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Celiac Disease: A Brief Update

wheat fields

Celiac Disease: A Brief Update

Celiac disease, once considered a rare condition, more and more people are been diagnosed with this autoimmune disorder.

 

Celiac disease (CD) is a life-long autoimmune disease that affects about 1.4% of the world population, according to a recent review1. In Australia, it is estimated that about 1.2% adult males and 1.9% of adult females2 suffer from this condition. It is also estimated that as many of 80% of Australians who suffer this condition (about 160,000 people) remain undiagnosed for many years.

Despite being a relatively rare disease, it is surrounded by various myths, such as being a type of allergy, that it is a disease that only affects children or that it is not a serious condition and that it will eventually go away. These are all myths.

People with celiac disease have a life-long autoimmune response to prolamins and glutelins. This is a group of proteins, collectively known as gluten, found in wheat, rye and barley. When these proteins enter the body of someone with CD, immune cells treat them as an invading pathogen and mount an attack. As a result, the intestinal cells responsible for nutrient absorption are damaged.

What causes Celiac disease?

 

At its core, CD is a genetic condition: people with this disease have a genetic predisposition which causes their immune system to attack gluten proteins. For instance, almost all people who develop CD carry the gene variants (called haplotypes) HLA-DQ2 and/or HLA- DQ8.

However, not all people who carry these haplotypes develop CD, which means that there are other factors involved3. This means that there may be other genes or environmental factors involved.

Genome-wide studies, for instance, have identified nearly 40 genomic regions that seem associated with an increased risk of developing CD. Non-genetic factors that have also been proposed include breastfeeding, infant eating habits, mode of birth (C-section vs natural), the gut microbiome and smoking3-4.

Whether other factors are involved in the development of CD is still a subject of further scrutiny. The role of gluten, however, is clear: when someone with CD eats food containing gluten, their immune system reacts, causing havoc.

Diagnosing Celiac disease

 

Several symptoms are associated with CD, including malfunction of the small intestine, as well as gastrointestinal and extra-intestinal symptoms (Figure 1). For example, some people with CD develop dermatitis herpetiformis, an itchy skin rash with bumps and blisters, or gluten ataxia, a disorder that can manifest itself in different ways, such as having trouble speaking, moving the eyes or extremities, and other neurological problems5-6. Someone with CD could also experience iron deficiency, bloating, constipation, chronic fatigue, headache, abdominal pain, and osteoporosis3.

However, there is no unique set of symptoms that affects everyone with CD. For instance, while some people with CD can experience loose stools, abdominal discomfort or flatulence, others experience no symptoms at all. Furthermore, many of the symptoms associated with CD can also occur because of other conditions, like irritable bowel syndrome. This may explain why so many people with CD remain undiagnosed for many years.

In order to get an accurate CD diagnosis, you need to get a positive result from a celiac-specific blood test and go through a small intestinal biopsy. This would show abnormalities in the intestinal villi, finger-like projections found in the upper layer of the intestine involved in nutrient absorption. Only after positive results from these two tests can you be certain of having CD.

The nascent CD – Microbiome connection

 

In the past 15 years, studies have identified significant correlations between the development of CD and the gut microbiome. People with CD, for example, have been found to host elevated numbers of species from ClostridiumPrevotella and Actinomyces bacteria7. Other studies have found evidence of gut dysbiosis in people with CD8-9. Even some viruses, such as rotavirus and reovirus have been linked to the development of this condition10-12.

However, there is no consensus yet on what roles microorganisms are playing in CD, whether positive or negative. For instance, one study has suggested a positive effect of microbes on CD. In this study, researchers found that Herpes viruses and the bacterium Helicobacter pylori may act as protective agents against the development of CD13. Another study, which employed children with CD, found that the use of probiotics containing the gut bacteria Lactobacillus plantarum and L. paracasei influenced the levels of specific immune cells14.

However, there is not enough data to make any firm claims on the potential roles gut microbes may have on CD. Also, we still don’t know exactly how such microbial influence on CD would work. So far, some potential mechanisms have been proposed13, but none has been confirmed15-16.

Prevention, Treatment and cure

 

Currently, there is no verified approach to prevent the development of this condition. While a promising 2013 study found evidence that early exposure to gluten led to a lower risk of developing the disease17, further studies failed to support this association18-21. Hence, based on studies so far, early diet does not seem to be a way to avoid the development of this condition in children.

