The Science of Celiac
The number of cases of celiac disease is on the rise. Is celiac disease the new black, or is something else going on? Ask Science explains.
The number of cases of celiac disease, (or coeliac, as it is spelled in the UK), is on the rise. The current estimates are that 1 out of every 100 people have celiac disease. So what’s the cause of this increase in cases? Is it part of an anti-gluten conspiracy? Is celiac just the cool new thing in disease diagnosis? Let’s learn more.
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As I mentioned in a previous episode, wheat contains a protein-complex called gluten. Gluten proteins stick to one another and to other things in flour to form what is called the “gluten matrix.” This property is where gluten gets its name, from the latin word for “sticky.” When yeast is added to dough, it generates carbon dioxide which tries to escape from the dough, and pushes against this gluten matrix on its way out, causing the dough to rise.
When you eat this gluteny goo and it reaches your intestines, an enzyme in your body called tissue transglutaminase (tTG) breaks the gluten up for digestion by binding itself to the gluten and breaking bits off.
Normally this is no big deal, but sometimes your immune system sees these bits of gluten with tTG stuck to them and goes into overzealous security guard mode, thinking: “Hey that looks suspicious. Attack!” So a bunch of antibodies get created which stick to the tTG/gluten bits so that they can be destroyed by your immune system. Unfortunately your intestines suffer collateral damage in this attack, which leads to all sorts of issues.
Signs of Celiac
Celiac disease used to be relatively hard to diagnose because it doesn’t have a distinct set of symptoms. The most common symptoms are chronic diarrhea or constipation. Sometimes there is abdominal pain, cramping, bloating, and fatigue.
Sometimes however the disease can go unnoticed because people don’t get these symptoms, or don’t notice them. Since celiac disease damages your intestinal tract, it can lead to malabsorption of other nutrients, which can lead people to think they have other illnesses. For example, anemia is a common side effect of celiac disease, because iron is no longer being absorbed properly. Osteoporosis is a potential complication because your body stops absorbing calcium and vitamin D correctly.
One of the other problems is that sometimes the damage caused by celiac disease doesn’t manifest itself until later in life. Scientists are now realising that many children that were historically diagnosed with growth failure, failure to thrive, and infantilism where likely suffering celiac disease. Sometimes you might not have any of the other symptoms but have really low vitamin D levels because of your intestines not absorbing things correctly. Frequent miscarriages, infertility, lactose intolerance, and other autoimmune conditions such as vitiligo and occasionally hypothyroidism can also be a result of the damage caused by celiac disease.
Diagnosing Celiac
Up until recently, diagnosing celiac disease was difficult because of its wacky symptoms. However, in the last couple of years, several blood tests have been developed that do a very good job of diagnosing celiac disease. Scientists have given these handy names to help you easily remember them:
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tTG-IgA – This is a blood test that measures how many tTG antibodies you have in your blood. You shouldn’t have very many because your body shouldn’t be attacking itself. If this number is really high, there is a 90-95% chance you have celiac disease.
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EMA – Another blood test that screens for antibodies, but is less sensitive than the tTG-IgA and is no longer recommended.
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DGP – A new test that is supposed to be even better than the tTG-IgA, especially in children, but isn’t widely used yet.
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HLA – A genetic test done by submitting a swab of cheek cells. There are certain gene variations that make you more likely to have celiac disease.
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igG-giladin – A test that can be useful to see if you have an adverse reaction to gluten that is not celiac disease (more on that later).
In the UK, the current standard is to use test number 1 to see if you have high levels of antibodies. If you do, you’re referred to a gastroenterologist who does a endoscopic biopsy where pictures and samples of your intestines are taken for analysis. This analysis serves two purposes. First it confirms with full certainty if you have celiac or not (rather than only being 90-95% certain). Second, it provides a measurement for how damaged your intestines currently are.
Other Gluteny Things
Some people have problems with gluten, but don’t have celiac disease. Problems with gluten can be broken up into two categories: allergic reactions and immune system reactions.
People with allergic reactions to gluten may have anaphylactic shock or other typical allergic reaction symptoms, or they may get contact urticaria, which is a bunch of red, welt-like patches on the skin. Some people also have respiratory allergies to gluten.
Many things previously written off as IBS, IBD, malabsorption, anemia, or “failure to thrive” are now known to really be caused by celiac disease.
Immune system reactions to gluten can include things such as celiac disease or gluten ataxia (which is an autoimmune condition triggered by gluten where your immune system attacks part of your brain which can cause balance issues, and has been associated with – but not known to cause – depression, dementia, loss of sensitivity in your extremities, and seizures). Other immune reactions to gluten can include dermatitis herpetiformis, which is a super bright-red rash that looks like herpes but isn’t herpes.
Gluten-Intolerence Is the New Black
Some researchers believe that the prevalence of celiac disease isn’t increasing. Instead they believe that public awareness and our ability to diagnose celiac disease have just gotten much much better. Many things previously written off as IBS, IBD, malabsorption, anemia, or “failure to thrive” are now known to really be caused by celiac disease.
If you had gone to the doctor 10 years ago with chronic diarrhea and general fatigue, they probably would have said “You have Irritable Bowl Syndrome” or “maybe you’re lactose intolerant.” If you go with the same symptoms today, the first step is a blood test to screen for celiac. It’s really only been in the last 5 – 10 years that we’ve gotten decently good at diagnosing celiac disease.
Another possibility is that over the centuries, strains of wheat have been selectively bred by farmers to produce better flour, which means having more gluten. So over the centuries the amount of gluten in commercial wheat has increased.
See also: Have We Bred the Nutrition Out of Our Food?
Another hypothesis is that modern society lives in such a sterile environment with antibacterial everything, that our immune system is just hypersensitive. A few researchers believe that introducing children to gluten at too young of an age can lead to an increased risk of celiac disease.
Finally, since celiac disease is a non-lethal genetic variant (meaning that people born with those genes don’t usually die at a young age), those genes have spread through the population.
It could be any, all, or none of these reasons.
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Bread caution image courtesy of Shutterstock.
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About the Author
Dr. Lee Falin earned a B.S. in Computer Science from the University of Illinois, then went on to obtain a Ph.D. in Genetics, Bioinformatics, and Computational Biology from Virginia Tech.
