Fibre is often seen as just a digestion aid, but it actually impacts everything from gut health to hormones and mental clarity. Most people fall short, not only in quantity, but in variety! Understanding how fibre works and why diversity matters is key to unlocking its full benefits
Why fibre matters
Fibre is one of the most under-consumed nutrients in the UK, yet it plays a central role in gut, metabolic and mental health (1.)
When certain types of fibre reach the large intestine, they are fermented by gut bacteria. This produces short chain fatty acids such as butyrate, which help:
- Support the integrity of the gut lining
- Regulate inflammation
- Influence immune function
- Support metabolic health
This is where fibre connects directly to the gut brain axis. Signals from the gut microbiome can influence neurotransmitters, stress response and cognition, linking fibre intake to mood and mental clarity (2.)
Fibre also plays a role in hormone regulation and skin health. By supporting regular bowel movements, fibre helps with the excretion of excess hormones such as oestrogen. Poor fibre intake can contribute to hormonal imbalance, which may present as acne, PMS symptoms or sluggish digestion (7.)
Not all fibre feeds the gut
A key point that is often missed is that not all fibre directly feeds gut bacteria. Fibre can be broadly split into two main types, each with different roles:
Soluble fibre
This type dissolves in water and is often fermentable. It is the primary fuel source for beneficial gut bacteria.
Key functions:
- Feeds the microbiome
- Produces short chain fatty acids
- Supports blood sugar regulation
- Helps lower cholesterol
Common sources include oats, legumes, flaxseeds, chia seeds, apples and root vegetables.
Insoluble fibre
This type does not dissolve in water and is less fermentable.
Key functions:
- Adds bulk to stools
- Supports bowel regularity
- Helps prevent constipation
- Supports detoxification through efficient elimination
Sources include whole grains, nuts, seeds and vegetable skins.
Both types are essential. Soluble fibre supports the microbiome directly, while insoluble fibre ensures efficient movement through the digestive tract. Without this balance, gut function can become sluggish or disregulated (3.)
Diversity vs quantity
Many people focus on reaching a fibre target of around 30g per day. While this is a useful guide, it does not account for the type or diversity of fibre consumed.
Different fibres feed different strains of bacteria. A limited diet, even if high in fibre, can lead to a less diverse microbiome (5.)
Greater diversity in the gut is associated with:
- Improved metabolic health
- Better immune resilience
- More stable mood and stress response
This is why variety matters just as much as total intake (6.)
The 30 plants per week concept
The concept of eating 30 different plant foods per week comes from research showing that higher plant diversity is linked to a more resilient gut microbiome (4.)
Plant foods include:
- Fruit and vegetables
- Whole grains
- Legumes
- Nuts and seeds
- Herbs and spices
Each plant contains unique fibres and polyphenols, which act as fuel for different microbial species.
From a practical perspective:
- Rotate your vegetables rather than repeating the same ones daily
- Add different seeds or nuts to meals
- Include herbs and spices regularly
- Vary grains and legumes across the week
This builds diversity over time without needing to overhaul your diet.
How superfoods can help
In an ideal scenario, fibre intake comes from whole foods. However, many people struggle to meet both fibre quantity and diversity targets consistently. This is where well formulated products can be useful.
Rather than relying on a single isolated fibre, more comprehensive blends combine:
- Multiple fibre sources
- Prebiotics
- Polyphenol rich plant compounds
For example:
- Clean Greens supports overall plant diversity alongside micronutrients
- Gut Feel provides prebiotic fibres designed to feed beneficial bacteria
- Berry Biotic delivers polyphenol rich berries that work alongside fibre to support the microbiome
These can help bridge the gap when intake or variety is low, particularly in busy lifestyles.
A balanced perspective on fibre drinks
Fibre drinks can be helpful, but they should not replace a plant rich diet.
They work best when:
- Used alongside whole foods
- Formulated with a range of fibres and plant compounds
- Introduced gradually with adequate hydration
They are less helpful when:
- Based on a single fibre source
- High in added sugars or unnecessary fillers
- Used as a substitute for whole food intake
The goal is to support intake and diversity together.
Bottom line
Fibre supports far more than digestion. It plays a role in gut health, hormone balance, skin health and mental wellbeing through the gut brain axis.
A practical approach is:
- Include both soluble and insoluble fibre daily
- Prioritise diversity, not just quantity
- Aim for a wide range of plant foods across the week
- Use supportive products where needed
Consistency and variety are what support gut health over time, and play a central role in overall health optimisation.
References - (1.) Veronese, N., et al. (2025). The impact of dietary fibre consumption on human health: An umbrella review. Clinical Nutrition. https://doi.org/10.1016/j.clnu.2025.06.021
(2.) Choe U (2025). Role of dietary fibre and short-chain fatty acids in preventing neurodegenerative diseases through the gut-brain axis. Journal of Functional Foods. https://doi.org/10.1016/j.jff.2025.106870
****(3.) Bijkerk CJ et al. (2009). Soluble or insoluble fibre in irritable bowel syndrome? A randomised placebo-controlled trial. BMJ. https://doi.org/10.1136/bmj.b3154
(4.) Stanford J et al. (2025). High-diversity plant-based diet and gut microbiome, plasma metabolome, and symptoms in adults with CKD. Clinical Journal of the American Society of Nephrology. https://doi.org/10.2215/CJN.0000000682
(5.) Cantu-Jungles TM & Hamaker BR (2023). Don’t expect increased gut microbiota diversity with dietary fibre. The Journal of Nutrition. https://doi.org/10.1016/j.tjnut.2023.09.001
(6.) Alahmari LA (2024). Dietary fibre and its impact on heart health, blood sugar, weight, gut health, and inflammation. Frontiers in Nutrition. https://doi.org/10.3389/fnut.2024.1510564
(7.) Gorbach SL & Goldin BR (1987). Dietary fibre and its role in oestrogen metabolism and excretion. Journal of Reproductive Medicine. https://doi.org/10.1016/0091-7435(87)90067-3
