What are Probiotics?

Probiotics have been defined as “live microorganisms that, when administered in adequate amounts, confer a beneficial effect on the health of the host”.

For centuries, living microorganisms, particularly lactic acid bacteria (producers of lactic acid from sugar) have been used in food preservation. In 1907, Metchnikoff observed that the consumption of large quantities of fermented milk products containing bacteria contributed to the long and healthy lives of Bulgarian peasants.

In 1965, the term “probiotic” was originally proposed as an alternative to the term “antibiotic”, to describe substances secreted from microorganisms that promoted the growth of another microorganism.

The most widely used and extensively studied probiotic organisms belong to the lactic acid bacteria (LAB) and bifidobacteria, particularly Lactobacillus spp. and Bifidobacterium spp. These bacteria are generally recognised as safe, based upon their long history of safe use.

The human gastrointestinal (GI) tract houses a complex, but relatively stable microbial population. We have 100,000 billion viable microbes in our intestine, comprising more than 1,000 species. It is acquired from the environment as an infant is born and develops throughout the first years of life, being fully-formed and acquiring adult characteristics by around two years of age.

The microbiota has a wide range of functions, and this list is growing as our understanding develops and we start to appreciate how fundamental these bacteria are to human health.