The benefits of a gut healthy, fibre-rich diet for the long term

Girl eating avocado

We are what we eat. Everything that makes up our body and the energy it needs to function comes from what we consume. This means that if you make a conscious effort to eat as well as possible, you’re on the right track for good health. Those foods that are high in salt and sugar, as well as alcohol, are best kept for special occasions – not enjoyed every day.

As you will become aware during this challenge, the gastrointestinal (GI) tract or gut is where the body breaks down and absorbs the nutrients it requires, and fibre is crucial in making sure the gut environment (microbes) is well fed and protected. If the gut functions well, the entire body benefits. However, the body requires a wide range of nutrients to be healthy, and the gut can’t extract those nutrients if they’re not in our food. That’s why we need to continually eat a balanced diet to ensure an optimal supply of nutrients – for the benefit of our gut and our body.  

Why eating for gut health is so important

Your gut lining is the barrier between food, toxins and microbes on one side, and the rest of the body on the other. This barrier needs to be maintained to protect our tissues and prevent infection and inflammation. Good food hygiene practices can help prevent pathogenic bacteria from entering the gut and causing diarrhoea and other symptoms of food poisoning. A healthy balanced diet also helps maintain the gut barrier function. The continual consumption of a poor diet, such as western-style diets characterised by high fat and protein levels but lacking in dietary fibre, often leads to a breakdown of gut barrier integrity.

A so-called leaky gut can result in persistent low-level inflammation as the immune system works against microbes breaching the barrier.

Gut discomfort in the form of bloating, excess gas production, constipation and pain, can seriously affect your quality of life. Maintaining a diet that includes a diversity of fibre-rich foods will promote good gut function and help reduce gut discomfort. However, too much fibre can also cause discomfort, especially if dietary levels increase sharply.

Prioritising long-term health

One of the most important reasons for maintaining a lifelong gut-healthy diet – especially a fibre-sufficient diet – is to protect against colorectal cancer (CRC). While many factors contribute to CRC, diet plays a critical role and lack of dietary fibre is the single biggest risk factor. CRC can take decades to develop, a process generally assisted by less-than-ideal diets and lifestyles. Dietary fibre helps to reduce the impact of toxins we are regularly exposed to that can damage the gut tissues, including their DNA, and which can contribute to CRC. Dietary fibre does this by diluting toxins via increasing the digested food bulk and by promoting regular movement along the gut. Another important feature of many fibres is their ability to be fermented by gut bacteria, especially in the colon. This results in the production of substances needed by the colonic tissues, and which maintain their health.

Finally, the long-term consumption of a variety of foods, particularly those high in dietary fibres, will help maintain a vibrant and diverse population of beneficial bacteria within the large bowel. Benefits include bacterial production of a wide range of compounds that promote the health of the gut, other bodily tissues and the immune system, as well as a greater capacity to prevent the growth of pathogenic bacteria. For this reason, there’s no harm in continuing with the high-fibre diet you’re sticking to now. In fact, it’s highly recommended for the health of your gut today and your long-term health in the future.


Dr Pennie TaylorThis article was written by Dr Pennie Taylor

Dr Pennie Taylor is a research scientist and clinical dietitian at CSIRO Health and Biosecurity Business Unit in the Food and Nutrition Program. Dr Taylor holds a PhD through the University of Adelaide School of Medicine, exploring dietary strategies to optimise glucose variability and self-management behaviour using Real-Time Continuous Glucose Monitoring. Her research focuses on how digital health technologies and dietary patterns can support weight management, chronic and clinical disease (gut health and diabetes) and weight loss surgery, in health and community environments. Dr Taylor has over 15 years’ experience in clinical practice and nutrition research. At CSIRO, her diverse skills cover delivery and development of large complex clinical and community trials that explore the influence of food components and dietary composition on health outcomes. Dr Taylor extends these skills working with industry partners to design and develop food and nutrition solutions for community programs that are currently active in the Australian community. Her capacity to develop and translate scientific research outcomes into nutrition and health programs and products is strengthened by her clinical experience and practice knowledge. With over a decade of clinical and medical dietetics, acting as an allied health practitioner has complimented her science. Dr Taylor’s experience has led to several commercial and scientific outcomes. These include working with commercial and industry partners to develop community and digital lifestyle programs, and the development of evidence-based marketing statements. She is also the co-author of the CSIRO Healthy Gut and CSIRO Low Carb Diet Book series, which was recently translated into ready meals designed to comply with the CSIRO Low Carb diet.