The term ‘probiotic’ was first used by Lilley and Stillwell in 1965 to describe substances secreted by one microbe that stimulated the growth of another.

The friendly bacteria in our intestines comprise the beneficial types of bacteria found in the normal microflora of the human gut.

Humans have trillions of bacteria living in our intestines and there is increasing scientific research showing benefits of a balanced gut bacteria in health and wellness.

Probiotics are live microorganisms which, when administered in adequate amounts, confer a health benefit on the host.

A group of scientific experts assembled in London in 2013, to discuss the scope and appropriate use of the term probiotic. The panel’s conclusions were published in June 2014 and can be summarised as;

Probiotics have to be alive when administered. Concerns throughout the scientific literature resides in the;

  • viability and reproducibility on a large scale of the observed results,
  • viability and stability during use and storage
  • ability to survive in stomach acids and then in the intestinal ecosystem.

Only products containing live organisms shown in reproducible human studies to confer a health benefit should be claimed to be a probiotic.

The correct claim of health benefit, with solid scientific evidence, should be the element for the proper identification and assessment of the effect of a probiotic.

Probiotics must be taxonomically defined microbes (genus, species, and strain level). It is commonly admitted that most effects of probiotics are strain-specific and cannot be extended to other probiotics of the same genus or species.

The 2002 WHO guidelines recommend that, though bacteria may be generally recognized as safe, the safety of the potential probiotic should be assessed by the minimum required tests:

  • determination of antibiotic resistance patterns
  • assessment of certain metabolic activities
  • assessment of side effects during human studies
  • epidemiological surveillance of adverse incidents

The beneficial bacteria are made up of hundreds of different species, the main two of which are Lactobacillus and Bifidobacteria.  These bacteria are found in the normal microflora of the intestine.


LactobacillusLactobacillus is a type of bacteria. There are lots of different species of lactobacillus. These are ‘friendly’ bacteria that normally live in our digestive, urinary, and genital systems without causing disease. Lactobacillus is also in some fermented foods like yogurt and in dietary supplements



BifidobacteriaBifidobacterium is a genus of bacteria ubiquitous inhabitants of the gastrointestinal tract, vagina and mouth of humans. Bifidobacteria are one of the major genera of bacteria that make up the colon flora in mammals. Some bifidobacteria are used as probiotics.

History of Probiotics

The use of probiotics stretches back into a time before microbes were discovered. Fermented milk products were pictured in Egyptian hieroglyphs, and fermented yak milk has traditionally been used by Tibetan nomads to preserve milk during their long treks.

In the 1860s Louis Pasteur identified the bacteria and yeasts responsible for the process of fermentation, but did not link these microbes to any apparent health effects.

Nobel laureate Élie Metchnikoff, proposed in 1905 that it would be possible to modify the gut flora and to replace harmful microbes with useful microbes. After noting the association of longevity among Bulgarians, not to the yogurt they consumed, but rather to the lactobacilli used to ferment the yogurt and the presence of these lactobacilli in the colon.

In 1906, Henry Tissier isolated Bifidobacterium from an infant and claimed it could displace pathogenic bacteria in the gut. Tissier found that bifidobacteria are dominant in the gut flora of breast-fed babies and he observed clinical benefits from treating diarrhea in infants with bifidobacteria.

In the 1930s, the idea that yogurts were the best delivery vehicle for probiotics was questioned when the bacteria used as yogurt starters (Lactobacillus bulgaricus and Streptococcus thermophilus) were found incapable of colonizing the human intestine. A different strain, Lactobacillus acidophilus, was added to milk instead, as this species does not produce high levels of acid (causing curdling) and was also found to colonize the human colon.

In the 1950s–1980s, probiotic research focused on screening potential probiotic strains from isolates in nature or from human hosts, and defining the mechanisms of actions for probiotic strains.

Starting from around the year 2000, an exponential increase of the number of evidence-based clinical trials testing both efficacy and safety of these products has occurred. The sheer number of publications of clinical trials with hundreds of different types of probiotics makes it difficult for the public to know which probiotic is most appropriate. It is more important then ever to work with a qualified experience healthcare practitioner when prescribing probiotics.

These discoveries helped catalyze research into health-promoting microbes and their role in health and wellbeing.