ABSTRACT
Prebiotics and probiotics are components of foods that produce positive physiological effects through their interrelationships with the gastrointestinal tract. Whereas the benets of prebiotics have come to light in more recent years, recognition of probiotic effects dates back to the seventeenth century when Louis Pasteur postulated the importance of microorganisms in human life. More formalization to the study of probiotic organisms came about in 1908 when Eli Metchnikoff made observations that human health and longevity are associated with the ingestion of lactic acidproducing bacteria. His observation stemmed from the fact that Bulgarian peasants, who lived longer, consumed large quantities of sour milk containing what is now known as Lactobacillus bulgaricus.1 Prior to refrigeration, live bacteria and other microorganisms were commonly ingested in food as organisms were extensively
CONTENTS
13.1 Introduction .................................................................................................. 259 13.2 Denitions.....................................................................................................260 13.3 Colonization ..................................................................................................260 13.4 Mechanisms of Action .................................................................................. 262 13.5 Clinical Studies ............................................................................................. 262
13.5.1 Prebiotics .......................................................................................... 262 13.5.2 Probiotics ..........................................................................................264
