Fibre - the most powerful nutrient you’re not eating enough of
- Gemma Westfold
- Sep 19, 2025
- 4 min read
I love fibre. I don't care if it's not popular, I don't care if people don't talk about it at dinner parties. Fibre is the cornerstone of all facets of health, not just gut health. It should be colourful and delicious. Ditch the bran cereal.
Fibre does not get the attention it deserves. Protein, “eating clean” (eye roll), or taking the latest supplement might look appealing, but none of it matters if you have not nailed the basics. What is on your plate is the driver of health, and the clearest way to see this is with fibre. It is the real longevity nutrient. No supplement will ever be this powerful.
Most people think of fibre as boring, a cure for constipation, or something in bran flakes. No wonder it gets ignored. But the truth is that fibre is one of the most powerful tools we have for health. It feeds your gut microbes, who in turn make compounds that protect and nourish you. Without fibre, they starve. When they starve, your health suffers. And it is so very easy and accessible for us all.
The landmark meta-analysis Carbohydrate quality and human health: a series of systematic reviews and meta-analyses showed clearly that people who eat the most fibre live longer and have lower risks of heart disease, type 2 diabetes, and several cancers. Yet in the UK, the recommendation is 30g per day and the average intake is only about 18g. Clinically, I see clients who eat far less. That gap is costing us.
Why fibre matters: short chain fatty acids
When your microbes ferment fibre, they produce short chain fatty acids (SCFAs): butyrate, acetate and propionate. These are only made when you eat enough fibre. You cannot supplement your way to the same effect. SCFAs are one of the most important anti-inflammatory agents your body has access to, and they are produced right there in your colon every day if you feed your microbes properly.
Here is what SCFAs do:
Butyrate is the primary fuel for the cells lining your colon, keeping them healthy and tightly sealed. That prevents “leaky gut” where toxins and microbes slip into the bloodstream and trigger inflammation. Butyrate also helps regulate gene expression, supporting anti-cancer pathways and calming inflammatory ones.
Acetate travels through the bloodstream, influencing appetite regulation, cholesterol metabolism, and immune function. It can even cross into the brain, where it influences signalling that helps manage food intake.
Propionate is taken up by the liver, where it helps control glucose production and cholesterol synthesis. It has been shown to reduce insulin resistance and support healthy blood sugar balance.
Together, SCFAs train the immune system, calm overactive inflammatory responses, reduce levels of inflammatory cytokines, and support healthy communication between the gut and the rest of the body. They also influence hormones that regulate appetite and weight, protect against heart disease, support brain health, and even help maintain bone density.
Without enough fibre, SCFA levels drop. That means higher inflammation, weaker gut barrier, worse blood sugar control, and increased risk of chronic disease.
Fibre and hormones
Fibre is particularly important during perimenopause when oestrogen levels are fluctuating. Soluble fibre binds excess oestrogens in the gut and encourages excretion, taking pressure off the liver. This helps smooth out some of the hormonal swings that contribute to symptoms. A healthy microbiome, fuelled by diverse fibres, also supports the “estrobolome,” the group of gut microbes that influence how oestrogens are metabolised. SCFAs reduce the inflammation that rises as oestrogen falls, protecting against hot flushes, bone loss, weight gain and cardiovascular risk.
Fibre for skin, immunity and metabolism
Fibre influences almost every system. SCFAs travel throughout the body reducing inflammation, which benefits skin health, joint health, and cardiovascular function. Fibre supports a balanced immune system so you can defend against infection without tipping into allergy or autoimmunity. Fibre-rich meals slow digestion, smooth blood sugar responses, and lower cholesterol, reducing risk of diabetes and heart disease. And yes, it keeps digestion regular, ensuring you clear waste efficiently with a decent daily bowel movement.
What kind of fibre?
Fibre is not one thing. Different types have different roles:
Soluble fibre dissolves in water to form gels, slows digestion, lowers cholesterol, and feeds microbes. Found in oats, apples, beans, lentils.
Insoluble fibre adds bulk, speeds transit, and helps prevent constipation. Found in whole grains, nuts, seeds, vegetables.
Resistant starch resists digestion in the small intestine and ferments in the colon, producing SCFAs. Found in beans, lentils, cooled cooked potatoes or rice, green bananas.
You need all of these, from a wide variety of colourful plant foods, to feed different microbes and maximise SCFA production.
What foods give you fibre?
Forget the idea that fibre is bland. It is colourful, delicious, and in everyday foods. Here are some examples, with approximate fibre values from UK food composition data:
Half an avocado (about 68g flesh) provides around 4.6g fibre
100g raspberries contain about 6.5g
100g strawberries give about 3.8g
A medium apple offers about 2.5 to 3g
150g cooked lentils provides 6 to 7g
25 g almonds give about 4 to 5g
180g baked potato with skin has about 5 to 6g
A slice of wholemeal bread adds around 2 to 3g
80g green peas give about 2 to 3g
50g porridge oats deliver about 4g
If you build meals around these, it is easy to reach 30g a day.
The bottom line
Fibre is not glamorous, but it is the foundation. Without enough, your microbes cannot make the SCFAs that keep you healthy. Supplements have their place, but you cannot out-supplement a poor diet. If you want longevity, smooth hormones, strong immunity, good skin, and the energy to enjoy life, start with fibre. Think at every meal: where is the fibre? Get that right, and the rest can fall into place. Need a little help, or perhaps you have gut issues that make you limit fibre - let's talk.
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