Gluten, a storage protein commonly found in wheat, rye, and barley, can specifically be found forming in the endosperm of seeds from these grains. Glutamine and proline, the core amino acids making up this specific storage protein, are where the main digestion problems in individuals with Celiac disease reside. These together are classified as prolamins. A variety of different proteins make up gluten, which is why it is defined as a storage protein. Two of the main groups of the prolamin fractions are glutenins and gliadins; one of the main differences between these refers to the insolubility and solubility in alcohol, respectively. Each individual grain containing gluten consists of a specific sequence of amino acid chains, which helps to further define these specific grains. Gliadin specifically is a very packed and dense protein, which makes it difficult for the enzymes to attack and break it down.
The normal ingestion of gluten is a tough digestive process in all humans because the amino acids making up gluten do not easily break apart as they travel through the digestive system. In other terms, the proteins found in gluten can commonly be resistant to most of the enzymes found in the digestive system, which proves why the breakdown is indeed difficult. Enzymes are one of the most powerful sources in the digestive system that act as catalysts to help breakdown particles, specifically splitting up proteins into their building blocks, amino acids. Enzymes, therefore, also work to speed up the chemical reactions that occur throughout the entire body. When properly working, the enzymes strive to break down the proteins into the specific groups of amino acid sequences called peptides. They are normally secreted in many different parts of the digestive system including the stomach, pancreas, and small intestine.
Gluten becomes even more resistant to the enzymes in individuals that have Celiac disease or even a slight gluten sensitivity. In individuals with Celiac disease, the immune system sees gluten as a foreign invader and thus begins to attack the protein, specifically gliadin, by triggering a T-cell response, as soon as it reaches the walls of the small intestine. This specific type of response by the immune system, an autoimmune response, results in large inflammation occurring throughout the entire system. The inflammation results from the attacking of the healthy villi lining the walls of the small intestines. Villi are very small, finger-like projections that aid in the digestive process by both secreting the digestive enzymes necessary for breakdown as well as absorbing the nutrients found in the different foods consumed. When the body does not recognize those villi as being its self, less nutrients are soaked up and a smaller amount of digestive enzymes are produced, thus resulting in the digestive problems occurring in individuals with Celiac disease. Not only does the body begin attacking itself, but over time oligopeptides derive from the high protein content still found in the body due to an inability to be broken down into di- or tri-amino acids. These long-chain polypeptides build up in the small intestine and can result in cell clumping, new arrangement of actin filaments, and eventually cell death. All of these problems can occur in the small intestines and other digestive organisms of individuals with Celiac disease and thus can lead to symptoms of Celiac disease including stomach pain, gas, and bloating due to the inflammation that occurs.
Digestion gluten | Nutrition. (n.d.). Retrieved October 21, 2016, from http://www.drschaer-institute.com/us/nutrition/digestion-gluten-1105.html
Enzymes — How Cells Work | HowStuffWorks. (n.d.). Retrieved October 21, 2016, from http://science.howstuffworks.com/life/cellular-microscopic/cell2.htm
Getting out the gluten — Harvard Health. (n.d.). Retrieved October 21, 2016, from http://www.health.harvard.edu/family-health-guide/getting-out-the-gluten
How is Gluten Digested? | Food Understood. (n.d.). Retrieved October 21, 2016, from https://foodunderstood.com/2013/04/09/how-is-gluten-digested/
Understanding Gluten and How to Digest It — Dr. Douillard … (n.d.). Retrieved October 21, 2016, from http://lifespa.com/understanding-gluten-digest/
What is gluten? What is gliadin? — Celiac.com. (n.d.). Retrieved October 21, 2016, from http://www.celiac.com/articles/8/1/What-is-gluten-What-is-gliadin/Page1.html