The colour, taste, aroma and appearance make artificially flavoured snacks a hearty choice. World Health Organization allows the use of food additives to improve these properties, but recent research shows that additives that are mixed with food to make them tastier and crispier, or just to enhance their shelf-life, can take away your health. Though food additives are generally considered to be safe, recent research shows that there is a link between certain food additives and the increased prevalence of coeliac disease, a rare kind of auto-immune disease.
Coeliac disease revolves around a group of proteins called gluten found in cereals like wheat, as well as in grains such as barley and rye. Gluten is normally harmless, but for certain genetically predisposed groups of people with some specific mutations in an important immunity-related gene called HLA-DQ, it can cause some deleterious effects. For such people, if gluten is ingested, there will be an abnormal immunological response. This can lead to the production of different types of autoantibodies which can eventually damage a number of organs. In the small intestine, gluten causes an inflammatory reaction and may produce the shortening of the villi lining, also called villous atrophy. This can affect the absorption of nutrients and may lead to malnutrition and anaemia. If coeliac disease is not identified at an early stage and left untreated, it can develop into cancers such as intestinal lymphoma. The only known effective treatment for coeliac disease is strictly following a lifelong gluten-free diet.
The additives angle
Coeliac disease is rare: Only one in 100 people are affected by it worldwide. However, recent research shows that there is an increase in the prevalence of the disease. Changed food habits, addiction to fast-food and processed food, etc., are thought to be the reasons behind this. Evidence suggests that certain food additives can trigger autoimmune reactions in the body, which can lead to coeliac disease. This is because certain food additives are in the form of metal nanoparticles that can trigger an immune response, which in turn makes the intestinal walls more active and responsive to gluten. This can increase the risk of coeliac disease, especially in genetically predisposed individuals. The molecular mechanism behind this linking can be summarised as follows: Impairment of the intestinal barrier may cause gluten peptides to permeate the sub-mucosa and cause coeliac disease. They can also affect the intestinal microbiota which can also lead to the disease. However, further studies are needed to prove this link. Other autoimmune disorders also will be the result.
Microbial transglutaminase (mTGs) is a food additive commonly used to increase food-products’ juiciness, water retention capacity, emulsifying properties, stability, and elasticity. It is a bacterial enzyme heavily used in industrial processing of meat, dairy, baked and other food products. Microbial transglutaminase can glue together proteins, and is used to improve food texture, palatability and shelf-life. This enzyme functions similarly to the transglutaminase produced by our body, which is known to be the target of autoimmunity in coeliac disease. Our normal gut fauna could also produce microbial transglutaminase and in this way, the amount of this enzyme will be significantly increased when the microbial population in the gut is altered by factors like infection, antibiotics or stress or through consumption of industrially processed foods.
The peptides resulting from the fragmentation of the gluten protein are highly susceptible to transglutaminase, which modifies them to make a variety of new peptides. These unusual peptides are resistant to further breakdown, and they will be recognized as foreign bodies by the immune receptors produced inside the gut wall by the HLA-DQ gene. However, this happens only in those individuals carrying the HLA-DQ gene variants which can develop into coeliac disease. Aggravating this, components of gluten also loosen the connections in the cell lining of the gut, allowing more gluten-derived proteins as well as microbial transglutaminase to interact with immune cells. Microbial transglutaminase itself could also increase intestinal permeability by directly modifying proteins that hold together the intestinal barrier. But in order to probe into deeper details, further research using animal models are needed, according to a study published in Frontiers in Pediatrics.