The effects of inulin-type fructans on cardiovascular disease risk factors: systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Inulin-type fructans (ITF) are the leading prebiotics in the market. Available evidence provides conflicting results regarding the beneficial effects of ITF on cardiovascular disease risk factors. OBJECTIVES: This study aimed to evaluate the effects of ITF supplementation on cardiovascular disease risk factors in adults. METHODS: We searched MEDLINE, EMBASE, Emcare, AMED, CINAHL, and the Cochrane Library databases from inception through May 15, 2022. Eligible randomized controlled trials (RCTs) administered ITF or placebo (for example, control, foods, diets) to adults for ≥2 weeks and reported one or more of the following: low, very-low, or high-density lipoprotein cholesterol (LDL-C, VLDL-C, HDL-C); total cholesterol; apolipoprotein A1 or B; triglycerides; fasting blood glucose; body mass index; body weight; waist circumference; waist-to-hip ratio; systolic or diastolic blood pressure; or hemoglobin A1c. Two reviewers independently and in duplicate screened studies, extracted data, and assessed risk of bias. We pooled data using random-effects model, and assessed the certainty of evidence (CoE) using the Grading of Recommendations, Assessment, Development and Evaluation approach. RESULTS: We identified 1767 studies and included 55 RCTs with 2518 participants in meta-analyses. The pooled estimate showed that ITF supplementation reduced LDL-C [mean difference (MD) -0.14 mmol/L, 95% confidence interval (95% CI: -0.24, -0.05), 38 RCTs, 1879 participants, very low CoE], triglycerides (MD -0.06 mmol/L, 95% CI: -0.12, -0.01, 40 RCTs, 1732 participants, low CoE), and body weight (MD -0.97 kg, 95% CI: -1.28, -0.66, 36 RCTs, 1672 participants, low CoE) but little to no significant effect on other cardiovascular disease risk factors. The effects were larger when study duration was ≥6 weeks and in pre-obese and obese participants. CONCLUSION: ITF may reduce low-density lipoprotein, triglycerides, and body weight. However, due to low to very low CoE, further well-designed and executed trials are needed to confirm these effects. PROSPERO REGISTRATION NUMBER: CRD42019136745.

Assessment of reporting quality of randomized controlled trials investigating the effects of inulin-type fructans supplementation on cardiovascular disease risk factors: A systematic survey.

BACKGROUND: Transparent and detailed reporting of randomized controlled trials (RCTs) is essential to judge its validity and generalizability. We assessed the reporting quality of RCTs examining the effects of inulin-type fructans supplementation on cardiovascular risk factors, before and after the publication of the Consolidated Standards of Reporting Trials (CONSORT) in 2010. METHODS: We searched MEDLINE, EMBASE, Emcare, AMED, the Cochrane Library, and CINAHL from inception to May 15, 2022, including the reference lists of selected RCTs. We screened titles and abstracts and extracted the data independently and in duplicate. We included RCTs that investigated the effects of inulin-type fructans on cardiovascular disease risk factors (e.g., low-density lipoprotein cholesterol, triglycerides, fasting blood glucose) in adults (18 years or older). The primary outcomes of this study were: the overall reporting quality of RCTs (defined as the total number of items [0 to 36] present from the CONSORT checklist) published before and after CONSORT; and the study characteristics (e.g., sample size, significance of primary outcome) predictive of the CONSORT score. The secondary outcome was the reporting of each specific item of the CONSORT checklist during pre- and post-CONSORT periods. The mean difference in the total number of reported items in studies published before and after CONSORT were compared using a t-test and Poisson regression to explore the factors associated with overall reporting quality of RCTs. We used Fisher's exact test to compare the adherence to each of the 36 items during pre- and post-CONSORT periods. RESULTS: We identified 1,767 citations from our systematic search, of which 55 were eligible. There was a significant increase in the reporting of CONSORT items (mean difference 8.5, 95% confidence interval [CI] 5.24 to 11.71) between studies published before and after publication of CONSORT. The sole variable that was predictive of better reporting quality of RCTs was whether the study was published before or after CONSORT (incidence rate ratio 1.67, 95% CI 1.40 to 2.02). Completeness of reporting of RCTs only improved in 15 out of 36 items (41.6%) after the publication of CONSORT. CONCLUSION: The completeness of reporting in RCTs investigating inulin-type fructans supplementation on cardiovascular disease risk factors remains inadequate after the publication of CONSORT. Greater adherence to CONSORT by authors and enforcement of CONSORT by journals may improve the quality of reporting among RCTs.