How dietary fibres impact our gut bacteria and influence our health
We have known for ages that dietary fibre is good for our health, however many people do not eat enough fibre. Fibre keeps our digestive system healthy and helps to prevent constipation. In addition, a diet high in fibre can reduce the risk of cardiovascular diseases and colorectal cancer. The other way around, a typical Western diet, which is rich in saturated fats and simple carbohydrates but depleted of dietary fibre, has been associated with obesity and metabolic disease. How are our gut bacteria involved in the beneficial effects of fibre?
Dietary fibre (plant-based carbohydrates that, unlike other carbohydrates (such as sugars and simple starches), are indigestible for us humans, but not for the bacteria living in our intestines. Some bacteria in our gut possess the enzymes necessary to break down fibre into smaller fragments which can be absorbed by our bodies or are used by other bacteria to feed on.
A lot of research is being conducted on how fibre mediates the beneficial effects on our (gut) health. Two studies recently published in Cell Host & Microbe looked in more detail into how fibre influences the microbial populations and mucus layer in the gut. In one experiment the researchers found that when mice were put on a high-fat, low-fibre diet, the amount of bacterial species measured in faecal samples drastically decreased a tenfold. In another experiment, they changed the mouse’s diet from a high-fibre diet to a low-fibre diet. This time the researches focused on the type of species present in the faeces and noticed common species to become rare and rare species to become common. When the mice were put on a high-fat diet and the prebiotic fibre inulin was given additionally, the researchers saw, despite the high-fat diet, that the mice had healthier bacteria in their gut and the mucus layer of the gut was in better condition, indicating an improved barrier function.
Prebiotics are non-digestible, fermentable food ingredients, defined as “selectively fermented ingredients that allow specific changes, both in the composition and/or activity of the gastro-intestinal microflora that confer benefits upon host well-being and health”.
Although all prebiotics are fibre, not all fibre is prebiotic. A food ingredient can be called a prebiotic if it is not digested in the upper GI-tract, not fermented by the intestinal microflora and selectively stimulates the growth/and or activity on intestinal bacteria potentially associated with health and well-being.
The researchers concluded that fibre is good for maintaining the intestinal barrier and preventing a state of low-grade inflammation. A low-fibre diet can trigger not only inflammation in the gut but also throughout the entire body, thereby affecting health at distant places. A diet high in fibre could support the treatment of immune mediated diseases such as irritable bowel disease, the authors suggest. However, adding one type of fibre to your diet won't be the remedy to cure diseases associated with a Western diet. Since not all bacteria are the same, one can imagine that different bacteria have their own preferences in relation to the carbohydrate composition that they can use for growth. That is why Winclove’s probiotic formulations contain strain-specific prebiotics. We have screened every probiotic strain for their favourite carbohydrates, and know which prebiotic compound is preferred by each individual strain.
Just as eating a varied diet rich in different types of fibre is good for the commensal bacteria in your gut, adding a mixture of prebiotics to a probiotic formulation is good for the health of probiotic bacteria in the probiotic product. Providing them both with healthy fibres means our intestines and immune systems remain in good working order.
References: Zou J, Chassaing B, Singh V et al. Fiber-Mediated Nourishment of Gut Microbiota Protects against Diet-Induced Obesity by Restoring IL-22-Mediated Colonic Health. Cell Host & Microbe. 2018;23(1), 41-53.
Schroeder B.O., Birchenough G.M.H., Ståhlman M. et al. Cell Host Microbe. Bifidobacteria or Fiber Protects against Diet-Induced Microbiota-Mediated Colonic Mucus Deterioration. 2018;23(1):27-40.
Klik op het menu voor inhoud en andere functies.
Gebruik de pijlen aan de zijkant om door het magazine te bladeren.