Restrictions of exclusionary diets and their effects on the microbes

DietFood inclusionFood exclusionUC or CDMicrobial changesSCFABATrpReferences
EENLiquid formulaSolid foodCDReduced diversity
Decrease 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 acid
Increase in serotonin metabolites
↑ Melatonin
N-acetylserotonin
[8492]
CDEDInclude: chicken, eggs, potatoes, bananas, and apple (these are mandatory)Exclude: wheat, dairy, animal fat, processed foods, and red meatCD↑ Firmicutes
Clostridiales
Clostridia
Ruminococcuss
Roseburia
Oscillibacter
Haemophilus
Veillonella
Prevotella
Anarostipes
↓ Gammaproteobacteria
No changes in SCFANo changes in BADecrease in kynurenine and quinolic acid
Increase in serotonin metabolites
↑ Melatonin
N-acetylserotonin
[87, 91, 92]
PENLiquid formula and solid foodN/ACDN/AN/AN/ADecrease in kynurenine and increase in serotonin
[91, 92]
FODMAPInclude: certain fruits and vegetablesExclude: certain vegetables and fruits, wheat products, mushrooms, and honeyCD and UCRuminococcus torques
↓ Bifidobacterium (Bifidobacterium longum and adolescentis
↓ Clostridium cluster XIVa
Akkermansia muciniphila
Faecalibacterium prausnitzii
Decrease in SCFA and no changes seenDecrease in BAsHigher concentration of 3-indole propionic acid[108, 109, 112]
SCDInclude: fruits, meat and vegetablesExclude: grains, potatoes, corn, processed meat, and dairyCD and UCRoseburia
Eubacterium eligens
Blautia
Lachnospiraceae
Eubacterium
Ruminoccocus
Subdoligranulum
↓ Bacteroides
↓ Parabacteroides
F. prausnitzii
Clostridium
N/AN/AN/A[114, 116]
MDInclude: vegetables, fruit, whole grain, nuts, olive oil, and fishExclude: high red meat intake, processed foods, sugar, and processed meatCD 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 SCFA
Decrease in BCFA
Decrease in BAsDecrease of tryptophan and increase of IPA, ILA, IAA [132][128, 130]
PBDDaily intake of fruits, legumes, vegetables, potatoes, and yogurtAvoid sweetsCD and UCRoseburia
Ruminococcus
Streptococcus thermophiles
Bacteroides thetaiotaomicron
Clostridium clostridioforme
F. prausnitzii
Prevotella
Lachnospira
Clostridium cluster XIVa
Alistepes
Proteus mirabilis
Clostridium XIV
Bacteroides
Prevotella
Higher levels of SCFALower BAsLower kynurenine in serum
High 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