Table 1.

Inclusion and exclusion criteria

Criteria	Inclusion criteria	Exclusion criteria
Population	Adults over 18 years old. Diagnosed with T2DM, or suffering from any MetS components or combinations of these components.	Children. Non-T2DM individuals. Healthy subjects not suffering from any MetS components.
Intervention	BFFs and beverages. May contain any concentration of any types of live microorganisms, or no live microorganisms at time of consumption. Sole intervention.	Single compound extracts. BFFs mixed with non-fermented ingredients. BFFs as part of whole diet interventions. Coffee, tea, chocolate, beer, wine, high alcoholic beverages.
Comparator	Placebo, no intervention or active control groups.	Any other type of intervention or comparison.
Outcome	Related to target conditions (T2DM, MetS). Changes in anthropometric measurements, blood pressure, lipid profile, glucose metabolism/glycaemic control, inflammatory markers, gut microbiota composition and metabolites. Others: liver markers, quality of life, mental health scales, adverse events.	Not related to target conditions.
Study design	All clinical randomised controlled trials.	All other study designs.
Language	All languages.	None.
Setting	All settings.	None.

BFFs, botanical fermented foods; MetS, metabolic syndrome; T2DM, type 2 diabetes mellitus.