Probiotics, Prebiotics and Postbiotics... What are the differences?

Gut health is a hot topic for good reason—it impacts everything from digestion and immunity to mental wellbeing. But with all the talk of prebiotics, probiotics, and now postbiotics, it can get confusing. So let’s break it down simply and look at when you might need each.

Probiotics: The Live Helpers

These are live bacteria found in fermented foods like yoghurt, kefir, kimchi, and some supplements. Their job? To help restore or maintain a healthy balance of gut bacteria—especially useful after antibiotics, periods of high stress, illness, or when experiencing symptoms like bloating or irregular bowel movements.

When to consider them:

• After a course of antibiotics

• During or after a gut infection

• When dealing with IBS, bloating, or diarrhoea

• For immune support, especially in winter

• For inflammatory conditions

Prebiotics: Food for Your Good Bacteria

Think of these as the fuel for probiotics. Prebiotics are fibres (like inulin or resistant starch) found in foods such as garlic, onions, leeks, bananas, and oats. They pass through your digestive tract undigested and feed the beneficial bacteria in your gut.

When to focus on them:

• To support long-term gut health

• After taking a probiotic so that you can supply the food that they need to thrive

• If you’re generally healthy but want to boost your microbiome

• When increasing fibre intake for better digestion and blood sugar control

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Postbiotics: The Byproducts with Benefits

Postbiotics are the compounds that probiotics produce when they break down prebiotics-things like short-chain fatty acids and peptides. Butyrate is one of the main postbiotics and the most commonly supplemented one. They help reduce inflammation, support the gut lining, and communicate with your immune system.

When they’re important:

• In people with sensitive guts where live probiotics might cause discomfort

• For calming gut inflammation or supporting immune function

• As a safe option for those with severe gut dysbiosis

  
  

So, do you need all three? Not necessarily. For most healthy individuals, a diet rich in fibre and fermented foods is enough. But in times of imbalance (illness, antibiotics, digestive issues), targeted use of probiotics or postbiotic supplements, alongside prebiotics, can help restore balance. I generally recommend postbiotics to people with auto-immune conditions or those with severe gut abnormialties.

As always, it’s best to personalise your approach. If you're unsure which one your gut needs, consult with a registered dietitian to tailor a plan that works for you.

Let me know if you’d like to tailor this further for your specific practice or audience!

Interested in boosting your gut microbiome? Try my Gut Health Reset Guide- a comprehensive guide to understanding the gut microbiome and including a 10 day Gut Reset with amazing recipes.

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