Gluten-free foods are almost everywhere, and for a good reason – around 1% of the world population suffer from celiac disease and cannot eat gluten. What happens in the body when gluten is eaten, and why does it lead to symptoms like diarrhea, malnutrition, or even anemia? Watch this episode of Medicurio to find out!
EXTRA INFORMATION ABOUT CELIAC DISEASE
*Are oats safe for celiac patients to eat?*
Most people with celiac disease can tolerate avenins, the gluten protein found in oats. However, they should still be cautious because oats may be contaminated with gluten proteins from wheat/barley/rye, as these grains are often processed in the same factory. Discuss with a dietician or physician when deciding if oats should be included in a gluten-free diet.
*What kinds of food contain gluten?*
The Celiac Disease Foundation has a list here: http://bit.ly/1DtfMdL
*Why are antibodies against gluten and tissue transglutaminase produced?*
B cells have unique B cell receptors (BCR). Whatever the BCR can bind to, the antibodies this B cell produces will bind to. When a protein binds to a particular B cell’s BCR, it gets internalized, broken down into small peptides, and presented on MHC class II proteins on the surface. If an activated helper T cell can bind to the B cell’s MHC class II protein using their TCR, they can activate the B cell. The B cell then starts producing antibodies against the protein that was internalized.
For gluten peptides, the B cell internalizes these peptides and presents them to T cells, which will recognize them with their TCR since they were activated by dendritic cells earlier with the same peptide. The B cell then produces antibodies against the gluten peptides.
For tissue transglutaminase (tTG), since tTG needs to bind to gluten peptides to modify them, they often exist as one protein complex. B cells that have BCRs that can bind to tTG will internalize a complex with both tTG and gluten peptides. When they break that complex down into smaller peptides, the B cell will present both fragments of tTG and gluten peptides on their MHC class II protein. Activated helper T cells will recognize gluten peptides and activate this B cell, but this B cell will produce antibodies that are against tTG since its BCR could bind to tTG.
*What are the rates of HLA-DQ2 or 8 in the world? What about for celiac disease?*
Look up your country in this link for HLA-DQ2 or 8 rates: http://bit.ly/2rRhGVJ
The World Gastroenterology Organisation also has a list of celiac disease rates in different countries here (click the Epidemiology section): http://bit.ly/2p9Ne67
Notice how the countries with more people with HLA-DQ2 or 8 also have more people with celiac disease!
*What tests are involved for diagnosing celiac disease?*
The Celiac Disease Foundation has great explanations:
Blood test and Genetic Screening: http://bit.ly/2hqRIjN
*What about wheat allergies and other gluten-induced diseases?*
Celiac disease is a slow, autoimmune disorder that damages the intestines. Wheat allergies occur very quickly and can result in anaphylactic shock, but damage to tissue is limited. Imagine a peanut allergy, but with gluten instead. Gluten ataxia is when the autoimmune damage is to the brain instead of the intestine, resulting in loss of motor coordination. Finally, non-celiac gluten sensitivity is a blanket term that is diagnosed by elimination – if a person’s symptoms get better after going on a gluten-free diet but tests have been negative for the previous three conditions, then they are diagnosed with NCGS. Symptoms include both intestinal and non-intestinal (headaches, depression, fatigue) symptoms, but the mechanism is unknown.
*Why do some celiac disease patients develop rashes?*
Medically, this rash is called dermatitis herpetiformis, and is described as an intensely itchy blistering that can occur anywhere on the body. While the mechanisms are not well understood, scientists believe that the tissue transglutaminase antibodies that are produced in the intestine eventually enter the bloodstream and end up binding to tissue transglutaminase found in the skin (epithelium). Antibodies stimulate the immune system, resulting in inflammation that causes itchiness and a burning sensation, which subsides after going on a gluten-free diet.
*What is refractory celiac disease?*
Refractory celiac disease describes the condition in which even after going on a gluten-free diet for over a year, the intestine does not recover and symptoms persist. It is not well understood what causes this phenomenon. If this is the case, immunosuppressants such as steroids should be used to suppress the immune system. However, most causes of “refractory” celiac disease are actually due to the patient still eating gluten without realizing it. This is why it is so important for people to know what contains gluten and what does not.