From the foods on our plates to how well we sleep, our digestive health can be influenced by more than we realise. Senior dietitian, Ciara McNulty, who works at the Women’s Health Centre at Blackrock Clinic, explains what matters when it comes to looking after our gut.

Bloating, constipation and changes in bowel habits can leave many of us wondering what is normal. With probiotics, fermented foods and the much-discussed 30-plant challenge attracting increasing attention, separating useful advice from marketing claims isn’t always straightforward.

So, what does a healthy gut actually look like, and how can we tell when something isn’t quite right?

According to Ciara McNulty, the answer isn’t the same for everyone.

“There is no core sign of a ‘healthy’ gut for all individuals as the gut microbiota – the trillions of bacteria the gut is home to – is as unique as a fingerprint,” she explains.

Bowel habits

In fact, one of the more surprising things about digestion is the wide range of bowel habits considered normal. Opening your bowels anywhere between three times a week and three times a day can be perfectly healthy, provided that pattern is normal for you. Stools should ideally be smooth, well-formed, sausage- or snake-shaped and easy to pass without straining, with no blood or mucus. Occasional bloating or gas is common, but neither should significantly interfere with everyday activities.

Persistent changes in bowel habits, blood in stools or unexplained weight loss should always be investigated by a healthcare professional.

One of the most established ways to support digestive health is through diet. Fibre is particularly important, yet many Irish adults aren’t getting enough of it.

How much fibre do you need?

Ciara says adults in Ireland are advised to eat 25g to 30g of fibre a day. A University College Cork analysis of the National Adult Nutrition Survey found that more than 80% fell short of 25g, with average intakes of around 19g. The research is more than a decade old, but the data is sound.

“People should follow a diverse diet that is rich in fibre to support gut health. It’s also important to eat regular meals throughout the day and stay hydrated,” she says.

Higher fibre intakes have also been associated with a lower risk of several chronic diseases, including heart disease, type 2 diabetes and bowel cancer.

The best way to get enough is through plant foods such as whole fruit and vegetables, wholegrains, beans, lentils, nuts and seeds. Swapping white bread, rice or pasta for wholegrain versions is a simple start, and when reading labels, look for foods with 6g or more of fibre per 100g.

Soluble fibre, found in oats, apples, beans and root vegetables, forms a gel that slows digestion and feeds beneficial gut bacteria. Insoluble fibre, found in wholegrains, nuts, seeds and fruit and vegetable skins, adds bulk to stools and helps keep things moving.

However, suddenly increasing fibre can cause uncomfortable bloating.

“When increasing your fibre intake, ensure that you do it low and slow. to give your gut time to adjust and to help reduce the likelihood of bloating or constipation,” Ciara advises.

Prebiotics are particular types of fibre that help to “feed” beneficial bacteria in the gut, including Bifidobacteria. Berries, garlic, onion and oats are good sources, and introducing them may help support gut health.

Anyone following gut-health advice online will have come across the ubiquitous recommendation to eat 30 different plant foods a week. It gained attention after research from the American Gut Project found that people eating more than 30 types weekly tended to have a more diverse gut microbiome than those eating fewer than 10.

When increasing your fibre intake, ensure that you do it low and slow. to give your gut time to adjust and to help reduce the likelihood of bloating or constipation

But common sense is required; it doesn’t mean 30 is a magic number, or that 29 plants are inadequate. What matters is variety.

“Each food provides its own nutrients, vitamins, minerals, fibres and antioxidants, so it’s important for the overall diet to stay balanced to provide the gut with a mix of fibre types and to nourish the gut,” Ciara explains.

She suggests sprinkling herbs, nuts and seeds on meals, trying a new plant food in your trolley each week and adding mixed leaves to meals for minimal preparation.

Probiotics hype?

Probiotics are another frequently mentioned must-have. Are they worth the hype?

Supermarket shelves offer everything from fermented drinks to probiotic supplements, but the evidence is more complicated.

“Fermented foods have been eaten for thousands of years and can be a good way to add live microbes to the diet,” says Ciara. “Good sources include sauerkraut, fermented milk drinks such as Yakult, miso and tempeh.”

Studies suggest the microorganisms in these foods can help diversify the gut microbiota, while fermentation can improve the availability of polyphenols, plant compounds that can help strengthen the gut barrier and support the immune system.

“Different fermented foods provide different bacteria, so variety is key,” she says. “However, not all fermented foods contain live microorganisms in the final product. Bread, including sourdough, beer and wine are made using live microbes, but processes such as heating mean they do not survive to the end product.”

A varied diet, enough fibre, regular movement and good-quality sleep are sensible starting points. Perhaps most importantly, it’s about understanding what’s normal for your own body rather than trying to achieve someone else’s idea of a perfect gut

“For most people, a varied, fibre-rich diet should be the starting point rather than supplements,” she adds.

There are, of course, other factors behind an upset stomach than just the food we eat. Anyone who has had digestive symptoms before a stressful event will know the link between digestion and emotions, while disrupted sleep can also influence digestive health. In fact, Ciara recommends seven to nine hours of good-quality sleep a night. Poor sleep can affect our circadian rhythm, which may in turn influence the gut microbiota.

“Stress can trigger a chain reaction in the body, including the production of the stress hormone cortisol,” she explains. “This can cause a disruption to the communication pathways between the gut and the brain, known as the gut-brain axis.”

To help manage stress, she suggests approaches such as breathwork, meditation, and reducing screen time.

“Looking after your digestive health doesn’t have to mean following every new food trend or buying expensive products,” she says.

“A varied diet, enough fibre, regular movement and good-quality sleep are sensible starting points. Perhaps most importantly, it’s about understanding what’s normal for your own body rather than trying to achieve someone else’s idea of a perfect gut.”