Hello there! What an interesting and somewhat challenging question!
First, let's talk a little about probiotics. Probiotics, as defined by the World Health Organization, are "live microorganisms which when administered in adequate amounts confer a healthy benefit to the host." What that means is that it's the healthy microorganisms found in yogurt, kimchi, fermented mustard leaf, and sauerkraut, to name a few, that are good for your gut. The key here is that these microorganisms are live.