There is also no known cure for CD.  Because of the genetic basis of CD, there is no intervention that can change the behaviour of the immune system towards gluten, which is primed, whether by genetic or environmental factors, to attack gluten proteins.

On the positive side, appropriate treatment of CD can lead to a normal life that is free from most of the common symptoms.

At the Australian Centre for Functional Medicine, we perform comprehensive testing of your condition to ensure we can do an accurate diagnosis and develop an effective treatment plan.

References

 

  1. Singh P, Arora A, Strand TA, Leffler DA, Catassi C, Green PH, Kelly CP, Ahuja V, Makharia GK. Global prevalence of celiac disease: systematic review and meta-analysis. Clinical Gastroenterology and Hepatology. 2018 Jun 1;16(6):823-36. Read it!
  2. Walker MM, Ludvigsson JF, Sanders DS. Coeliac disease: review of diagnosis and management. Medical Journal of Australia. 2017 Aug;207(4):173-8. Read it!
  3. Lebwohl B, Sanders DS, Green PH. Coeliac disease. The Lancet. 2018 Jan 6;391(10115):70-81. Read it!
  4. Wijarnpreecha K, Lou S, Panjawatanan P, Cheungpasitporn W, Pungpapong S, Lukens FJ, Ungprasert P. Cigarette smoking and risk of celiac disease: A systematic review and meta-analysis. United European gastroenterology journal. 2018 Nov;6(9):1285-93. Read it!
  5. Ortiz BD, Macchi H, Rebull CV, Dominguez ML, Barboza G. Dermatitis herpetiformis: celiac disease of the skin. Report of two cases. Our Dermatology Online. 2018;9(1):44. Read it!
  6. Bi D, Coon E. Extraintestinal Manifestation of Celiac Disease: Gluten Ataxia: 2570. American Journal of Gastroenterology. 2018 Oct 1;113:S1429-30. Read it!
  7. Ou G, Hedberg M, Hörstedt P, Baranov V, Forsberg G, Drobni M, Sandström O, Wai SN, Johansson I, Hammarström ML, Hernell O. Proximal small intestinal microbiota and identification of rod-shaped bacteria associated with childhood celiac disease. The American journal of gastroenterology. 2009 Dec;104(12):3058. Read it!
  8. Wacklin P, Laurikka P, Lindfors K, Collin P, Salmi T, Lähdeaho ML, Saavalainen P, Mäki M, Mättö J, Kurppa K, Kaukinen K. Altered duodenal microbiota composition in celiac disease patients suffering from persistent symptoms on a long-term gluten-free diet. The American journal of gastroenterology. 2014 Dec;109(12):1933. Read it!
  9. Sánchez E, Donat E, Ribes-Koninckx C, Fernández-Murga ML, Sanz Y. Duodenal-mucosal bacteria associated with celiac disease in children. Appl. Environ. Microbiol.. 2013 Sep 15;79(18):5472-9. Read it!
  10. Verdu EF, Caminero A. How infection can incite sensitivity to food. Science. 2017 Apr 7;356(6333):29-30. Read it!
  11. Kemppainen KM, Lynch KF, Liu E, Lönnrot M, Simell V, Briese T, Koletzko S, Hagopian W, Rewers M, She JX, Simell O. Factors that increase risk of celiac disease autoimmunity after a gastrointestinal infection in early life. Clinical Gastroenterology and Hepatology. 2017 May 1;15(5):694-702. Read it!
  12. Bouziat R, Hinterleitner R, Brown JJ, Stencel-Baerenwald JE, Ikizler M, Mayassi T, Meisel M, Kim SM, Discepolo V, Pruijssers AJ, Ernest JD. Reovirus infection triggers inflammatory responses to dietary antigens and development of celiac disease. Science. 2017 Apr 7;356(6333):44-50. Read it!
  13. Lerner A, Arleevskaya M, Schmiedl A, Matthias T. Microbes and viruses are bugging the gut in celiac disease. Are they friends or foes?. Frontiers in microbiology. 2017 Aug 2;8:1392. Read it!
  14. Håkansson Å, Andrén Aronsson C, Brundin C, Oscarsson E, Molin G, Agardh D. Effects of Lactobacillus plantarum and Lactobacillus paracasei on the Peripheral Immune Response in Children with Celiac Disease Autoimmunity: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial. Nutrients. 2019 Aug;11(8):1925. Read it!