Fibre; why is it so important?
Fibre and its health benefits
There are a range of health benefits associated with fibre, including reduced cholesterol, healthy bowel movements, a reduced risk of colon cancer, and optimised fertility. Our bodies don’t have the ability to break down fibre effectively by ourselves; we need help, and that is where our gut microbes come in.
The breakdown products of the fibre we eat are called short chain fatty acids (SCFA’s), and there are three main groups: acetate, propionate, and butyrate. Every time we eat fibre, our microbes help us to produce these in varying amounts depending on the time of fibre we eat. In order to reap the full health benefits, it is important to eat as diverse a plant based diet as possible. SCFA’s exert a number of effects on the bowel; first, they make the large intestine (the colon) more acidic and this prevents the growth of inflammatory bacteria. They also suppress the growth of health damaging strains of bacteria such as E-coli. The more fibre we eat, the more SCFA’s are produced and the more anti-inflammatory the gut environment becomes. In contrast, if we don’t eat enough fibre, we provide our microbes with less food and SCFA production is decreased, thereby creating a less healthy gut environment with reduced diversity.
Inflammatory bowel disease and the role of fibre
Although IBD has many causes, diet is recognised as a factor, particularly in crohn’s disease. With a low fibre diet low, bacterial diversity is reduced, there is a reduction in the SCFA, butyrate, and there is an overgrowth of inflammatory bacteria, particularly E.coli. This results in an inflammatory cascade, with further dysbiosis (imablance in the gut microbiome) and production of more E.coli. This affects the tight junctions in the gut and eventually leads to increased intestinal permeability (leaky gut) which allows the E.coli to invade the intestinal wall. This activates the immune system to attack the invading bacteria and results in inflammatory bowel. Fascinatingly, butyrate may actually repair leaky gut, and along with the other SCFA’s, produce anti-inflammatory gut bacteria. This results in reduced gut inflammatory markers which then helps to prevent autoimmune disease by communicating directly with our T cells, part of our immune system, to not attack the body’s own cells.
So, could fibre prevent IBD?
So, could a plant-based diet with sufficient fibre play a role in the prevention of IBD and also in the management? Well, it is important to state that there are other known risk factors involved, including genetics and smoking (for Crohn’s cases), but it appears to be of significant importance to create and maintain a healthy and diverse gut microbiome, both in terms of prevention and treatment. The only way to achieve this is by increasing the number of plant foods in your diet, thereby creating diversity, and reducing the number of foods associated with a less diverse, inflammatory gut environment.
We recommend working with a professional if you are trying to increase your fibre intake and have a digestive disorder. Our dietitian Lisa Simon has a wealth of knowledge and expertise in the subject – book an online appointment with her today to find out more.
Bulsiewicz, W (2020). Fiber Fueled. Penguin Random House: USA
Khan. I, Ullah, N et al (2019). Alterations of gut microbiota in inflammatory bowel disease (IBD): Cause or consequence? IBD treatment targeting the gut microbiome. Pathogens 8(3):126
Ni.J, Shen. T.C, Chen. E, Z et al (2015). A role for bacterial urease in gut dysbiosis and Crohn’s disease. Science Translational Medicine. 9(416)
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