Table 5.

Types of modulation of the gut microbiota.

Type of Modulation	Mechanism	Side Effects
Diet	A highly digestible diet reduces the storage of undigestible substrate in the intestinal lumen [72,73].	Only in the case of food hypersensitivity or difficult to digest food [32].
Prebiotics	Production of SCFAs for the growth of beneficial bacteria, binding of deleterious bacterial metabolites (e.g., psyllium has BA- binding properties) [39,70].	Sometimes flatulence, diarrhoea [32].
Probiotics	Improvement of barrier function, immunomodulatory and antimicrobial effect [74].	Rare [32].
Synbiotics	Products that contain probiotics and prebiotics.
Antibiotics	Reduction of total bacterial load, suppression of immune stimulation, and conversion of toxic metabolites [66,67].	-Long-term changes in the microbiota composition. -Risk of antimicrobial resistance [32].
Postbiotics	Immunomodulatory, anti-inflammatory, antioxidant, and anticancer effects [30].	Rare [30].
FMT	Reconstruction microbial composition and some microbial-derived metabolites [32].	Diarrhoea, flatulence, bloating, fever, vomiting [2,3].