Table 1.

Summary of inclusion and exclusion criteria employed for the studies’ selection.

	INCLUSION CRITERIA	EXCLUSION CRITERIA
Intervention	Oral intake of the NNS (aspartame, acesulfame-K, sucralose, saccharin)	Non oral NNS administration routes
Comparator	Placebo or standard diet	No control
Outcome	Expressed employing 16S RNA microbiota profiling or qPCR analysis	Not shown
Study Design	Randomized control trial, intervention trial (non-randomized, quasi-experimental), observational trial, pre-clinical in vivo study	Case reports, commentary, meta-analysis, systematic review, letters to the editor, in vitro or ex-vivo studies
Publication	Peer-reviewed paper	Congress abstracts, thesis reports, grey literature