What are probiotics?

Probiotics are often thought of as ‘friendly bacteria’, however there’s a bit more to it than that.

Probiotics are ‘live microorganisms which when administered in adequate amounts, confer a health benefit on the host 1,2

Some probiotics can help balance the numbers of beneficial and potentially harmful bacteria in the digestive system, and therefore support the function of the intestinal microbiota. 

Lactic acid bacteria, with prominent species including Lactobacillus, and bifidobacteria, are commonly selected as probiotics, although other microorganisms (including the yeast, Saccharomyces boulardii) can also be considered probiotic.

The Probiotic Concept & Relevance Today

The probiotic concept dates back to the early 20th century, with Professor Elie Metchnikoff’s theory that there were health advantages in replacing harmful proteolytic bacteria in the colon with beneficial saccharolytic species, preferably those producing lactic acid.

In the present day, we are less exposed to bacteria in the diet and environment as a result of modern hygiene practices and an increased intake of highly processed foods (which do not contain bacteria). Therefore, exposure to bacteria in number and diversity has decreased. This, alongside many aspects of modern life that disrupt the gut microbiota (i.e. medication, poor diet, stress and illness) highlights the relevance and potential application of probiotics today.

Considering a probiotic

Not all probiotics are the same; the characteristics, actions and health benefits can be strain-specific and therefore it is important to consider the following when choosing a probiotic: 

1) Labels should state the full name of the strain and minimum count of live cells at end of shelf-life, supported by quality control procedures

• The specific strain in full (Lactobacillus casei Shirota), and the minimum count of live bacteria at end-of shelf life (6.5 billion live cells per 65ml bottle) is stated on Yakult’s packaging.

• Each batch of Yakult is checked by a quality control laboratory to ensure a minimum count of live cells at end of shelf life.

2) Probiotic strains must be safe

• Lactic acid bacteria have been consumed for centuries in fermented foods and the Lactobacillus casei Shirota in Yakult has been consumed for over 80 years.  

3) Scientific evidence supporting survival through the gut

• For oral probiotics, are there human intervention trials showing survival of the strain though the gut?

4) Scientific evidence supporting efficacy

• Check for trials and studies for the probiotic and the particular patient problem – this is important for assessment of safety too. 

Probiotic Flowchart IMAGE_Full Size


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