Feeling stressed? Your gut is likely to be involved (and fibre can help)

Mar 24, 2026

By Miriam Ferrer

Feeling stressed? Your gut is likely to be involved (and fibre can help)

Stress is often thought of as just a mental state. But anyone who's ever felt their stomach tied up in knots will instinctively know that the gut is somehow involved too.

In recent years, research has confirmed that those anxious butterflies and 'gut-wrenching' feelings happen because the gut and brain are intimately connected. In fact, they're in a constant two-way dialogue known as the 'gut-brain axis'.⁸

The gut-brain connection

Your gut is home to trillions of micro-organisms called the gut microbiome – a complex ecosystem made up of bacteria, viruses and microbes.⁵

About 150 bacteria species can dominate here, enjoying the nutrient-rich environment of the gut while carrying out essential jobs for us, such as breaking down and extracting nutrition from our food, supporting the immune system, helping to regulate blood sugar levels, and producing vital vitamins, including B vitamins.⁶

These bacteria also communicate with the brain through several pathways, including the vagus nerve – a direct line to the brainstem via the heart and lungs – using a variety of chemical messengers, such as the neurotransmitter serotonin.

The overlap between gut health and mental health

Research has found that people who suffer from mental health conditions such as anxiety and depression also often suffer from chronic bowel conditions, with fewer helpful bacteria and more that promote inflammation.²

The gut-brain axis works both ways. So while you're suffering with physical issues like bloating, stomach pain, gas, constipation or diarrhoea, the gut is also sending signals to the brain that can trigger low mood.

Stress itself can undermine the balance and diversity of your gut microbiome, allowing unhelpful bacterial species to dominate. Called gut dysbiosis, this imbalance can have major impacts on our digestive health, immunity and mental resilience.⁷

How dietary fibre helps to support your mood and fight stress

Foods rich in fibre don't just support healthy digestion; they can be fermented by helpful bacteria to produce both food for themselves and powerful support for our overall health – including our mental health.

Recent research has found that dietary fibre may help to protect against stress, anxiety and depression by nourishing helpful gut bacteria involved in mood, while suppressing harmful species.¹

Certain types of fibre – especially prebiotic fibres like fructans and GOS (galacto-oligosaccharides) – help beneficial gut bacteria to grow and thrive, particularly Bifidobacterium and Lactobacillus.

These bacteria are believed to help reduce feelings of stress and anxiety by producing neurotransmitters like GABA (gamma-aminobutyric acid), serotonin and other compounds involved in mood, relaxation and emotional balance.

How to get more fibre into your diet

The recommended daily amount of fibre is 30g a day, but 90% of adults in the UK don't eat enough, hitting a daily average of just 20g, according to the National Diet and Nutrition Survey. Foods naturally high in dietary fibre include oats, legumes, fruits, vegetables and wholegrains.

Some of that fibre will have a 'prebiotic' effect – a type of dietary fibre that the body can't digest, but that can be fermented by friendly gut bacteria like Bifidobacterium and Lactobacillus to support our health. Good sources of prebiotic fibre include:

Chicory root, leeks and Jerusalem artichokes – rich in inulin, a type of fructan
Onion, chicory, garlic, artichokes and bananas – rich in fructo-oligosaccharides (FOS), also a type of fructan
Cow's milk – for galacto-oligosaccharides (GOS), derived from lactose, the sugar in milk

However, many of us find it hard to consistently get enough fibre from diet alone, and that's where a targeted supplement can help.

PreBio Fibre+ provides a rich daily source of prebiotic fibre in the form of galacto-oligosaccharides (GOS) – complex carbohydrates that nourish helpful gut bacteria. PreBio Fibre+ contains the most researched GOS in the world, with over 100 studies carried out with both adults and children.

Nourish your gut, defend against stress

More and more people in the UK are experiencing chronic stress for various reasons, from health to finances. Our own national survey on stress revealed just how much of a toll it can take on sleep, concentration and our ability to stay calm, with impacts on both work and relationships, and young people particularly at risk.

Respondents also shared the things that helped them, including regular exercise and eating healthily. The NHS offers guidance on ways to manage stress, from exercise and breathing exercises to talking things through with a friend or therapist.

Making sure you get a regular intake of fibre – through food, supplementation or both – can also offer valuable support, nourishing both your gut health and your emotional wellbeing.

Find out more in our Ultimate Guide to Gut Health.

References