How fibre and personalisation is being rethought by scientists

A New Fibre Frontier: How Scientists Are Rethinking Fibre to Personalise Nutrition

For decades, we’ve divided dietary fibre into two neat categories: soluble and insoluble. Simple, right? One dissolves in water, the other doesn’t. But what if that distinction is no longer enough to guide optimal health?

A groundbreaking study from researchers at the University of Melbourne¹, published in Food Research International, suggests that it’s time to move beyond this outdated binary. Instead, they propose a new, functional way to classify fibre: one that could bring us closer to truly personalised nutrition and targeted microbiome support.

Let’s unpack what makes this proposal so promising and why it could revolutionise how we use fibre as a tool for health.

Why Fibre Deserves More Scientific Precision

We already know that fibre fuels our gut microbiome, the vast ecosystem of microbes that influences digestion, immunity, metabolic control, and even brain function. Fibre is one of the few dietary components that directly feed these microbes, making it a cornerstone of long-term health.

Yet, despite its importance, we’ve long lacked a refined system for categorising fibres based on how they behave in the body.

Enter the new model: a five-feature framework that looks at how fibre interacts with the gut, the microbiome, and our total physiology.

The 5 Characteristics That Define Fibre Functionality

The proposed classification outlines five key properties that determine how fibres influence health outcomes:

1. Backbone Structure: The chemical architecture of the fibre, such as beta-glucans or inulin, impacts how microbes break it down.
   
2. Water-Holding Capacity: How well the fibre retains moisture, affecting stool consistency, gut motility, and satiety.
   
3. Structural Charge: Some fibres carry electrical charges that influence how they interact with the gut lining and bacteria.
   
4. Fibre Matrix: Whether the fibre is embedded in a whole food matrix or isolated, impacting its accessibility to microbes.
   
5. Fermentation Rate: How quickly gut bacteria ferment the fibre, which influences gas production, SCFA release (like butyrate), and colonic health.
   

This more nuanced system allows researchers and clinicians to move beyond “soluble” vs “insoluble” and instead start predicting how different fibres might affect gut ecology, inflammation, metabolic outcomes, and more.

From One-Size-Fits-All to Precision Nutrition

The long-term vision? A prescriptive approach to fibre, much like how we tailor medications for specific conditions. Imagine being able to choose fibres based on their fermentation rate to soothe an inflamed colon or selecting water-retaining fibres to support bowel regularity in IBS.

The Melbourne team has already started this journey by examining 20 different types of fibre. They mapped out how each interacts with the microbiome. They hope to eventually offer clinical guidance on which fibres are most beneficial for different gut or metabolic states.

What Should We Do While Research Catches Up?

While we wait for precision fibre science to make its way into clinical practice, there are still tried-and-true principles we can follow today:

• Aim for 30g of fibre per day: This is the benchmark set by health agencies and supported by decades of gut health research².
  
• Diversify your fibre sources: Think: legumes, whole grains, fruit, vegetables, nuts, and seeds. Each plant contains a unique fibre matrix that feeds different microbes³.
  
• Focus on variety, not perfection: The more plant types you eat in a week, the more diverse your microbiome, and the better your gut health^4,5.
  

Looking Ahead: Fibre as a Therapeutic Tool

This new classification marks an exciting step towards fibre personalisation. Think about this: a future where we match the right fibre to the right person at the right time.

It’s a reminder that nutrition is no longer just about hitting macros or counting calories. It’s about understanding the functionality of food, especially when it comes to how our microbiome processes what we eat.

In this light, fibre isn’t just roughage. It’s a sophisticated, dynamic interface between diet and health – one we’re only beginning to understand.

References

1. Beyond soluble and insoluble: A comprehensive framework for classifying dietary fibre’s health effects: https://www.sciencedirect.com/science/article/pii/S0963996925001802?via%3Dihub
2. Fibre intake for optimal health: how can healthcare professionals support people to reach dietary recommendations? https://pmc.ncbi.nlm.nih.gov/articles/PMC9298262/ 
3. Recommended daily intake of fibre and fibre-rich foods to help you achieve it: https://www.eufic.org/en/whats-in-food/article/recommended-daily-intake-of-fibre-and-fibre-rich-foods-to-help-you-achieve-it 
4. American Gut: an Open Platform for Citizen Science Microbiome Research: https://journals.asm.org/doi/10.1128/msystems.00031-18 
5. Why should you eat 30 plants a week? https://zoe.com/learn/30-plants-per-week