Probiotic yeasts

Abstract

Probiotics are live microbial cells which on administration in adequate quantities confer health benefits to the host by stimulating the immune system, improving lactose absorption, production of enzymes and vitamins, reducing serum cholesterol, inhibition of pathogens, and antitumor properties. Recent evidence suggests that these effects are strain-specific and the dosage dependent. The most extensively studied and widely used probiotics are the lactic acid bacteria, Lactobacillus and Bifidobacterium spp. The only yeast reported to have probiotic effects is Saccharomyces boulardii, which has been shown to have promising effect as a probiotic due to its ability to survive during the passage through the human gastrointestinal (GI) tract, tolerating exposures to low pH and to bile salts, and its potential benefit is in getting relief from ailments such as acute diarrhoea in children and Clostridium difficile associated diarrhoea. The important aspects of probiotics like the characteristics of a microbe to be used as a probiotic, isolation of yeasts from different sources and their screening for probiotic properties, their mechanism of action, their potential benefits in the treatment of various diseases and various yeast probiotic products available in the market are discussed in this chapter. The safety issues concerning probiotic organisms have also been covered briefly.