Effect of inulin-type fructans on blood lipid profile and glucose level: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND/OBJECTIVES: This systematic review and meta-analysis was performed to assess the effects of inulin-type fructans (ITF) on human blood lipids and glucose homeostasis associated with metabolic abnormalities, including dyslipidemia, overweight or obesity, and type-2 diabetes mellitus (T2DM). SUBJECTS/METHODS: The MEDLINE, EMBASE and Cochrane Library databases were systematically searched for randomized controlled trials (RCTs) before January 2016. Human trials that investigated the effects of ITF supplementation on the lipid profile, fasting glucose and insulin were included using Review Manager 5.3. RESULTS: Twenty RCTs with 607 adult participants were included in this systematic review and meta-analysis. In the overall analysis, the supplementation of ITF reduced only the low density lipoprotein-cholesterol (LDL-c) (mean difference (MD): -0.15; 95% confidence interval (CI): -0.29, -0.02; P = 0.03) without affecting the other endpoints. Within the T2DM subgroup analysis, ITF supplementation was positively associated with a decreased fasting insulin concentration (MD: -4.01; 95% CI: -5.92, -2.09; P < 0.0001) and increased high density lipoprotein-cholesterol (HDL-c) (MD: 0.07; 95% CI: 0, 0.14; P = 0.05). Moreover, a reduced fasting glucose tendency was identified only in the T2DM subgroup (MD: -0.42; 95% CI: -0.90, 0.06; P = 0.09). There was a potential publication bias, and few trials were available for the T2DM subgroup analysis. CONCLUSIONS: In summary, the use of ITF may have benefits for LDL-c reduction across all study populations, whereas HDL-c improvement and glucose control were demonstrated only in the T2DM subgroup. Thus, additional, well-powered, long-term, randomized clinical trials are required for a definitive conclusion. Overall, ITF supplementation may provide a novel direction for improving the lipid profile and glucose metabolism.