Dietary fructo-oligosaccharides in healthy adults do not negatively affect faecal cytotoxicity: a randomised, double-blind, placebo-controlled crossover trial

Abstract

Fructo-oligosaccharides (FOS) are widely used in commercial food products. Most studies on FOS concern the health benefits, but some negative effects were recently reported concerning the faecal cytotoxicity and excretion of mucin-type oligosaccharides in combination with a Ca-restricted diet. The present study was performed to investigate whether these effects of FOS are observed in adults consuming a regular diet unrestricted in Ca. The study was a randomised, double-blind, placebo-controlled crossover trial, involving eleven healthy adults, who consumed 25 -30 g FOS or maltodextrin (control) in a random order for 2 weeks in addition to their regular diet. Stools were collected for analysis of pH and SCFA (as markers of fermentation), for the assessment of faecal water cytotoxicity, and for the analysis of alkaline phosphatase activity (as a marker of epithelial cell turnover) and O-linked oligosaccharides (to estimate the excretion of mucin-type oligosaccharides). FOS consumption significantly altered bacterial fermentation (increased percentage of acetate, decreased percentage of butyrate) and tended to decrease stool pH. Furthermore, FOS consumption resulted in a significantly higher stool frequency and in significantly more complaints of flatulence. No significant differences between the control and FOS period were observed in the mean cytotoxicity of faecal water (37·5 (SEM 6·9) % v. 18·5 (SEM 6·9) %; P¼ 0·084), in mean alkaline phosphatase activity (27·7 (SEM 2·9) v. 24·6 (SEM 3·2) U/g dry faeces; P¼0·496) or in the mean excretion of mucin-type oligosaccharides (49·9 (SEM 4·0) v. 53·5 (SEM 4·3) mg/g dry faeces; P¼0·553). We conclude that dietary FOS in a dose up to 25 -30 g/d altered the bacterial fermentation pattern but did not affect faecal cytotoxicity or the faecal concentration of mucin-type oligosaccharides in human adults consuming a regular diet.Fructo-oligosaccharides: Man: Cytotoxicity: Mucin: Alkaline phosphatase Fructo-oligosaccharides (FOS) are plant fructans that naturally occur in, for example, chicory, onions, garlic, wheat and leeks. Fructans are non-digestible carbohydrates constructed of 2-60 monomer units (referred to as the degree of polymerisation). Fructans include both short-chain FOS (degree of polymerisation 2 -7) and long-chain FOS (inulin; degree of polymerisation 2-60). The estimated mean daily intake of FOS and inulin from natural sources in a European diet is between 3·2 and 11·3 g, with peak values up to 20 g (Van Loo, 1995).FOS and inulin are widely used in commercial food products, both for their technological characteristics and for their health benefits. The health benefits of FOS and inulin can be attributed to their fermentation by the intestinal microbiota. Several studies suggest that FOS and inulin are involved in the selective stimulation of the growth of beneficial bacteria, such as bifidobacteria, in the gastrointestinal tract (reviewed by Kolida et al. 2002). Some of these studies have also shown a decrease in the number of pathogenic bacteria (Kolida et al. ...

Macronutrients and type 1 diabetes (revision number 6)

“…Eight trials determine faecal SCFA content in response to non-digestible oligosaccharide or inulin supplementation and none report an effect on overall SCFA content. Five trials report no significant effect of non-digestible oligosaccharide or inulin supplementation (3-15g/day) on individual faecal SCFA content (Alles et al, 1999;Swanson et al, 2002;Kleessen et al, 2007;Ramnani et al, 2010;Walton et al, 2010) three report an increase in the concentration or proportion of faecal acetate to higher doses of non-digestible oligosaccharide or inulin (15-30g/day) Causey et al, 2000;Scholtens et al, 2006b). None of the trials report an effect of non-digestible oligosaccharide or inulin supplementation on faecal pH.…”

“…The data on measures of faecal pH and short chain fatty acid content were insufficiently comparable to allow a meta-analysis. Nine trials supplemented subjects with fructo-oligosaccharides (doses 2.5-30g/day) (Bouhnik et al, 1996;Bouhnik et al, 1999;Tahiri et al, 2001;Tuohy et al, 2001;Swanson et al, 2002;Bouhnik et al, 2004;Bouhnik et al, 2006;Scholtens et al, 2006b). Three trials supplemented subjects with galacto-oligosaccharides (doses 8.5-15g/day) (Alles et al, 1999;Bouhnik et al, 2004), six trials supplemented subjects with inulin Causey et al, 2000;Bouhnik et al, 2004;Bouhnik et al, 2007;Kleessen et al, 2007;Ramnani et al, 2010) and one trial supplemented subjects with mannooligosaccharides derived from coffee (Walton et al, 2010).…”

“…Three trials supplemented subjects with galacto-oligosaccharide (doses 10-15g/day) (Ito et al, 1990;Alles et al, 1999;; three trials supplemented subjects with inulin (doses 15-20g/day) Causey et al, 2000;Den Hond et al, 2000); and four trials supplemented subjects with fructo-oligosaccharide (doses 10-30g/day) (Bouhnik et al, 1996;Tahiri et al, 2001;Scholtens et al, 2006b). All trials compared supplemented groups to either a sugar or maltodextrin control.…”

“…Fifteen randomised controlled trials in adults were identified that presented evidence on non-digestible oligosaccharide or inulin supplementation in relation to faecal pH or SCFA content (Bouhnik et al, 1996;Bouhnik et al, 1999;Alles et al, 1999;Causey et al, 2000;Den Hond et al, 2000;Tuohy et al, 2001;Tahiri et al, 2001;Bouhnik et al, 2004;Bouhnik et al, 2006;Scholtens et al, 2006b;Bouhnik et al, 2007;Kleessen et al, 2007;Ramnani et al, 2010;Walton et al, 2010). No further trials were identified in the update search (Colo-rectal health review p100).…”

“…Nine randomised controlled trials in adults were identified that presented evidence on non-digestible oligosaccharide or inulin supplementation in relation to faecal weight, of which eight were included in the meta-analyses (Ito et al, 1990;Bouhnik et al, 1996;Alles et al, 1999;Causey et al, 2000;Den Hond et al, 2000;Tahiri et al, 2001;Scholtens et al, 2006b). There was no indication that doses of less than 10g/day had any effect on faecal wet weight, so only data from doses of 10g/day or more were used.…”