Fibre, your gut's favourite food

We often think of fibre as something that keeps us regular but fibre does so much more than help you go to the loo. There are many different types of dietary fibre, and they come from a huge variety of plant foods.

Yet when someone says “I need to eat more fibre”, many of us immediately think of bran, brown bread or a bowl of All-Bran first thing in the morning. Whilst these can contribute fibre to the diet, fibre is so much more interesting than that.

What exactly is fibre?

Fibre is found naturally in plant foods and isn't completely broken down and absorbed in the small intestine. This means it can reach the large intestine, where different types of fibre have different effects. Some fibres absorb water and can help produce a softer, well-formed stool. Others add bulk and can help stimulate movement through the digestive tract. And then there are fibres that are fermented by our gut microbes. This is where things get really interesting. Fibre feeds your gut bacteria.

They use components of the food we eat, particularly certain types of fibre as fuel. When they ferment these fibres, they produce compounds called short-chain fatty acids, including acetate, propionate and butyrate. These compounds have important roles within the gut and are one of the reasons that feeding your microbiome is such an important part of gut health. So when you eat fibre, you're not just feeding yourself , you're feeding your gut ecosystem too. Variety is the secret and this is where I think we often get fibre wrong. It's not simply about eating more of the same fibre, it's about eating different types of fibre from lots of different plant foods. Vegetables, fruit, wholegrains, beans and pulses, nuts and seeds all provide different types of fibre as well as other plant compounds.

So if you eat exactly the same high-fibre foods every day, you're not necessarily providing your microbiome with the variety it needs. Think variety rather than volume.

This is one reason I love the idea of challenging yourself to eat 30 different plant foods a week and herbs, spices, nuts and seeds count!

A healthy, varied diet rich in plant foods provides much more than fibre. It gives us vitamins, minerals, polyphenols and other beneficial plant compounds, whilst also supporting our gut microbiome. Maintaining good gut health is part of the bigger picture of healthy ageing.

We want to support our: Digestive health Metabolic health Immune function Brain health Heart health Muscle and bone health Overall resilience

Fibre is therefore not simply about avoiding constipation, it's one of the foundations of a diet that supports health for the long term.

But what if fibre makes you bloated? This is where it gets a little more complicated. If you have a healthy digestive system, increasing the variety of plant foods in your diet is generally a great thing but if you already have IBS or another digestive problem, suddenly going from very little fibre to eating huge amounts of beans, lentils, wholegrains and vegetables can leave you feeling considerably worse!

Your gut needs time to adapt.

And some types of fibre may be much better tolerated than others depending on your individual digestive system.

This is why my approach isn't simply “Eat more fibre", it's “let's work out which fibres your gut can tolerate, and gradually build from there.”

That's where my four-step approach comes in.

CONSIDER What's happening in your gut and what might be contributing to your symptoms?

ADD IN Rather than simply taking foods away, we gradually introduce a wider variety of foods to support microbial diversity.

REPLENISH & NOURISH We make sure you're getting the nutrients and functional foods your body and gut need.

BALANCE We look at the other things that influence your gut — particularly stress, sleep and movement. So how much fibre do you need?

In the UK, the general recommendation for adults is around 30g of fibre a day, but I don't want you obsessing over hitting a particular number. I'd much rather you focus on variety. Try adding another vegetable, eating seasonally is good for this. Sprinkle some seeds onto your breakfast. Have a handful of nuts with your morning coffee. Swap between different wholegrains. Include beans or lentils if you can tolerate them (again start slowly).

Eat different fruits. Use herbs and spices. Small changes add up.

And if your gut is currently sensitive, increase fibre gradually rather than suddenly doubling your intake. Think of it like going to the gym - you wouldn't pick up the heaviest weight when you start out because you would really hurt the next day! You work up to lifting heavy weights.

Your perfect poo isn't the only goal!

Yes, fibre can help keep your bowel movements regular but that's only part of the story. Fibre is also food for your gut microbes.

And when you eat a wide variety of plant foods, you're not just helping your digestive system today, you're supporting the ecosystem that plays an important role in your health over the longer term.

So next time you're thinking about fibre, don't just think, “Will this help me poo?” think, "what am I feeding my gut bacteria?”

Because healthy ageing starts in the gut.