Probiotics as a Complementary Therapy for Management of Obesity: A Systematic Review

Table 1

Included meta-analysis studies investigating the effect of probiotics on obesity. Probiotic foods consisted of fermented foods that naturally contain probiotics or foods which have probiotics added to them.

Authors/published year	Included studies in meta-analysis (n)	Type of included studies in meta-analysis	Total sample size (n)	Participants’ characteristics	Type and dose of intervention	Duration of interventions (weeks)	Main outcomes	Risk of bias assessment	Reported side effects	AMSTAR score
Hadi et al., 2020	3 (all in Iran)	RCTs	180 (intervention: UN, control: UN)	Women with PCOS ≥18 y	Different species of probiotic supplements (10^9 CFU/day)	12	−Sig. ↓weight: −1.3 kg (95% CI: −1.93, −0.13)	Yes	No side effects	7
							−Sig. ↓BMI; −0.36 kg/m^2 (95% CI: −0.74, 0.02)
Company et al., 2020	17 (11 in Asian countries, 6 in European countries, 1 in Brazil)	DBRCTs	1,106 (intervention: 486, placebo: 62)	Cardio-metabolic disease subjects with obesity, adults ≥18 y, both sexes	Multiple and single species of probiotic supplements within powder and capsule (10^8–10^11 CFU/day)	4–12	−sig. ↓BW: −0.26 kg (95% CI: −0.43, −0.09)	Yes	No side effects	11
							−sig. ↓BMI: −0.35 kg/m^2 (95% CI: −0.48, −0.22)
							−sig. ↓WC: −0.37 cm (95% CI: −0.52, −0.21)
							−sig. ↓BFM: −0.30 kg (95% CI: −0.48, −0.12)
Cao et al., 2020	31 (22 in Asian countries, 6 in European countries, 3 in Brazil)	RCTs	2051 (intervention: UN, control: UN)	Obese and overweight adults ≥18 y, both sexes	Probiotic foods and supplements and dairy product (10^8–10^11 CFU/day)	3–12	−sig. ↓BMI: −0.25 kg/m^2 (95% CI: −0.33, −0.17)	Yes	No side effects	9
							−sig. ↓WC: −0.99 cm (95% CI: −1.33, −0.66)
Xiao M et al., 2019	12 (9 in Asian countries, 3 in European countries)	DBRCTs	693 (intervention: UN, control: UN)	Adults with nonalcoholic fatty liver disease, both sexes	Different species of probiotic supplements (UN amounts)	8–24	−sig. ↓BMI: −1.46 kg/m^2 (95% CI: −2.44, −0.48)	Yes	No serious side effects	10
Wang et al., 2019	12 (9 in Asian countries, 2 in European countries, 1 in Brazil)	DBRCTs, SBRCTs	821 (intervention: 405, control: 416)	Adults with BMI ≥25 and ≥18 y, both sexes	Multiple and single species of probiotic supplements (10^7–10^11 CFU/day)	8–26	−sig. ↓BW: −0.55 kg (95% CI: −0.91, −0.19)	Yes	No side effects	9
							−sig. ↓BMI: − 0.30 kg/m^2 (95% CI: −0.43, −0.18)
							−sig. ↓WC: −1.20 cm (95%CI: −2.21, −0.19)
							−sig. ↓BFM: −0.91 kg (95% CI: −1.19, −0.63)
Tang et al., 2019	12 (7 in Asian countries, 4 in European countries, 1 in Brazil)	DBRCTs	805 (intervention: 407, control 398)	Adults with nonalcoholic fatty liver disease, both sexes	Multiple and single species of probiotic supplements (varied amounts)	8–24	−sig. ↓BW: −2.31 kg (95% CI: −4.45, −0.16) sig. ↓BMI: −1.08 kg/m^2 (95% CI: −2.05, −0.11)	Yes	No side effects	10
Tabrizi et al., 2019	7 (all in Iran)	RCTs	415 (intervention: 212, control: 213)	Women with PCOS ≥18 y	Probiotic capsule supplements (10^8–10^10 CFU/day)	8–12	−sig. ↓BW: −0.30 kg (95% CI: −0.53, −0.07)	Yes	No side effects	9
							−sig. ↓BMI: −0.29 kg/m^2 (95% CI: −0.54, −0.03)
Liu et al., 2019	4 (2 in Iran, 2 in European countries)	RCTs	218 (intervention: 110, control: 108)	Adults with nonalcoholic fatty liver disease ≥18 y, both sexes	Different species of probiotic supplement (varied amounts)	8–12	No significant effect on BMI or WC	Yes	Rare and mild reverse reactions	9
Koutinkova et al., 2019	68 (26 in Iran)	RCTs, COTs	4015 (intervention: UN, control: UN)	Overweight/obese/normal weight adults, both sexes	Multiple and single species of probiotic products (varied amounts)	2–28	−sig. ↓BW: −0.39 kg (95% CI: −0.57, −0.21)	Yes	No side effects	11
							−sig. BMI: −0.33 kg/m^2 (95% CI: −0.53, −0.12)
							−sig. WC: −1.01 cm (95% CI: −1.55, −0.48)
