Probiotics vs Prebiotics: What's the Difference?

Probiotics and prebiotics sound almost identical, get mentioned in the same breath, and confuse just about everyone. But they're two different things that do two different jobs — and understanding the difference makes it much easier to look after your gut. Here's the simple version.

The one-line difference

Probiotics are the good bacteria. Prebiotics are the food that feeds them. That's the whole thing in a sentence. Probiotics add helpful microbes to your gut; prebiotics are the fibres those microbes eat so they can grow and thrive. They work as a team.

What are probiotics?

Probiotics are live beneficial bacteria that, in the right amounts, support a healthy gut. You get them mainly from fermented foods:

• Live yoghurt
• Kefir
• Sauerkraut and kimchi (the refrigerated, unpasteurised kind)
• Miso and tempeh
• Other fermented vegetables

They help top up and diversify the good bacteria already living in your gut.

What are prebiotics?

Prebiotics are types of fibre your body can't digest, but your good gut bacteria can. By feeding those bacteria, prebiotics help them flourish. Good sources include:

• Onions, garlic and leeks
• Oats and barley
• Bananas (especially slightly underripe)
• Asparagus
• Apples, beans and lentils

(If some of these bloat you, use smaller amounts — many are also common trigger foods, which we cover in our guide to foods that cause bloating.)

Why you need both

Adding probiotics without prebiotics is like introducing helpful bacteria and then not feeding them. Eating prebiotics without enough good bacteria around means less benefit from the fibre. Together, they help build a diverse, resilient gut — which is why a varied diet with both fermented foods and plenty of plant fibre beats relying on either alone.

Do you need supplements?

For most healthy people, food first is a sensible approach. A varied diet of fermented foods and fibre-rich plants naturally covers both. Probiotic supplements can have a place — some people use them after a course of antibiotics, for example — but they're not a substitute for good eating, and quality varies a lot between products. If you're considering one for a specific health reason, it's worth a word with your doctor or a dietitian.

The simplest way to use this

You don't need to track grams or buy anything fancy. Aim to include some fermented food most days, eat a wide variety of plants, and build up gradually so your gut adjusts comfortably. For the foods that do the most, see the best foods for gut health.

Want it built into a simple daily plan? The 30-Day Gut Reset works both into your routine step by step, or start with the free 7-day anti-bloat plan.

Frequently asked questions

Should I take prebiotics or probiotics first?

You don't have to choose — they work together, and a varied diet gives you both. If anything, make sure you're feeding your gut bacteria with prebiotic fibre, not just adding probiotics.

Can you take prebiotics and probiotics together?

Yes, and it's ideal — the prebiotics feed the probiotics. Products that combine both are sometimes called “synbiotics,” but you can get the same effect from food.

What foods have both probiotics and prebiotics?

No single food is rich in both, which is why variety matters. Pair fermented foods (yoghurt, kefir, kimchi) with prebiotic foods (oats, onions, bananas) across your meals.