The analysis looked at the potential cardiovascular benefits of consuming inulin, oligofructose and fructo-oligosaccharides (FOS), known as inulin-type fructans (ITF).
“To the best of our knowledge, the present systematic review and meta-analysis is the first study to include trials performed with different characteristics of participants (normal healthy, dyslipidemia, overweight or obese, and T2DM),” wrote the authors from the Southern Medical University in Guangzhou and the Shandong University of Traditional Chinese Medicine in the European Journal of Clinical Nutrition.
“The main finding of this meta-analysis is that ITF supplementation may lower LDL-cholesterol across all study populations.”
While the mechanism by which the inulin-type fructans may help manage lipid levels is unclear, the authors noted that one possible pathway may be via decreasing cholesterol absorption in the intestine. “Inulin is a soluble and viscous compound that increases the thickness of the unstirred layer of the small intestine, which thus inhibits the absorption of cholesterol,” they wrote.
Another possible mechanism is by modifying the composition of the gut microflora, which may increase the production of short chain fatty acids like butyrate that has been reported to inhibit the synthesis of cholesterol in the liver.
“The only trial that assessed gut microbiota composition in the meta-analysis indicated that treatment with ITF prebiotics (inulin/oligofructose 50/50 mix) led to an increase in Bifidobacterium and Feacalibacterium prausnitzii, which are negatively correlated with the serum lipopolysaccharide (pro-inflammatory component) levels,” they wrote.
The China-based scientists pooled data from 20 randomized controlled trials including 607 people for their analysis. The results showed that ITF supplementation was associated with significant reductions in LDL-cholesterol across all the different population groups.
ITF supplementation was also associated with decreased insulin levels and increased HDL cholesterol levels for type 2 diabetics only, they added.
The meta-analysis found that dietary ITF supplementation may reduce LDL-cholesterol levels by 0.15 mmol/L, which is about 5% of the recommended LDL-cholesterol level of less than 3.37 mmol/L for healthy adults.
The BMJ Clinical Evidence: Estimating Cardiac Vascular Disease states that an LDL reduction of 20% can reduce the cardiovascular risk by 25% over a five-year period.
“Thus, ITF supplementation, in combination with proven dietary strategies for LDL-Cholesterol reductions (for example the portfolio diet), may be a useful preventive measure for Cardiac Vascular Disease via its reduction in the LDL- Cholesterol concentration.”
Leading inulin suppliers Beneo, Cosucra, and Sensus recently submitted a citizen petition to the FDA requesting the addition of chicory inulin to the list of dietary fiber.
The FDA recently outlined a new definition for dietary fiber, which defines dietary fiber as either naturally occurring fibers that are intrinsic and intact in plants, or as isolated or synthetic fibers that have demonstrated a beneficial physiological effect.
The Citizen Petition requests the addition of chicory inulin, encompassing all chicory inulin-type fructans, to be added to the list of dietary fiber accepted in the US. The rationale for this submission is to display the totality of pertinent data that convincingly shows the beneficial physiological effects of chicory root inulin.
Source: European Journal of Clinical Nutrition
Published online ahead of print, doi: 10.1038/ejcn.2016.156
“Effect of inulin-type fructans on blood lipid profile and glucose level: a systematic review and meta-analysis of randomized controlled trials”
Authors: F Liu et al