							−sig. BFM: −0.62 kg (95% CI: −0.91, −0.34)
Dong et al., 2019	6 (UN countries)	DBRCTs	476 (intervention: UN, control: UN)	Adults with BMI ≥25 and ≥18 y, both sexes	Probiotic capsules and probiotic dairy products (10^6–10^11 CFU/day)	8–24	No significant effect on BMI or BFM	Yes	No side effects	11
							−sig. ↓WC: −0.35 cm (95% CI: −0.81, 0.11)
John et al., 2018	18 (15 in Asian countries, 1 in Finland, 1 in Brazil, 1 in Canada)	RCTs	803 (intervention: 443, control: 360	Adults ≥18 y with BMI ≥25, both sexes	Multiple and single species of probiotic food or supplements (10^7–10^11 CFU/day)	4–24	−sig. ↓BW: −0.65 kg (95% CI: −1.12, −0.18)	Yes	No side effects	10
							−sig. ↓BMI: −0.33 kg/m^2 (95% CI: −0.47, −0.18)
							−sig. ↓BFM: −0.94 kg (95% CI: −1.17, −0.72)
Borgeraas et al., 2018	13 (10 in Asian countries, 1 in European countries, 2 in the US)	DBRCTs, SBRCTs	737 (intervention: 369, control: 368)	Overweight or obese adults ≥18 y	Probiotic dairy products and supplements (10^9–10^11 CFU/day)	3–12	−sig. ↓BW: −0.6 kg (95% CI: −1.19, −0.01)	Yes	No side effects	11
							−sig. ↓BMI: −0.27 kg/m^2 (95% CI: −0.45, −0.08)
Dror et al., 2017	15 (7 in Asian countries, 4 in European countries, 2 in Canada, 2 in the US)	RCTs	921 (intervention: 468, control: 453)	Normal or obese or overweight adults ≥18 y	Different species of probiotic dairy and supplements (10^7–10^8 CFU/day)	8–12	−sig. ↓BW: −0.43 kg (95% CI: −0.67, −0.2)	Yes	No side effects	9
							−sig. ↓BMI: −0.43 kg/m^2 (95% CI: −0.54, −0.33)
Lavekar et al., 2017	3 (2 in European countries, 1 in Asian countries)	DBRCTs	157 (intervention: 79, control: 78)	Adults with nonalcoholic fatty liver disease	Multiple and single probiotic species (varied amounts)	12–24	−sig. ↓BMI: −1.45 kg/m^2 (95% CI: −3.06, 0.16)	Yes	No serious side effects	6
Zhang et al., 2016	25 (UN countries)	DBRCTs, RCTs	1931 (intervention: 977, control: 954)	Adults ≥18 y, both sexes	Multiple and single species of probiotic supplements (varied amounts)	3–24	−sig. ↓BW: −0.59 kg (95% CI: −0.87, −0.30)	Yes	No side effects	10
							−sig. ↓BMI: −0.49 kg/m^2 (95% CI: −0.74, −0.24)
Gao et al., 2016	6 (4 in Asian countries, 2 in European countries)	RCTs	205 (intervention: 115, control: 90)	Adults with nonalcoholic fatty liver disease, both sexes	Multiple and single species of probiotic sources (NA)	12–24	No significant effect on BMI	Yes	Few side effects	10
Sun et al., 2015	5 (1 in Korea, 1 in Japan, 1 in Iran)	DBRCTs	NA	Obese adults ≥18 y, both sexes	Different species of probiotic capsules and probiotic fermented milk (10^7–10^10 CFU/day)	8–12	−sig. ↓BMI: −0.526 kg/m^2 (95% CI: −0.810, −0.247)	Yes	No side effects	11
							−sig ↓WC: −2.11 cm (95% CI: −3.543, −0.677)
Park et al., 2015	9 (NA)	RCTs	689 (intervention: UN, control: UN)	Obese and overweight adults ≥18 y, both sexes	Probiotic supplements and dairy products (10^6–10^10 CFU/day)	3–24	No significant effect on BW or BMI	Yes	No serious side effects	9
Ma et al., 2013	4 (1 in Hong Kong, 1 in Spain, 1 in Italy, 1 in the US)	DBRCTs	134 (intervention: 68, control: 66)	Nonalcoholic patients, both sexes	Multiple and single species of probiotic sources (NA amounts)	8–24	No significant effect on BMI	Yes	No side effects	8
Million et al., 2012	5 (UN countries)	DBRCTs	319 (intervention: 257, control: 162)	Lean and obese adults ≥18 y, both sexes	Multiple and single species of probiotic sources (10^7–10^10 CFU/day)	4–24	No significant effect on BW	Yes	Weight gain in usage of L. acidophilus, L. delbrueckii, L. plantarum	10

BMI: body mass index; WC: waist circumference; BFM: body fat mass; BW: body weight; RCTs: randomized controlled trials; DBRCTs: double blind randomized controlled trials; SBRCTs: single blind randomized controlled trials; COTs: cohort study; PCOS: polycystic ovary syndrome; CFU: colony forming units; UN: unknown; NA: not available; CI: confidence interval.