Effects of dietary inulin on serum lipids, blood glucose and the gastrointestinal environment in hypercholesterolemic men

Abstract

Inulin is a complex carbohydrate that belongs to a class of compounds known as fructans. Inulin has been consumed in plant sources by mankind for centuries, and is most concentrated in chicory, Jerusalem artichoke, garlic, leek and onion. It can be extracted from purified concentrated sources such as chicory root, and used to enhance the technological and nutritional properties of foods. Inulin is thought to share many of the properties of soluble dietary fibers, such as the ability to lower blood lipids and stabilize blood glucose. Additionally, inulin has been shown to enhance the growth of bifidobacteria and lactobacilli and enhance the gut environment. The objective of this study was to examine the effect of a commercially available inulin from chicory root (degree of polymerization (DP) ranging between 2 and 60, modal DP=9) in men with hypercholesterolemia on serum parameters and fecal composition. The study was a randomized, double blind, crossover design with no washout period. Twelve men were randomly assigned to two controlled diets that differed only in that the control diet contained one pint of vanilla ice cream made with sucrose while the inulin containing diet was supplemented with one pint of vanilla ice cream made with 20 grams of inulin. Subjects consumed each controlled diet for three weeks. Daily intake of 20 g of inulin significantly reduced serum triglycerides by 40 mg/dL (p=0.05). A trend toward a reduction in serum cholesterol was observed. Trends toward short chain fatty acid (SCFA) profile changes were observed after inulin administration. Transit time did not differ significantly between treatments. These data suggest that dietary inulin supplementation may improve blood lipid profiles and alters the colonic environment in a manner that may be beneficial. Because inulin is easily incorporated into an acceptable food like low-fat vanilla ice cream, it shows promise as a functional ingredient in many processed foods.