Objective To systematically review the effect of oral intake of bacterial probiotics on 15 variables related to obesity, diabetes and non-alcoholic fatty liver disease.
Design Systematic review and meta-analysis.
Data sources Medline, EMBASE and COCHRANE from 1990 to June 2018.
Eligibility criteria Randomised controlled trials (≥14 days) excluding hypercholesterolaemia, alcoholic liver disease, polycystic ovary syndrome and children <3 years.
Results One hundred and five articles met inclusion criteria, representing 6826 subjects. In overweight but not obese subjects, probiotics induced improvements in: body weight (k=25 trials, d=−0.94 kg mean difference, 95% CI −1.17 to −0.70, I²=0.0%), body mass index (k=32, d=−0.55 kg/m², 95% CI −0.86 to −0.23, I²=91.9%), waist circumference (k=13, d=−1.31 cm, 95% CI −1.79 to −0.83, I²=14.5%), body fat mass (k=11, d=−0.96 kg, 95% CI −1.21 to −0.71, I²=0.0%) and visceral adipose tissue mass (k=5, d=−6.30 cm², 95% CI −9.05 to −3.56, I²=0.0%). In type 2 diabetics, probiotics reduced fasting glucose (k=19, d=−0.66 mmol/L, 95% CI −1.00 to −0.31, I²=27.7%), glycated haemoglobin (k=13, d=−0.28 pp, 95% CI −0.46 to −0.11, I²=54.1%), insulin (k=13, d=−1.66 mU/L, 95% CI −2.70 to −0.61, I²=37.8%) and homeostatic model of insulin resistance (k=10, d=−1.05 pp, 95% CI −1.48 to −0.61, I²=18.2%). In subjects with fatty liver diseases, probiotics reduced alanine (k=12, d=−10.2 U/L, 95% CI −14.3 to −6.0, I²=93.50%) and aspartate aminotransferases (k=10, d=−9.9 U/L, 95% CI −14.1 to -5.8, I²=96.1%). These improvements were mostly observed with bifidobacteria (Bifidobacterium breve, B. longum), Streptococcus salivarius subsp. thermophilus and lactobacilli (Lactobacillus acidophilus, L. casei, L. delbrueckii) containing mixtures and influenced by trials conducted in one country.
Conclusions The intake of probiotics resulted in minor but consistent improvements in several metabolic risk factors in subjects with metabolic diseases.
Trial registration number CRD42016033273.
- non-alcoholic fatty liver disease
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HK and BG contributed equally.
Contributors Study concept and design: HK, BG, JS, SR, KC. Systematic literature review: BG, HK, JS, MMS, JMF. Data extraction: BG, HK, JS, MMS, JMF. Concept and conduct of statistical analysis: BG. Interpretation of data: HK, BG, MMS, SR, JS, KC. Drafting of the manuscript: HK, BG. Critical revision HK, BG, MMS, JMF, SR, JS, KC. All authors approved the final version to be published and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Funding Danone Nutricia Research, Palaiseau, France. The work of BGStats Consulting was funded by Danone Research, Palaiseau, France. Danone Research supported collaborative work of the Institute of Cardiometabolism and Nutrition. JS received consultancy fee from Danone Research.
Competing interests HK and JMF are employees of Danone Nutricia Research; BG received funding from Danone Research; JS received consultancy fees from Danone Research, is presently member of the Scientific Advisory Board of Actial SRL and acted as expert for Actial in a court hearing ; KC, MMS and SR have a collaborative agreement with Danone Research.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Authors have included all available data in the research through supplementary figures and tables.
Patient consent for publication Not required.
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