What Are Prebiotics — and Why Do They Matter?

When we think about fiber, we often think of it as roughage — something that helps with digestion and keeps things moving. But not all fiber is created equal. Some types of fiber do far more than aid digestion; they actively feed the beneficial bacteria in your gut. These special fibers are called prebiotics.

Prebiotics act as fuel for your gut microbes, helping them grow and produce important compounds that support your immune system, metabolism, and even mental health. But here's the key: not all fiber is prebiotic.

True prebiotics include fibers like:

• Inulin – Found in garlic, onions, and chicory root. Inulin helps increase levels of Bifidobacteria in the gut, which are linked to improved digestion and immune health.
• Resistant starch – Found in cooked and cooled potatoes, green bananas, and oats. It feeds gut microbes that produce butyrate, a short-chain fatty acid known to support gut lining health and reduce inflammation.
• Oligosaccharides – Found in legumes, onions, and asparagus. These fibers promote microbial diversity and may help reduce bloating by improving overall gut balance.

Incorporating prebiotic-rich foods into your diet is one of the simplest and most effective ways to support a thriving microbiome. And since your gut plays a central role in digestion, immunity, mood, and even skin health, feeding your microbes may be one of the most impactful health decisions you make — starting with your next meal.