ABSTRACT
The concept of prebiotics was introduced in 1995 by Gibson and Roberfoid as an alternative approach to the modulation of the gut microbiota (Gibson and Roberfroid 1995). A more recent defi nition of the term is ‘‘a selectively fermented ingredient that allows specifi c changes, both in the composition and/or activity in the gastrointestinal microbiota that confers benefi ts upon host wellbeing and health’’ (Gibson et al. 2004). An ingredient must fulfi l three fundamental conditions in order to be considered as a prebiotic: (i) resistance to the digestion process, which involves gastric acids, intestinal brush border, pancreatic enzymes, etc.; (ii) fermentation by the large intestinal microbiota; (iii) a selective effect on the microbiota that has associated health-promoting effects (Charalampopoulos and Rastall 2012). Although all of these criteria are important, the third one is the most diffi cult to fulfi ll (Roberfroid 2007). Currently, a number of ‘prebiotic candidates’ that meet the fi rst two criteria still need to be validated as selective stimulators of intestinal bacteria associated with health and wellbeing.
