Table 1.

Biological factors that can affect the health of the host.

Name	Definition	References
Probiotics	live microorganisms that, when administered in adequate amounts, confer a health benefit on the host	[7]
Prebiotics	a substrate that is selectively utilized by host microorganisms conferring a health benefit	[8]
Synbiotics	a mixture comprising of live microorganisms and substrate(s) selectively utilized by host microorganisms that confers a health benefit on the host	[9]
Postbiotics	preparation of inanimate microorganisms and/or their components that confers a health benefit on the host	[10]
Paraprobiotics	non-viable microbial cells (either intact or broken), or crude cell extracts, which, when administered (orally or topically) in adequate amounts, confer a benefit on the human or animal consumer	[11]
Psychobiotics	probiotics that confer mental health benefits to the host when consumed in a particular quantity through the interaction with commensal gut bacteria	[12,13,14,15]