Prebiotics vs. Probiotics: What's the Difference?

"Prebiotic" and "probiotic" sound similar and are often printed on the same products, which makes it easy to assume they are versions of the same thing. They are not. This guide compares them directly, using the four questions people most often ask.

The Short Version

• Probiotics are live microorganisms. When consumed in adequate amounts, they may confer a benefit to the host. Yogurt, kefir, sauerkraut and probiotic capsules all fall in this category.
• Prebiotics are compounds - most often fibers like inulin, FOS and GOS - that your body does not digest but that gut microorganisms can use as food.

A simple memory device: probiotics add microbes, prebiotics feed microbes.

Side-by-Side Comparison

Why the Distinction Matters on a Label

Because the two categories are different kinds of things, they are described differently on supplement labels:

1. Probiotic labels identify organisms, usually with a genus, species and strain, and often a CFU (colony-forming unit) count at the time of manufacture.
2. Prebiotic labels identify ingredients, with weights in grams or milligrams per serving.

If a product contains both, it may be marketed as a "synbiotic." The term describes the combination - it does not automatically mean the combination has been tested or shown a particular result. See What Are Synbiotics? for more.

Common Points of Confusion

• "Does a prebiotic contain bacteria?" No. Prebiotics are fibers and similar compounds. Any live cultures in a product come from separate probiotic ingredients.
• "Is fiber the same as a prebiotic?" Not exactly. All prebiotics are substrates for gut microbes, but not every dietary fiber meets the stricter definition of a prebiotic. See What Are Prebiotics? for the full explanation.
• "Do you need both?" There is no single correct answer for everyone. Foods supply both fermentable fibers and, in some cases, live cultures. What suits you depends on your diet and circumstances, and a healthcare professional can help you think it through.

The Takeaway

Probiotics and prebiotics play different roles: one category is live microorganisms, the other is the fiber-like compounds those organisms can use. Knowing which one a product actually contains - and how much per serving - is the most useful first step in evaluating any "gut health" claim on a package.

If you want to see how these terms look on a real label, the Pro-Active Greens category on MarketPlace Global lists the current formula and ingredient details.