The effect of probiotics, prebiotics or synbiotics on metabolic outcomes in individuals with diabetes: a systematic review and meta-analysis

Abstract

Aims/hypothesis The aim was to conduct a systematic review and meta-analysis of randomised controlled clinical trials assessing the effect of probiotic, prebiotic or synbiotic supplementation on gut microbiota and glucose control and lipid levels in individuals with diabetes. Methods MEDLINE, EMBASE and the Cochrane Library were searched. The eligibility criteria for the studies was involvement of participants with a diagnosis of type 1 or type 2 diabetes. Metabolic outcomes (glucose control, insulinaemia, and lipid profile) of any probiotic, prebiotic or synbiotic supplementation related to modification of gut microbiota (prebiotics, probiotics and synbiotics) were analysed. We provided a narrative synthesis and meta-analysis of the findings on metabolic outcomes from the studies. Metabolic outcomes were extracted post-intervention and expressed as mean differences (MDs) and 95% CIs between treatment and comparator groups. We pooled the results using a random-effects meta-analysis. The meta-analysis was conducted using Review Manager (RevMan) software. Results After the removal of duplicates and ineligible studies, 5219 studies were retained for review of titles and abstracts. The number of articles was reduced to 130 by review, for which the full-text articles were obtained and reassessed, 38 of which were included in the final meta-analysis. Overall, the use of prebiotics, probiotics or synbiotics reduced HbA 1c levels, but did not reach the threshold for significance (−2.17 mmol/mol, 95% CI −4.37, 0.03; p = 0.05, [−0.20%, 95% CI −0.40 to 0.00; p = 0.05, I 2 = 66%]) and had no effect on LDL-cholesterol levels (−0.05 mmol/l; 95% CI −0.14, 0.05, p = 0.35, I 2 = 37%). However, their consumption decreased levels of fasting blood glucose (−0.58 mmol/l; 95% CI −0.86, −0.30; p < 0.01, I 2 = 60%), total cholesterol (−0.14 mmol/l; 95% CI −0.26, −0.02, p = 0.02, I 2 = 39%), triacylglycerols (−0.11 mmol/l; 95% CI −0.20, −0.02, p = 0.01, I 2 = 21%) and insulinaemia (−10.51 pmol/l; 95% CI −16.68,−4.33, p < 0.01, I 2 = 74%), and increased HDL-cholesterol levels (0.04 mmol/l; 95% CI 0.01, 0.07, p < 0.01, I 2 = 24%).

Nutrition in Patients with Type 2 Diabetes: Present Knowledge and Remaining Challenges

“…Clinical data are specifically referred to gestational diabetes [ 132 , 133 ]; in these women four high-quality RCTs (288 participants) showed that treatment was associated with a significant reduction in insulin resistance (HOMA-IR: −0.69%; 95% CI −1.24, −0.14, p = 0.01), not in fasting glucose (−0.13 mmol/L; 95% CI −0.32, 0.06, p = 0.18) or LDL-cholesterol (−0.16 mmol/L; 95% CI −0.45, 0.13, p = 0.67) [ 133 ]. In the general diabetes population, the most recent review identified 38 studies totalling 2086 participants fitting pre-defined criteria to be included in a meta-analysis [ 134 ]. Overall, the use of prebiotics, probiotics or synbiotics reduced fasting glucose (−0.58 mmol/L; 95% CI −0.86, −0.30; p < 0.01), total cholesterol (−0.14 mmol/L; 95% CI −0.26, −0.02, p = 0.02) and triglyceride levels (−0.11 mmol/L; 95% CI −0.20, −0.02, p = 0.01) and increased HDL-cholesterol (0.04 mmol/L; 95% CI 0.01, 0.07, p < 0.01), but failed to reach the significance threshold in HbA1c (−2.17 mmol/mol; 95% CI, −4.37 to 0.03; p = 0.05) and had no effect on LDL-cholesterol [ 134 ].…”

“…In the general diabetes population, the most recent review identified 38 studies totalling 2086 participants fitting pre-defined criteria to be included in a meta-analysis [ 134 ]. Overall, the use of prebiotics, probiotics or synbiotics reduced fasting glucose (−0.58 mmol/L; 95% CI −0.86, −0.30; p < 0.01), total cholesterol (−0.14 mmol/L; 95% CI −0.26, −0.02, p = 0.02) and triglyceride levels (−0.11 mmol/L; 95% CI −0.20, −0.02, p = 0.01) and increased HDL-cholesterol (0.04 mmol/L; 95% CI 0.01, 0.07, p < 0.01), but failed to reach the significance threshold in HbA1c (−2.17 mmol/mol; 95% CI, −4.37 to 0.03; p = 0.05) and had no effect on LDL-cholesterol [ 134 ].…”

Microbial regulation of enteroendocrine cells

“…The recent meta-analysis again emphasizes that supplementing probiotics, prebiotics, and synbiotics in the diet is beneficial to a small extent and may complement the drug regimens, thus increasing overall improvement in metabolic status. 148…”

Holistic perspective of the role of gut microbes in diabetes mellitus and its management

“…Another meta-analysis showed similar result with reduction in HbA1c% (WMD = - 0.24, 95%CI: - 0.44 to - 0.04, P = 0.02), fasting blood glucose (WMD = - 0.44 mmol/L, 95%CI: - 0.74 to - 0.15, P = 0.003)[ 113 , 114 ]. A meta-analysis study done in 2021 with probiotics, prebiotics or synbiotics on type 2 DM also showed significant improvement in glucose and other metabolic parameters[ 115 ]. Prebiotic inulin improves glycemic control in young adults with type 1 DM[ 116 ].…”