Prebiotics and Probiotics for IBS: Do they help?

What are probiotics?

Probiotics are live, beneficial bacteria - similar to the ones already living in your gut. When consumed in large enough amounts, they can provide health benefits.

They’re best known for helping with antibiotic-associated diarrhoea, but they’re also commonly used to help improve digestive symptoms.

How do probiotics work?

Probiotics may help by:

• increasing the number or activity of beneficial bacteria 
• Preventing the growth of harmful microbes 
• supporting the gut lining and maintaining a healthy gut environment 

That said, they don’t work the same way for everyone. Your response will depend on your diet, your existing gut bacteria, and your overall health.

Do probiotics help IBS symptoms?

The evidence is mixed. Some studies show improvements in bloating, abdominal pain, and wind. Others show little or no effect. Differences in study design, duration, and the specific strains used make results difficult to compare.

Even expert guidelines don’t fully agree. The American Gastroenterological Association states there isn’t enough high-quality evidence to recommend probiotics for IBS.

However, the World Gastroenterology Organisation reports that reduced bloating and wind is a consistent finding across studies. Their advice is to choose a probiotic strain with evidence for your specific symptoms.

What’s a probiotic strain?

Think of bacteria like different models of cars. Each “model” - or strain - has its own unique features and effects. This matters because not all probiotics do the same thing. Choosing the right strain (or combination of strains) for your symptoms increases your chances of seeing a benefit.

Which probiotic strains are used for IBS?

Some strains with evidence in IBS include:

• Lactobacillus plantarum 299v – may help with abdominal pain and bloating 
• Bifidobacterium infantis 35624 – may improve overall IBS symptoms (found in Aflorex) 
• Multi-strain products are also available, such as Symprove and BioKult, which combine several types of bacteria.

You can find a helpful overview of research backed probiotics for IBS here:

Tips for trying probiotics

If you’re considering a probiotic, here’s how to approach it:

• Choose a product with evidence for IBS, ideally targeting your main symptom 
• Try one probiotic at a time 
• Take it consistently for 4–12 weeks 
• Track your symptoms to see if it’s helping 
• If there’s no improvement, try a different strain 

Also check the ingredients list. Some products contain added prebiotic fibres like inulin or FOS, which can worsen gas and bloating in IBS.

What are prebiotics?

Prebiotics aren’t bacteria — they’re food for the beneficial bacteria already in your gut.

They’re typically types of fibre that help these bacteria grow and produce compounds that support gut health.

Can prebiotics help IBS?

In theory, yes. Some people with IBS have lower levels of beneficial bacteria, and prebiotics may help support a healthier balance.

But in practice, it’s more complicated.

Many prebiotic fibres are also high in FODMAPs — which means they can trigger symptoms like gas and bloating.

Prebiotics in food

Prebiotic fibres are found in foods like onions, garlic, beans, wheat, asparagus, and chicory root.

These are nutritious foods, but they can be difficult to tolerate for people with IBS because they are high in FODMAPs.

A more practical approach is to include small, manageable portions of better-tolerated options, such as:

• oats 
• nuts and seeds (like almonds or chia) 
• small amounts (1-2 tbsp) of canned and rinsed pulses like chickpeas and lentils 

What about prebiotic supplements?

Prebiotics are also available as supplements, but the type matters.

• Inulin-type prebiotics (often from chicory root) are rapidly fermented and more likely to cause gas and bloating 
• Non-inulin types, such as β-GOS and Partially Hydrolysed Guar Gum (PHGG), are better tolerated by IBS sensitive tummies

Tips for using prebiotics

• Start with small amounts and build up slowly
• Focus on foods first, where possible
• If using a supplement, consider a non-inulin type
• If choosing inulin, keep doses low (under 6g per day)
• Pay attention to your own tolerance - this varies a lot

The bottom line

Both prebiotics and probiotics aim to support a healthier gut microbiome, but neither is a one-size-fits-all solution for IBS.

Probiotics may help some symptoms - particularly bloating and wind - but results vary depending on the strain and your existing gut microbiome.

Prebiotics can support beneficial bacteria, but they’re also more likely to trigger symptoms if introduced too quickly or in large amounts.

If you’re considering either, a targeted and gradual approach tends to work best.