	< 0.001	89.6%	0.216
Synbiotic	3	15.82 (− 1.68, 33.31)	0.076	< 0.001	95.9%
Baseline BMI (kg/m2)
Overweight (25–29.9)	5	3.99 (− 0.24, 8.22)	0.064	< 0.001	74.7%	0.085
Obese	4	12.40 (3.82, 20.98)	0.005	< 0.001	97.1%

CI confidence interval, WMD weighted mean differences, BMI body mss index, CRP c-reactive Protein, TNF-α tumor necrosis factor-α, IL-6 interleukin-6, GSH glutathione, MDA malondialdehyde, TAC total antioxidant capacity, NO nitric oxide, T2DM type 2 diabetes mellitus