ABSTRACT
Contents 30.1 Probiotics-Viable by Definition ....................................................................................672 30.2 Mechanisms of Probiotic Health Effects and Role of Viability ........................................672 30.3 Adhesion to Intestinal Mucus and Epithelial Cells ..........................................................672 30.4 Inhibition of Growth and Adhesion of Pathogens ...........................................................673 30.5 Microbiota Modulation ...................................................................................................673 30.6 Intestinal Permeability ....................................................................................................674 30.7 Regulation of Immune System and Function ..................................................................674 30.8 Beneficial Effects of Probiotics and Role of Viability .......................................................676 30.9 Diarrhea ..........................................................................................................................676 30.10 Irritable Bowel Syndrome and Constipation ................................................................ 677 30.11 Inflammatory Bowel Disease ....................................................................................... 677 30.12 Helicobacter pylori Eradication ......................................................................................678 30.13 Bacterial Vaginosis and Candidiasis ..............................................................................679 30.14 Lactose Digestion ........................................................................................................ 680 30.15 Allergic Diseases .......................................................................................................... 680
30.15.1 Prevention of Allergies ...................................................................................... 680 30.16 Anticarcinogenic Effects ...............................................................................................681 30.17 Other Proposed Health Benefits .................................................................................. 682 30.18 Conclusions ................................................................................................................. 683 References ............................................................................................................................... 683
30.1 Probiotics-Viable by Definition According to the currently most popular definition of probiotics, issued by the Joint Food and Agriculture Organization/World Health Organization Working Group (Joint FAO/WHO Working Group Report on Drafting for the Evaluation of Probiotics in Food 2002), probiotics are “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” Thereby, viability is an essential requirement for probiotics and, strictly speaking, inactivated probiotics as well as isolated components and metabolites of probiotics fall outside the current definitions of probiotics. Nevertheless, in this review, in the lack of better terminology, we will refer to inactivated probiotics as well as isolated components and metabolites of probiotics as nonviable probiotics, while acknowledging the inherent self-contradiction of this term. In this chapter, the role of viability in the proposed health effects of probiotics is discussed by reviewing the literature on the mechanisms of the health effects with special focus on the requirement of cell viability, and by comparing the health efficacy documentation of nonviable probiotics with that of viable probiotics.
