Prebiotics vs. Probiotics: The Basics

Daniel Gigante
Sep 8
2 min read

When it comes to gut health, people often talk about probiotics—the live, beneficial bacteria that support digestion, immunity, and overall well-being. But fewer people understand prebiotics—the fibers that feed those good bacteria.

Think of your microbiome as a garden:

Probiotics are the seeds (the living bacteria).
Prebiotics are the fertilizer (the food that helps them grow).

For a truly healthy gut, you need both.

What Are Probiotics?

Probiotics are live microorganisms, mostly bacteria and yeast, that support gut health. They help:

Balance the microbiome by crowding out harmful bacteria
Support nutrient absorption
Strengthen the immune system

Examples of probiotic-rich foods:

Yogurt (with live cultures)
Kefir
Kimchi
Sauerkraut
Miso

What Are Prebiotics?

Prebiotics are types of dietary fiber that your body can’t digest—but your gut bacteria can. When good bacteria “eat” prebiotics, they produce short-chain fatty acids (SCFAs) like butyrate, which nourish the gut lining and reduce inflammation.

Examples of prebiotic-rich foods:

Garlic
Onions
Asparagus
Bananas (slightly green)
Chicory root
Whole grains

Why You Need Both

On their own, probiotics can help, but without prebiotics to feed them, they may not thrive or stick around. Prebiotics alone won’t introduce new bacteria, but they fuel the beneficial microbes already living in your gut.

When used together, they create a synbiotic effect—enhancing each other’s benefits and supporting:

Better digestion and regularity
Stronger immune defense
Reduced inflammation
Improved nutrient absorption

What Science Says

A 2020 review in Nutrients found that combining prebiotics and probiotics resulted in more consistent improvements in gut health compared to taking either one alone. The study highlighted better microbiome balance, fewer gastrointestinal symptoms, and enhanced immune responses in participants.