Our gastrointestinal (GI) tract is an amazing organ system. It can digest food to provide us nutrients, but somehow does not digest itself. In fact, the stomach, one of the key organs of the GI tract, can handle relatively strong hydrochloric acid without sustaining any damage. All this is possible because of a key defence line – mucous.
What is mucous and what does it do?
Mucous is a thick slimy fluid largely made up of water (90-95 per cent), electrolytes, lipids (1-2 per cent) and proteins (especially mucin), that is produced by salivary glands in the mouth, epithelial cells in the stomach and goblet cells in the small and large intestines. On average we produce around 10 litres of mucous a day, and it’s a continuous process.
Its job includes acting as a lubricant to facilitate the movement of food from the mouth into the GI tract and stool out of it. It protects the intestines against mechanical, chemical, and biological attacks by coating its cells. It operates as a surface cleaner, removing debris and bacteria, yet allowing nutrients and water to readily diffuse through it for absorption.
“In the stomach, mucous prevents the formation of ulcers and protects it against injury. When you go down into the intestine, the mucous layer has a protective effect on the intestinal enterocytes,” says Dr Raj Vigna Venugopal, a gastroenterologist and hepatologist at Manipal Hospital, Bengaluru.
But it does so much more than protect the gut. The interaction of the billions of bacteria in our guts, collectively referred to as the Gut Microbiota, is facilitated by the mucous layer. It provides these microscopic organisms with nutrients and acts as an attachment site for some.
“If you look at the good bacteria (in our gut), they convert the dietary fibre into short chain fatty acids (SCFA) that are a big nutritional element for the enterocytes (intestinal absorption cells). And they are very essential for maintaining the integrity of the cells and the tight junctions (space between cells),” adds Dr Venugopal.
But just like most things in our body, our dietary habits, gut microbiota, and pathogens play a major role in changing the synthesis, composition, penetrability, and degradation of this mucous layer.
Things that damage your gut mucous lining
There may be several reasons why the gut’s mucous lining degrades, be it an infection, bad lifestyle choices or an underlying health condition. Most research in this area points to a Western diet that is high in fat and carbohydrates, and low in fibre as being bad for the gut and its mucous lining.
This happens due to the decrease in the expression of genes such as cftr and decreased production of enzymes such as fatty acid synthase which decrease the thickness and viscosity of the mucous layer. There is also impairment in the mucous production by goblet cells and an increase in the population of mucous disrupting bacteria.
Degradation of the mucous lining allows cohabiting and disease-causing microorganisms to reach the intestinal lining, thereby leading to infection and inflammation. Alterations in the mucous layer is also observed in diseases such as inflammatory bowel disease, cystic fibrosis, ulcerative colitis, colorectal cancer, amoebiasis, cholera, celiac disease, and even food allergies.
“There is reduction in the thickness of mucous in the celiac disease due to damage to epithelial cells in intestine,” says Dr Govind Makharia, professor, department of gastroenterology, All India Institute of Medical Sciences, New Delhi.
Read More: Why your gut may not be getting along with gluten
Read More: Inflammatory bowel disease: Symptoms, causes, diagnosis and treatment
A healthy gut mucous layer
While there are several reasons why our gut’s mucous lining could get damaged, research shows that we can promote the development of a healthy layer of mucous in your gut by following good lifestyle practices. These include eating healthy, consuming lesser alcohol and caffeine, exercising, and taking probiotics.
A lot of research shows that following a Mediterranean diet can help maintain a healthy gut mucous layer, but experts suggest eating diverse foods including fruits, vegetables, whole grains, legumes, and nuts should have the same effect.
One can also promote mucous production in the gut by eating fibre as intestinal cells utilise the short chain fatty acids produced by gut bacteria as an energy source. The fibre in our diets is among the main sources of food for our gut bacteria.
Other lifestyle changes should include reducing tobacco intake and drinking sufficient water, while it is essential to also maintain good mental health and a healthy body weight.
