Xylooligosaccharides help balance gut microflora in healthy adults, study shows
Highlights
- Randomized, double-blind, placebo-controlled trial
- Supplementation: 1-2 g/day xylooligosaccharides (XOS) for 8 weeks
- Compared to placebo, XOS significantly increases Bifidobacteria in the colon and helps balance gut flora in a dose-dependent manner
- XOS is well tolerated without gastrointestinal side effects
Summary
This double-blind, randomized, placebo-controlled study was designed to evaluate the effects and tolerance of xylooligosaccharides (XOS) on the composition of human colonic microbiota, pH and short chain fatty acids (SCFA) in healthy adults.
For this study, researchers enrolled 32 healthy men and women, aged 21 to 49 years. Participants were randomly assigned to receive one of three supplements: placebo, 1 g/day XOS or 2 g/day XOS for 8 weeks after a 2-week run-in and followed by a 2-week washout phase. The dosing was twice daily. Stool samples were collected at baseline, week 4, week 8, and 2 weeks after intervention ended. Stool samples were cultured for total bacterial flora, pH and short-chain fatty acid (SCFA) analyses. Pyrosequencing technology (16S rRNA gene-based) was used to assess bacterial diversity with the ability to detect both abundant and rare bacteria in the gut microbiome. Tolerance was evaluated by a daily chart of digestive symptoms graded from 0 (no symptoms) to 3 (severe symptoms). Frequency and consistency of stools were also noted with diarrhea determined as one or more liquid stools or more than 3 stools per day.
Compared to the placebo, the amount of Bifidobacteria significantly increased in both XOS groups with the high-dose group showing significantly (P<.05) greater increases than the low-dose group. Total anaerobic counts and Bacteroides fragilis group counts were also significantly higher in the high-dose XOS group. No significant differences in the amounts of Lactobacillus, Enterobacteriaceae and Clostridium were reported between the three groups. XOS intervention had no significant effect on stool pH, SCFA or lactic acid. Pyrosequencing showed no notable shifts in bacterial diversity. XOS was well tolerated without significant gastrointestinal side effects (e.g., excess flatus, intestinal gurgling, bloating, abdominal pain, or diarrhea).
These findings indicate that supplementing with 1-2 g/day XOS for 8 weeks significantly increases Bifidobacteria in the colon, helps balance gut flora in a dose-dependent manner, and is well tolerated without gastrointestinal side effects in healthy adults.
