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Probiotic origins and residential and transient strains explained
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Untangling common misconceptions of probiotic origins and strains

As probiotics continue to gather pace in the industry, one commonly discussed topic is the origin of probiotics, and this can lead to a number of misconceptions and misunderstandings.

Various terminologies describing probiotics as ‘naturally derived’, ‘of human origin’ or ‘naturally found in the human gut’ are increasingly used across communications and consumer messaging. As well as being isolated from the human gastrointestinal (GI) tract, probiotic strains can be isolated from a variety of sources, including environmental samples and food. For consumers, this can cause confusion within a landscape which is already vast and can sometimes feel overwhelming.

So, what impact does a probiotic’s origin have on its effectiveness and what is the most important criteria for selecting a probiotic strain?

Transient and residential strains

The topic of transient and residential strains is frequently discussed, and can also seem confusing to consumers.

Residential strains reside in the gut and establish a stable long-term presence. Meanwhile transient strains, also known as ‘non-residential’, do not colonise and establish in the body. Instead, they enter the body from foods or certain dietary supplements and pass through the GI system, where they may interact temporarily with the host to aid digestion, influence the immune system, modulate the gut environment and microbial diversity, among other effects.

What is often not known is that transient and residential bacteria are not mutually exclusive. The human gut microbiome, like all microbiomes, is not a static entity – it is a highly dynamic community, constantly evolving and buzzing with life. It is shaped by our lifestyle, our environment and our inheritance.

“We each have our very own, very unique microbiomes,” said Stine Ninel Hansen, Global Scientific Advisor at Chr. Hansen, in a recent Spotlight On broadcast, Demystifying probiotic origins: exploring the benefits of transient bacteria​. 

“Microbiomes fluctuate in response to numerous factors. The gut microbiome is highly diverse, consisting of trillions of microorganisms, the majority of these being bacteria, belonging to thousands of different species.

“This unique gut microbiome changes throughout our entire life. A strain that is residential at one age might be transient at another age.”

This is why both transient and residential bacteria can play an important role in contributing to a well-balanced microbiome. There is significant clinical evidence that many transient strains deliver long-lasting health benefits by restoring balance, even by simply passing through the gut. Science has shown that some of the health benefits conferred by transient strains include pathogen inhibition, barrier function and immune interactions.  

For example, in a clinical study carried out by Chr. Hansen and introduced by Anja Wellejus, Senior Manager and Head of Human Health Research at Chr. Hansen, in the recent Spotlight On broadcast, the study showed that “both residential and transient bacteria can offer beneficial effects for infants.”

The most important criteria when selecting a probiotic strain should be the clinical documentation on the strain and its effect on humans.

Missed the Spotlight On broadcast?

Register here​ to watch on demand and join our expert speakers as they present clinical studies and discuss how our constant interaction with the ever-present microorganisms found in natural surroundings has shaped and evolved the human microbiome over time.

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