Absolute and relative bacterial abundance and bacterial diversity on pooled faecal samples after following a habitual diet for 5 days and low FODMAP and typical Australian diets for 17–21 days in cross-over trial (n=33)
| Measure | Bacteria | Australian diet | Low FODMAP diet | p Value | Habitual diet |
|---|---|---|---|---|---|
| Absolute abundance (Log10 copies of 16S rRNA gene/g) | Total bacteria | 9.83 (9.72–9.93) | 9.63* (9.53–9.73) | <0.001 | 9.85 (9.73–9.96) |
| Clostridium cluster IV | 8.33 (8.15–8.52) | 8.05* (7.88–8.23) | <0.001 | 8.39 (8.23–8.56) | |
| Faecalibacterium prausnitzii | 7.72 (7.49–7.95) | 7.45* (7.25–7.65) | <0.001 | 7.84 (7.67–8.01) | |
| Clostridium cluster XIVa | 9.05* (8.93–9.16) | 8.03 (7.91–8.15) | <0.001 | 8.22 (8.09–8.36) | |
| Roseburia | 7.72 (7.59–7.85) | 7.49 (7.34–7.63) | <0.001 | 7.62 (7.45–7.79) | |
| Lactobacilli | 6.35 (6.20–6.50) | 6.08 (5.91–6.24) | 0.003 | 6.21 (6.00–6.42) | |
| Bifidobacteria | 7.71 (7.53–7.88) | 7.30* (7.11–7.50) | <0.001 | 7.70 (7.48–7.91) | |
| Akkermansia muciniphila† | 5.46* (4.88–6.04) | 4.29 (3.58–4.99) | <0.001 | 4.29 (3.67–4.92) | |
| Ruminococcus gnavus | 7.26 (7.14–7.37) | 7.10 (6.96–7.25) | 0.002 | 7.16 (7.04–7.28) | |
| Ruminococcus torques | 6.08 (5.85–6.31) | 6.23 (6.07–6.39) | 0.140 | 6.20 (5.97–6.44) | |
| Relative abundance (percentage of total bacteria) | Clostridium cluster IV | 4.00 (3.21–4.71) | 3.32 (2.70–3.94) | 0.108 | 3.99 (3.39–4.60) |
| F. prausnitzii | 1.11 (0.82–1.40) | 0.95 (0.69–1.22) | 0.108 | 1.29 (0.92–1.66) | |
| Clostridium cluster XIVa | 18.1* (15.4–20.8) | 2.72 (2.33–3.12) | <0.001 | 2.63 (2.26–3.01) | |
| Roseburia | 0.85 (0.585–1.11) | 0.82 (0.68–0.96) | 0.153 | 0.79 (0.58–1.00) | |
| Lactobacilli | 0.05 (0.03–0.06) | 0.04 (0.03–0.05) | 0.634 | 0.06 (0.01–0.11) | |
| Bifidobacteria | 1.33 (0.74–1.92) | 0.87 (0.47–1.27) | 0.028 | 1.48 (0.79–2.18) | |
| A. muciniphila† | 0.10* (0.03–0.16) | 0.02 (0.01–0.03) | <0.001 | 0.01 (0–0.02) | |
| R. gnavus | 0.37 (0.23–0.50) | 0.41 (0.27–0.53) | 0.480 | 0.27 (0.19–0.36) | |
| R. torques | 0.04 (0.02–0.06) | 0.06 (0.04–0.09) | 0.001 | 0.05 (0.02–0.08) | |
| Diversity (Shannon index) | Clostridium cluster XIV | 1.47 (1.39–1.55) | 1.79‡ (1.70–1.89) | <0.001 | 1.60 (1.46–1.73) |
Interventional diets were analysed by Wilcoxon matched-pairs signed rank test. Statistically significant differences are shown in bold and based upon p≤0.05 for bacterial diversity, p≤0.005 for absolute and p≤0.006 for relative bacterial abundance after Bonferroni correction. Differences between habitual diet and interventional diets are indicated with an asterisk.
*p<0.001 compared with habitual diet; Wilcoxon matched-pairs signed rank test.†Due to difficulties in microbial analysis for A. muciniphila, three IBS subjects could not be included; n=30.
‡p<0.05 compared with habitual diet; pairwise permanova test.
FODMAP, Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols.