Nick NorwitzMD PhD, Oxford-Harvard | Metabolic Health Educator | “Stay Curious”

Prebiotics, Probiotics, and Postbiotics: What's the Difference?

12 Jun 2025 · 1 min

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1:14

In this concise explanatory video, the presenter defines three key concepts in gut health. Prebiotics are described as non‑digestible food components—such as inulin and resistant starches—that act upstream of gut microbes to foster the growth of beneficial bacteria. Probiotics are living microorganisms found in fermented foods (yogurt, kefir, sauerkraut, kimchi) that directly support gut health. Postbiotics are the downstream bioactive metabolites produced by microbes, including short‑chain fatty acids (SCFAs), enzymes, and peptides, which execute health‑promoting effects throughout the body. The speaker emphasizes the sequential relationship (pre → pro → post) and provides concrete food examples for each category.

Chapters

Prebiotic. What does prebiotic mean? Pre means before, and prebiotics are non-digestible food components that come before, upstream of gut microbes, and are thought to promote the growth of beneficial gut bacteria. Examples include inulin and resistant starches. Probiotic. Pro refers to promoting, and it's easy to confuse prebiotic with probiotic. But whereas prebiotics are non-digestible food components, probiotics are living bacteria that support gut health. Fermented foods like live culture yogurts, kefir, and fermented vegetables like sauerkraut and kimchi are probiotics. And postbiotics— post refers to after, and postbiotics are the things that come after or downstream of gut microbes. And are bioactive compounds produced by microbes that ultimately execute on their health effects. Examples include short-chain fatty acids, SCFAs, enzymes, and peptides that support gut and whole body health.