Probiotics – evidence on strain and dose

Whilst probiotics have been around for centuries, in 2019, they’re seriously booming! In our recent podcast we sent expert nutrition researcher and educator, Dr Tim Crowe to break down the latest evidence on all things probiotics with Dr Jason Hawrelak, clinician and senior lecturer at the University of Tasmania, and founder and head researcher of the Probiotic Advisor Website.

What are probiotics?

The literature today suggests a rather strict definition – live microbes that when administered in adequate amounts confer a health benefit on the host. However, there are a few things about this definition worth teasing out.

Live Microbes.
Adequate amounts.
They confer a health benefit in the host.

According to the evidence, what’s the biggest health benefits from probiotics?

Over the last 20 years, the research has come such a long way. Where there used to be small single studies, we’re now at a stage of seeing large clinical trials, systematic reviews and meta-analyses.

There is high-level data of probiotics being proven useful for a range of conditions like:

During antibiotic therapy to reduce the risk of antibiotic associated diarrhoea, for the prevention and treatment of viral gastroenteritis.
Improving immune system function – where the evidence suggests there is a reduced risk of developing an upper respiratory tract infection, and reduced duration of nearly two days.

Yet all probiotics are not the same – looking at specific strains can also yield differing clinical benefits…

As an example, in reviewing some of the evidence for Lactobacillus Casei Shirota, there is reasonable level two and level three evidence, it can improve constipation; help with small bowel injury from NSAIDs; and even potentially, infections in children. But all of these conditions can vary depending on what strain you’re looking at, so it’s really not a blanket thing that all probiotics have the same effect.

Let’s talk the right probiotic with the right evidence…