Authors: Dr Veronique Chachay and Ms Abigail Marsh
What is inflammatory bowel disease?
Inflammatory bowel disease (IBD) is an umbrella term referring to chronic diseases of the gastrointestinal tract (gut). These include ulcerative colitis (UC) and Crohn’s disease (CD). IBD is currently not curable. It comes with a number of debilitating symptoms including abdominal pain, cramping and diarrhoea.
Approximately 75,000 Australians are living with IBD, with over 1622 new cases diagnosed every year. Nutrition is crucial in the management of IBD. It is often the primary strategy changed by patients to minimise gastrointestinal distress. Yet, dietitians and other health professionals lack evidence-based nutrition guidance to help patients in managing their symptoms, due to poor uniformity in research results.
Should I cut out fibre if I have IBD?
People with IBD tend to exclude foods that are rich in fibre, because of the belief that fibre makes their symptoms worse. There is no evidence that this is the case. In fact, the opposite is true – cutting out fibre is likely to reduce “food” for the gut microbiota. These microorganisms (“gut bacteria”) that live in our gastrointestinal tract (gut) thrive on the roughage found in whole grains, fruit, and vegetables. Eating a variety of fibres from whole foods promotes microorganism community’s growth and diversity, which supports good health outcomes.
What is the link between the fibre I eat and my gut bacteria?
Early research findings suggest that IBD is associated with unfavourable variations in gut microbiota communities, when compared with people without IBD. When someone has a healthy balance of gut bacteria, they have a protective intact (unbroken/ undamaged) “mucous layer” that lines their gut. This helps to stop the mucosa becoming inflamed. Also, as a person’s gut bacteria “feeds” on fibre, it gives off molecules called short chain fatty acids (SCFA), that are beneficial for gut mucosa health.
Evidence from experimental studies in humans shows that a diet low in “plant products” (therefore of fibre) for as little as 5 days, promotes the growth of bacterial communities that digest protein and fat from food. When there is an imbalance - less fibre, but more fat and protein, the less healthy bacteria make unhealthy molecules associated with inflammation, cardiovascular disease, and type 2 diabetes rather than the healthy SCFA that fibre digestion makes. So, if patients with IBD limit fibre-rich foods in their diet, this may make their disease worse over time by cutting down the population of protective bacteria and the production of beneficial SCFA.
Are there any ‘low inflammation’ eating patterns that support gut health?
In addition to being fibre-rich, wholegrains, fruit and vegetables are also rich sources of vitamins, minerals, and phytonutrients. These are all part of the body’s antioxidant and anti-inflammatory defence systems.
Early research findings suggest that following an anti-inflammatory dietary pattern may be associated with reduced risk of, and improvement in disease severity and patient-reported symptoms in IBD. The Traditional Mediterranean Diet (TMD) is well recognised for its anti-inflammatory properties, and beneficial outcomes on gut microbiota diversity.
The TMD is the diet followed in countries around the Mediterranean Sea, and thus varies according to crops and produce available locally. The diet is commonly rich in freshly prepared seasonal vegetables, fruit, wholegrains, olive oil, and contains small amounts of seafood, dairy, and unprocessed meat. It is the combination of the nutrient density (vitamins, minerals, and phytonutrients), the monounsaturated fat in olive oil, the fibre in fresh produce, and the lack of processed foods with additives, that confers the overall anti-inflammatory and antioxidant effect.
This dietary pattern has gained a lot of attention over the last 10 years, especially in the context of chronic diseases where systemic inflammation is a key driver. Whilst the specific food products found and produced around the Mediterranean Sea may not be found everywhere in the world, the overall principles of the TMD can be duplicated with locally available products.
Have you heard about the local clinical research trial into IBD and the Traditional Mediterranean Diet?
The effects of the TMD principles on markers of inflammation and disease severity of IBD have thus far not been explored. This is why we are currently conducting a clinical trial (IBD-MAID) at the Royal Brisbane and Women’s Hospital (RBWH), Queensland Institute of medical Research (QIMR) and The University of Queensland (UQ). The trial is investigating the effects of a modified TMD diet, to suit the Australian context, on disease severity, patient reported outcomes, and quality of life in individuals with IBD. The trial is currently recruiting.
For further information, please contact PhD candidate and Accredited Practising Dietitian Abi: abigail.marsh@uq.net.au
