50 Evaluating influences of fructans on cytokine and immunoglobulin production in a human clinical trial

A double-blind, placebo-controlled, randomized crossover clinical trial involving 30 healthy adults was conducted to examine the impact of fructans on both the gut microbiota and immune system. Along with their regular diet, trial participants consumed either an oligofructose-enriched inulin supplement as the test diet or food grade maltodextrin as the control diet for a 28day period, with a minimum 2week washout period before cross-over. The trial supplements were coded as “A” or “B”, and will remain coded until the completion of all analyses. Serum immunoglobulin concentrations were quantified by Luminex multiplexing technology. IgM was significantly higher after 28days of supplement A consumption (821.3ng/mL±138.3) than after supplement B consumption (485.8ng/mL±66.5) (P=0.0118). IgA was also significantly higher (P=0.0092) after supplement A consumption (1967.3ng/mL±374.4) than after supplement B consumption (911.7ng/mL±138.2). Active transforming growth factor-beta (TGF-β) concentration was measured in plasma and serum cytokine concentrations were quantified by Enzyme-linked immunosorbent assay (ELISA). Levels of active TGF-β were 5.4pg/mL±2.1 after consumption of supplement B, in comparison to 3.4pg/mL±1.5 after supplement A consumption, although this difference was not statistically significant. IL-10 concentrations were significantly lower (P=0.0172) after supplement B consumption (41.2pg/mL±29.0) than after supplement A consumption (79.8pg/mL±42.1). Granulocyte colony-stimulating factor (G-CSF) levels were also significantly lower (P=0.0265) after supplement B consumption (5.4pg/mL±2.5) than levels after supplement A consumption (14.4pg/mL±3.6). No differences were observed between subjects consuming supplement A and B in Interleukin-8 (IL-8) and IL-1Ra concentrations. Analysis of cytokine profiles will provide insight into the extent of the potential effects of dietary fructans on the immune system mediated through the gut microbiota.