The words probiotics, prebiotics, and postbiotics may sound like variations of the same thing, but what a difference a prefix makes. The first is a category of health-promoting microbes. The latter two groups are types of beneficial molecules. But all three biotics are critical for supporting the community of microscopic organisms that live in the gastrointestinal tract, known as the gut microbiome. With both beneficial and harmful bacteria living in the human body, these diet-related factors—the biotics—help tip the balance in the positive direction. It’s important to understand their differences, as you’ll see, because each of these factors serves a distinct purpose, even as they work together.

Despite their importance for the gut microbiome, the health benefits of these biotics, which are present