Benefits
Fermented by bifidobacteria in laboratory cultures
In pH-controlled batch cultures seeded with stool from eight healthy adults, the alpha-glucan oligosaccharide raised bifidobacteria counts compared with the control and increased acetate and propionate. That was a test-tube experiment rather than people taking the ingredient, and the one human trial that measured stool bacteria found no significant genus-level shift.
Gentle fermentation profile
Short-chain fatty acid production was measured in laboratory fermentation, not in people, and no trial has set out to measure digestive comfort, stool frequency or bloating as an outcome. In batch culture the oligosaccharide produced less total gas, and produced it more gradually, than inulin. In the one oral human study, bloating was recorded as an adverse event in one participant taking the supplement and one taking placebo, and both left the study.
Mechanism of action
Selective fermentation
In laboratory fermentation of human stool samples, bifidobacteria used the oligosaccharide preferentially and acetate and propionate rose. Whether the same happens in the gut of a person taking it has not been shown.
Competitive support
Favoring bifidobacteria is proposed to leave less room for less desirable species, but that has not been shown. Even in the batch-culture experiment, the other bacterial groups measured were either unchanged or, in the case of the Bacteroides-Prevotella group, increased, and no study in people has tested the idea.
Clinical trials
In vitro fermentation of the commercial alpha-glucan oligosaccharide (BioEcolians, Solabia) in anaerobic batch cultures seeded with stool from four lean and four obese healthy adults, with inulin as the prebiotic comparator. (Sarbini et al. 2013, British Journal of Nutrition)
Human faecal microbiota (in vitro).
Bifidobacteria increased relative to the control; the Bacteroides-Prevotella group rose and Faecalibacterium prausnitzii fell from baseline on both this oligosaccharide and the inulin comparator. Acetate and propionate increased, and total gas production was lower and more gradual than with inulin. Nobody consumed the ingredient in this experiment.
Double-blind, placebo-controlled randomized trial of 8 g/day gluco-oligosaccharide (BioEcolians, Solabia) plus Bifidobacterium longum bv. infantis CCUG 52486 for eight weeks, with seasonal influenza vaccination at week 4. Reported across several papers from one trial, NCT01066377. (Przemska-Kosicka et al. 2016, Immunity & Ageing; Enani et al. 2018, Clinical Nutrition; Przemska-Kosicka et al. 2018, Frontiers in Immunology)
58 young (18-35 y) and 54 older (60-85 y) healthy adults completed the study.
The combination did not improve antibody titres, seroprotection or seroconversion to any of the three vaccine strains, and did not alter B cell, T cell or natural killer cell responses. No significant genus-level change in the stool microbiota was observed. In older participants, seroconversion to the Brisbane strain and the vaccine-specific IgG response trended lower on the supplement than on placebo, but the older participants assigned to the supplement happened to begin the study with significantly more immune ageing and more cytomegalovirus seropositivity than those assigned to placebo, so that trend cannot be read as an effect of the supplement. Because the oligosaccharide was given together with a probiotic, its own contribution cannot be separated out.