S. boulardii is a non-negotiable supplement in my own routine, and I wanted to share it here because, as you have probably noticed by now, the gut microbiome has me in a chokehold and I am completely obsessed. This yeast is something I am so excited to introduce, or re-introduce, you to, and I was thrilled to find such a solid body of research to bring along with it.
A quick note on how I work, because I think it is worth saying again: this is not a showcase of expertise. I come across something interesting in my clinical or academic work, decide it needs to be shared, compile what is out there, and bring it to you in a digestible way. References are always at the bottom and questions are always welcome.
In this issue:
Why S. boulardii being a yeast is actually the whole point
The three things it is doing once it gets to your colon
What the clinical data actually shows (and where it gets murky)
How it helps your microbiome recover without ever colonizing it
Two herbs that make sense alongside it, and how to time them
Most probiotic conversations start and end with bacteria. Lactobacillus, Bifidobacterium, the names you see on supplement labels and in the research literature, the organisms that have come to define what a probiotic even looks like in the popular imagination.
So, it tends to come as a surprise that one of the most clinically studied probiotics in gastroenterology belongs to an entirely different biological kingdom. Saccharomyces cerevisiae var. boulardii is a yeast, and understanding why that changes things is exactly where we are going to start.
