Restrictions of exclusionary diets and their effects on the microbes
Diet | Food inclusion | Food exclusion | UC or CD | Microbial changes | SCFA | BA | Trp | References |
---|---|---|---|---|---|---|---|---|
EEN | Liquid formula | Solid food | CD | Reduced diversityDecrease in Bacteroides/Prevotella ratio↑ Firmicutes↑ Alistepes↓ Faecalibacterium↓ Proteobacteria↑ Roseburia↑ Oscillibacter↓ Haemophilus↓ Veillonella↓ Prevotella↓ Anarostipes | Decrease in SCFA (returned to baseline with reintroduction of solid food) | Decrease of PBA and increase in SBA (returned to baseline after reintroduction of solid food) | Decrease in kynurenine and quinolic acidIncrease in serotonin metabolites↑ Melatonin↑ N-acetylserotonin | [84–92] |
CDED | Include: chicken, eggs, potatoes, bananas, and apple (these are mandatory) | Exclude: wheat, dairy, animal fat, processed foods, and red meat | CD | ↑ Firmicutes ↑ Clostridiales↑ Clostridia↑ Ruminococcuss↑ Roseburia ↑ Oscillibacter↓ Haemophilus↓ Veillonella↓ Prevotella↓ Anarostipes↓ Gammaproteobacteria | No changes in SCFA | No changes in BA | Decrease in kynurenine and quinolic acidIncrease in serotonin metabolites↑ Melatonin↑ N-acetylserotonin | [87, 91, 92] |
PEN | Liquid formula and solid food | N/A | CD | N/A | N/A | N/A | Decrease in kynurenine and increase in serotonin | [91, 92] |
FODMAP | Include: certain fruits and vegetables | Exclude: certain vegetables and fruits, wheat products, mushrooms, and honey | CD and UC | ↑ Ruminococcus torques↓ Bifidobacterium (Bifidobacterium longum and adolescentis↓ Clostridium cluster XIVa↓ Akkermansia muciniphila↓ Faecalibacterium prausnitzii | Decrease in SCFA and no changes seen | Decrease in BAs | Higher concentration of 3-indole propionic acid | [108, 109, 112] |
SCD | Include: fruits, meat and vegetables | Exclude: grains, potatoes, corn, processed meat, and dairy | CD and UC | ↑ Roseburia ↑ Eubacterium eligens↑ Blautia↑ Lachnospiraceae↑ Eubacterium↑ Ruminoccocus ↑ Subdoligranulum↓ Bacteroides↓ Parabacteroides↑ F. prausnitzii↑ Clostridium | N/A | N/A | N/A | [114, 116] |
MD | Include: vegetables, fruit, whole grain, nuts, olive oil, and fish | Exclude: high red meat intake, processed foods, sugar, and processed meat | CD and UC | ↑ Roseburia↑ Lachnospira↑ Prevotella↑ Ruminococcuss bromii↑ Flavonifractor plautii↑ Butyricicoccus↑ Faecalibacterium prausnitzii↑ Clostridium cluster↑ Bacteroidetes↓ Proteobacteria↓ E. coli↓ Proteobacteria↓ Bacillaceae↓ R. torques↓ R. gnavus↓ Bilophila wadsworthia | Increase of SCFADecrease in BCFA | Decrease in BAs | Decrease of tryptophan and increase of IPA, ILA, IAA [132] | [128, 130] |
PBD | Daily intake of fruits, legumes, vegetables, potatoes, and yogurt | Avoid sweets | CD and UC | ↑ Roseburia↑ Ruminococcus↑ Streptococcus thermophiles↑ Bacteroides thetaiotaomicron↑ Clostridium clostridioforme↑ F. prausnitzii↑ Prevotella ↑ Lachnospira↓ Clostridium cluster XIVa↓ Alistepes↓ Proteus mirabilis Clostridium XIV↑ Bacteroides↑ Prevotella | Higher levels of SCFA | Lower BAs | Lower kynurenine in serumHigh levels of Trp | [125, 136, 139, 140] |
EEN: exclusive enteral nutrition; CDED: Crohn’s disease exclusion diet; PEN: partial enteral nutrition; FODMAP: fermentable oligo-, di-, mono-saccharide and polyol; SCD: specific carbohydrate diet; MD: Mediterranean diet; PBD: plant-based diet; UC: ulcerative colitis; CD: Crohn’s disease; SCFA: short chain fatty acids; BCFA: branched chain fatty acids; BA: bile acids; Trp: tryptophan; PBA: primary bile acids; SBA: secondary bile acids; IPA: indole-3-propionic acid; ILA: indole-3-lactic acid; IAA: indole-3-acetic acid. ↑: increase in relative abundance; ↓: decrease in relative abundance; N/A: not applicable
We thank Prof. B. Witteman (emeritus from Wageningen University and Research, Wageningen, The Netherlands) for stimulating discussions during the preparation of the manuscript, and Dr. T. Dinse (University College Roosevelt, Middelburg, The Netherlands) for correcting the language and style of the manuscript.
HM: Conceptualization, Investigation, Writing—original draft, Writing—review & editing. GR: Validation, Writing—review & editing, Supervision. Both authors read and approved the submitted version.
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