β2-1 Fructan supplementation alters host immune responses in a manner consistent with increased exposure to microbial components: results from a double-blinded, randomised, cross-over study in healthy adults

Abstract

β2-1 Fructans are purported to improve health by stimulating growth of colonic bifidobacteria, increasing host resistance to pathogens and stimulating the immune system. However, in healthy adults, the benefits of supplementation remain undefined. Adults (thirteen men, seventeen women) participated in a double-blinded, placebo-controlled, randomised, cross-over study consisting of two 28-d treatments separated by a 14-d washout period. Subjects' regular diets were supplemented with β2-1 fructan or placebo (maltodextrin) at 3 × 5 g/d. Fasting blood and 1-d faecal collections were obtained at the beginning and at the end of each phase. Blood was analysed for clinical, biochemical and immunological variables. Determinations of well-being and general health, gastrointestinal (GI) symptoms, regularity, faecal SCFA content, residual faecal β2-1 fructans and faecal bifidobacteria content were undertaken. β2-1 Fructan supplementation had no effect on blood lipid or cholesterol concentrations or on circulating lymphocyte and macrophage numbers, but significantly increased serum lipopolysaccharide, faecal SCFA, faecal bifidobacteria and indigestion. With respect to immune function, β2-1 fructan supplementation increased serum IL-4, circulating percentages of CD282 + /TLR2 + myeloid dendritic cells and ex vivo responsiveness to a toll-like receptor 2 agonist. β2-1 Fructans also decreased serum IL-10, but did not affect C-reactive protein or serum/faecal Ig concentrations. No differences in host well-being were associated with either treatment, although the self-reported incidence of GI symptoms and headaches increased during the β2-1 fructan phase. Although β2-1 fructan supplementation increased faecal bifidobacteria, this change was not directly related to any of the determined host parameters.

Short-chain fatty acids, prebiotics, synbiotics, and systemic inflammation: a systematic review and meta-analysis

“…The publication year ranged from 2004 to 2017. Twenty-nine studies (43%) were from Europe (27-55), 20 (30%) were from Asia (56-75), 16 (25%) were from America (2,(76)(77)(78)(79)(80)(81)(82)(83)(84)(85)(86)(87)(88)(89)(90), and 3 (5%) were from Australia (91)(92)(93). The majority of studies (97%) were conducted in adults ($18 y).…”

“…Of the 13 studies investigating the effect of an oligosaccharide prebiotic (29, 32, 33, 36-39, 52, 62-64, 74, 77), 9 (69%) reported a significant decrease in $1 biomarker of systemic inflammation (primarily TNF-a, IL-6, CRP, or interferon-g) compared with control. An increase in inflammation (CRP, TNF-a, and IL-6) following oligosaccharide supplementation was reported in 2 studies, both of which were crossover studies conducted in healthy populations (39,77). No change in inflammation was reported in the remaining 2 studies that used oligosaccharide prebiotics, which were conducted in populations with a gastrointestinal tract condition (Crohn disease and acute diarrhea) (29,74).…”

Infant food applications of complex carbohydrates: Structure, synthesis, and function

“…[85–88] These health effects are likely due to the promotion of select bacteria, which are known to be immunostimulatory (e.g., bifidobacteria and lactobacilli) and/or the increase in concentration of selected SCFAs, which are known to promote healthy colonic tissue and function. [84] Moreover, because the increased presence of fructans increases the amount of carbohydrates in the gut, carbohydrate metabolism will be increased relative to milk protein metabolism.…”

The challenges of control groups, placebos and blinding in clinical trials of dietary interventions

“…For example trials evaluating prebiotics (28,29) or specific nutrients (30,31) can incorporate a 225 placebo control in the form of a capsule or sachet produced to replicate the intervention in 226 appearance and taste. matched in all aspects except for the active component being investigated (32) .…”