Probiotics: Microbial Therapy for Health Modulation

Abstract

The human gastrointestinal tract is a complex ecosystem that harbours a rich and diverse
microflora. These microbes live in harmony with the host and exert various beneficial effects on
human health by their metabolic activities. However, in our modern life style, frequent and
indiscriminate use of antibiotics has disturbed this microbial ecosystem, resulting in occurrence
of various bowel diseases. Some live microbial food supplements can re-establish this microbial
ecosystem. Such a group of microorganisms, which positively influences the intestinal microbiota
by stimulating the growth of beneficial bacteria and suppressing the harmful ones, is collectively
known as probiotics. These have been consumed in the form of fermented milk products for
centuries. However, scientific interest in their use for health maintenance and disease prevention
has emerged over the past few years only.
Various scientific evidences show that probiotics help to reduce several disorders including
diarrhea, inflammatory bowel diseases, urinary tract infections, hypertension, allergies, and cancer.
Besides, probiotics exert several other benefits also to human beings and animals. Important
issues in the probiotic therapy include selection of appropriate strain, its viability during storage,
gut persistence potential and functional properties. Another category involved in gut health is
prebiotics. These are non-digestible food ingredients, which beneficially affect the host by
selectively stimulating the growth or activity of one or a limited number of beneficial bacteria
in the colon. This review paper highlights the major health benefits of probiotic organisms,
mechanisms of their action, criteria of selection, enumeration, and safety of their use for human
health.