Table 2.
Cutoff thresholds of dietary fiber on gut microbiota in intervention trials.
| Author (Year) Region |
Participants N | F:M a Mean Age (Years) |
RCT Design |
Dietary Fiber |
Type of Fiber |
Administrated Dosage (g/day) |
Duration of Intervention |
Changes in Gut Microbiota b | Cutoff Threshold (g/day) |
|---|---|---|---|---|---|---|---|---|
| Kolida, S. [116] (2007) UK |
30 | 15:15 26.5 ± 3.1 |
double-blind crossover |
Inulin | NSP | 0 g 5 g 8 g |
2-week intervention 1-week washout |
↑: Bifidobacteria * Depending on initial abundance |
NO |
| Reimer, R. A. [117] (2020) Canada |
50 | 28:22 around 31 |
double-blind crossover |
Inulin-type fructans (ITF) | NSP | 0 g or 7 g (n = 25) 0 g or 3 g (n = 25) |
4-week intervention 4-week washout |
↔: α-diversity (Shannon index) ↔: β-diversity (Bray–Curtis distance) ↑: Bifidobacterium, Cellulomonas, Nesterenkonia, Brevibacterium ↓: Lachnospira, Oscillospira ↔: Fecal SCFAs |
7 g for Bifidobacterium, Cellulomonas, Nesterenkonia, Brevibacterium, Lachnospira, Oscillospira |
| Calame, W. [105] (2008) Netherlands |
48 | -- 30.9 ± 12.8 |
double-blind | Gum arabic | NSP | 0 g (placebo-control, n = 8) 5 g (n = 8) 10 g (n = 8) 20 g (n = 8) 40 g (n = 8) 10 g inulin (positive control, n = 8) |
4-week intervention |
↑: Bifidobacteria, lactobacilli, bacteroides | 10 g for bifidobacteria, lactobacilli, bacteroides |
| Deehan, E. C. [118] (2020) Canada |
40 | 20:20 28.4 ± 8.1 |
double-blind | RS4 | RS | Placebo (n = 10) Maize RS4 (n = 10) Potato RS4 (n = 10) Tapioca RS4 (n = 10) All 10 g for 1 week →20 g for 1 week →35 g for 1 week →50 g for 1 week |
4-week intervention |
In maize group: ↓: α-diversity (Pielou and Shannon index) ↕: β-diversity (Bray-Curtis) ↑: Bifidobacterium ↑: Eubacterium rectale, Oscillibacter, Anaeromassilibacillus, Ruminococcus ↓: Agathobaculum butyriciproducens, Adlercreutzia equolifaciens ↑: Fecal butyrate In tapioca group: ↓: α-diversity (Pielou and Shannon index) ↕: β-diversity (Bray-Curtis) ↑: Bifidobacterium ↑: Parabacteroides distasonis, Faecalibacterium, Eisenbergiella ↓: Eubacterium hallii and Clostridium viride ↑: Fecal propionate *No effect of potato RS4 detected |
In maize group: 20 g for α-diversity, β-diversity, Eubacterium rectale, Oscillibacter, Anaeromassilibacillus, Ruminococcus; 35 g for fecal butyrate; In tapioca group: 35 g for α-diversity, β-diversity, fecal propionate |
| Bouhnik, Y. [119] (1999) France |
40 | 22:18 29.6 |
Short-chain fructo-oligosaccharides (SC-FOS) |
ROS | 0 g (n = 8) 2.5 g (n = 8) 5 g (n = 8) 10 g (n = 8) 20 g (n = 8) |
7-day intervention |
↑: Bifidobacteria | 5 g for bifidobacteria | |
| Bouhnik, Y. [120] (2006) France |
40 | 22:18 29 ± 1.3 |
Short-chain fructo-oligosaccharides (SC-FOS) |
ROS | 0 g (n = 8) 2.5 g (n = 8) 5 g (n = 8) 7.5 g (n = 8) 10 g (n = 8) |
7-day intervention |
↑: Bifidobacteria (linear correlation) ↑: Total anaerobes |
10 g for total anaerobes | |
| Tandon, D. [121] (2019) India |
69 | 35:34 around 30 |
double-blind | Fructo-oligosaccharides (FOS) |
ROS | 0 g (n = 17) 2.5 g (n = 16) 5 g (n = 18) 10 g (n = 18) |
90-day intervention |
↑: α-diversity (Chao) ↑: Bifidobacterium, Lactobacillus, Faecalibacterium, Ruminococcus, Sutterella, Oscillospira *Reversal impact of prebiotics postdiscontinuation *Inconsistent results of analyses performed on data at two distinct levels of taxonomy (OTUs or genus) |
10 g for α-diversity, Bifidobacterium, Lactobacillus, Faecalibacterium, Ruminococcus, Sutterella, Oscillospira |
| Maki, K. C. [122] (2012) The US |
55 | -- 53.1 ± 12.6 |
double-blind crossover |
Arabinoxylan-oligosaccharide (AXOS) |
ROS | 0 g 2.2 g 4.8 g |
3-week intervention 2-week washout |
↑: Bifidobacterium spp. | 4.8 g for Bifidobacterium spp. |
| François, I. E. [123] (2012) Belgium |
57 | 27:30 42 ± 17 |
double-blind crossover |
Arabinoxylan oligosaccharides (AXOS) | ROS | 0 g 2.4 g 8 g |
3-week intervention 2-week washout |
↑: Bifidobacteria ↑: Fecal SCFAs (acetic acid, propionic acid) |
8 g for bifidobacteria, fecal SCFAs |
| Fastinger, N. D. [104] (2008) The US |
38 | 19:19 around 27 |
double-blind | Resistant maltodextrin | ROS | 0 g (n = 12) 7.5 g (n = 13) 15 g (n = 13) |
3-week intervention |
↑: Bifidobacterium (nonsignificant) ↑: Proportion of propionic acid (linear) |
NO |
| Lefranc-Millot, C. [124] (2012) France |
48 | 24:24 28 |
double-blind | Resistant dextrin | ROS | 0 g(n = 12) 10 g (n = 13) 15 g (n = 12) 20 g (n = 11) |
2-week intervention |
↔: Bifidobacterium spp., Lactobacillus spp. ↑: Bacteroides ↓: Clostridium perfringens ↓: Colonic pH |
10 g for Bacteroides; 15 g for Clostridium perfringens; 20 g for colonic pH |
| Burns, A. M. [125] (2018) The US |
49 | 28:21 26.3 ± 6.8 |
double-blind cross-over |
Resistant maltodextrin | ROS | 0 g (n = 16) 15 g (n = 17) 25 g (n = 16) |
3-week intervention 2-week washout |
↑: Bifidobacteria | 25 g for bifidobacteria |
| Mai, V. [126] (2022) The US |
49 | 28:21 26.3 ± 6.8 |
double-blind cross-over |
Resistant maltodextrin | ROS | 0 g (n = 16) 15 g (n = 17) 25 g (n = 16) |
3-week intervention 2-week washout |
↑: Fusicatenibacter saccharivorans ↑: Akkermansia muciniphila, Faecalibacterium prausnitzii (in individuals with low baseline counts) |
25 g for Akkermansia muciniphila, Faecalibacterium prausnitzii |
a: Ratio of female subjects to male subjects; -- data not available. b: ↑ increased; ↓ decreased; ↔ unchanged; ↕ changed β-diversity.