Why Fibre is the Unsung Hero of Gut Health (and Beyond)

We often hear about protein. How it fuels our muscles, keeps us full, and helps with recovery. But somewhere along the way, fibre has been quietly pushed aside. And yet, when it comes to gut health, hormone balance, skin health, and even brain function - fibre is the real star of the show.

In fact, I’d go so far as to say that most of my clients struggling with bloating, sluggish digestion, or constipation simply aren’t eating enough fibre, or enough variety of it. Many of them come to me after years of restrictive diets, often being told that fibrous or high-FODMAP foods are the cause of their symptoms. The end result? Their digestive system is left undernourished, lacking both fibre and microbial diversity, which can make symptoms worse in the long run.

Let’s look at why fibre is so important and how it plays a crucial role in supporting your microbiome, digestion, and overall wellbeing.

Fibre Feeds Your Microbes

Think of your gut as a rainforest - vibrant, diverse, and full of life. Every species (or microbe) has its own role to play, helping the whole ecosystem thrive. But when that diversity declines, through stress, antibiotics, processed food, or low-fibre diets, the ecosystem becomes fragile.

That’s where fibre comes in. It’s the fuel that feeds your gut microbes, allowing them to flourish and produce powerful by-products like short-chain fatty acids (SCFAs).

These SCFAs help:

• Strengthen the gut lining

• Reduce inflammation

• Regulate the immune system

• Support metabolic and even mental health

Without enough fibre, those beneficial bacteria simply starve, leaving more room for less helpful species to take over.

Pre-, Pro-, and Postbiotics — What’s the Difference?

You’ve probably heard of probiotics - the “good bacteria” found in fermented foods like kefir or sauerkraut, or supplements you can buy. But there’s a whole ecosystem of biotics at work:

• Prebiotics: the fuel for your good bacteria. These come from certain fibres and plant compounds found in foods like garlic, onions, leeks, bananas, asparagus, and oats.

• Probiotics: the live bacteria themselves - in fermented foods or supplements that help maintain a balanced gut microbiome.

• Postbiotics: the by-products your probiotics make after digesting prebiotics - including SCFAs, which have anti-inflammatory and immune-supportive effects.

Together, these three create a thriving internal environment where beneficial microbes can flourish.

Why We’re Not Getting Enough Fibre

Modern diets are typically high in protein and low in plants. While protein is important, too much of it (especially from animal sources) combined with too little fibre can wreak havoc on digestion.

This imbalance can lead to:

• Constipation – because fibre adds bulk and helps keep things moving.

• Higher cholesterol – fibre binds to cholesterol in the gut and prevents reabsorption, helping keep arteries clear.

• Blood sugar swings – fibre slows down glucose absorption, helping regulate blood sugar and reduce the risk of type 2 diabetes.

• Increased inflammation – low-fibre diets starve beneficial bacteria, reducing SCFA production and increasing gut permeability (“leaky gut”).

• Mood and cognitive changes – SCFAs made from fibre can calm inflammation in the brain and even support memory and focus.

  
  

It’s estimated that the average intake in the UK is around 20g a day, well below the recommended 30g. In contrast, traditional hunter-gatherer tribes, like the Hadza in Tanzania, eat up to 150g of fibre daily  and their gut diversity is astonishing.

How to Get More Fibre (and Keep Your Gut Happy)

Small changes can make a big difference. Here are some of my favourite ways to boost fibre and prebiotics naturally:

🥦 Eat a rainbow: Aim for 30+ different plant foods each week: Fruits, vegetables, grains, herbs, spices, nuts, and seeds all count.

🥔 Cook and cool starches: Cooling potatoes, rice, and pasta creates resistant starch, a prebiotic that feeds your gut bacteria.

🍓 Add berry powders or frozen berries: Easy to throw into smoothies or porridge for extra fibre and antioxidants.

🌾 Choose wholegrain alternatives: Swap white rice for brown or wild rice, and white flour for spelt or rye.

🥜 Make a nut and seed sprinkle: Blend mixed nuts or seeds and add them to yoghurt, soups, or salads.

💧 Hydrate: When you increase fibre, water is essential to keep your digestion moving smoothly.

Remember, fibre is not just one thing. The more variety you eat, the more diverse your gut microbes become. And microbial diversity is one of the strongest indicators of long-term health.

Recipe: Rainbow Prebiotic Power Bowl

Serves 1 | Prep: 10 min | Cook: 10 min

Ingredients:

• ½ cup cooked quinoa or brown rice

• 1 small handful of spinach or rocket chopped

• ¼ cup cooked chickpeas or lentils

• ¼ cup grated carrot

• ¼ cup red cabbage, thinly sliced

• 2 tbsp sauerkraut or kimchi (adds probiotics)

• A handful of radishes thinly sliced

• 1 tsp olive oil

• 1 tsp tahini

• Juice of ½ lemon

• Fresh herbs (parsley, coriander, or chives)

• Optional: sprinkle of seeds or nuts for crunch

Instructions:

1. Place the cooked quinoa or brown rice in a bowl.

2. Arrange the vegetables and legumes around the grain.

3. Add the sauerkraut or kimchi.

4. Drizzle with olive oil, tahini, and lemon juice.

5. Sprinkle with fresh herbs and seeds/nuts.

6. Gently toss to combine, and enjoy!

Why this works:

• Prebiotic fibre: Carrot, cabbage, lentils, and chickpeas feed beneficial gut bacteria.

• Probiotics: Sauerkraut or kimchi help support gut diversity.

• Variety & colour: Different colours = different polyphenols and nutrients to nourish your microbes.

NOTE: For many people, especially those who have been restricting fibrous or high-FODMAP foods for a long time, it’s important to increase fibre gently.

Suddenly adding lots of fibre without supporting digestion can sometimes trigger bloating or discomfort.

In some cases, underlying imbalances in the microbiome or insufficient digestive function need to be addressed first, so the body can properly process and benefit from these prebiotic foods.

The Takeaway

Fibre isn’t just about regularity - it’s about resilience.

By feeding your microbiome, balancing your blood sugar, supporting your liver and brain, and protecting future generations of gut microbes, it truly is one of the most powerful nutrients for lifelong health.

So while protein might get the headlines, fibre deserves the spotlight.

Your gut, and your whole body will thank you for it.

Want to See What’s Happening Inside Your Gut?

If you’re curious about how your microbiome is doing, whether you have enough diversity, if certain bacteria are over- or underrepresented, or if your gut is struggling with inflammation - the Microbiome Explorer Comprehensive stool test can provide those answers.

• This comprehensive test looks at:

• The balance and diversity of your gut microbes

• Levels of beneficial species like Akkermansia and Bifidobacterium

• Markers of digestion, inflammation, and gut barrier health

The Microbiome Explorer test is a powerful way to understand how well your gut ecosystem is functioning, and how fibre and prebiotic-rich foods could help restore balance.

If you’d like to learn more about the Microbiome Explorer test and whether it’s right for you, send me an email. Together, we can uncover what your gut really needs to thrive.

sarah@brighternutrition.co.uk