The gluten-free diet seems to be the latest fad when it comes to dieting and healthy living – invite a group of friends to dinner and you can be sure that at least one of them will hold off one of your dishes because it’s not ‘free from’ something. Most often, that something is gluten. The thing is, few people truly suffer from some type of gluten intolerance, and fewer still suffer from Celiac.
An interesting study published in Allergy, The European Journal of Allergy and Clinical Immunology, showed a considerable tendency for parents to diagnose allergies in their children which, when subject to appropriate allergy tests, turn out to be negative. Could we be doing the same with gluten intolerance and celiac disease?
Celiac Disease vs Gluten intolerance
How many of your friends have decided they are celiac and can only eat gluten-free food? What people sometimes don’t understand is that there is a difference between celiac disease (CD) and gluten intolerance.
Celiac disease is an autoimmune disorder where the ingestion of gluten leads to damage in the small intestine, causing a range of potential complications from nutrient malabsorption to long-term health issues. Gluten intolerance, or non-celiac gluten sensitivity, manifests with symptoms similar to celiac disease but without the autoimmune response and intestinal damage, making it less severe but still bothersome.
| Aspect | Celiac Disease | Gluten Intolerance |
|---|---|---|
| Nature | Autoimmune disorder | Sensitivity without autoimmune response |
| Response to Gluten | Damages the small intestine | Causes symptoms but no intestinal damage |
| Diagnosis | Blood tests, biopsy of small intestine | Based on symptoms; no specific tests |
| Long-term effects | Can lead to anemia, osteoporosis, among others | Typically no long-term health complications |
| Treatment | Strict lifelong gluten-free diet | Gluten-free diet to alleviate symptoms; not as strict |
Patients might also not be aware that avoiding gluten might come at a cost: a gluten-free diet could actually be depriving them of some important minerals and nutrients. Worse still, a gluten-free diet could also lead to weight gain – surprising but true!
Often, gluten-free products might have other ingredients in them that add to the overall fat, calorie or salt content. These other ingredients are added in order to enhance their flavors and make them as palatable and tasty as their gluten-containing counterparts – for example, potato starch is often used in gluten-free products to replace flour but is actually higher in calories.
Another interesting study found that approximately one-third of non-celiac gluten sensitivity (NCGS) patients continue having symptoms even after giving up gluten completely. It’s not exactly clear why this happens — it may be due to diagnostic error, poor dietary compliance, or other reasons — but it does show that we don’t really get gluten, or at least not as well as we think we do.
Celiac (sometimes spelled coeliac) is an autoimmune disease, affecting around 1% of the population. It is more common than lupus or rheumatoid arthritis, which fall into the same category. The disease affects our digestive system as well as other organs and parts of our body. It’s triggered by eating gluten, a mixture of proteins found in wheat, barley, rye, and derivatives, with research indicating that there are also environmental factors associated with the condition.
Still, family and twin studies have shown that celiac disease is largely hereditary. Family members sharing the same genotype with a direct, blood family member with celiac disease have a 40% chance of also developing the disease.
Whilst celiac disease is an autoimmune disease, it has far wider-reaching side effects and consequences. It is a condition that can be pretty hard to diagnose – if you truly suffer from celiac disease, a genetic test could give you the answer you need.
The problem with gluten
Gluten is simply a protein found in flour and its many products and derivatives. Imagine the elastic texture in a dough — that’s gluten at work. It’s what gives bread its chewiness and pasta its firmness.
Some people can be either intolerant to gluten, sometimes referred to as non-celiac gluten intolerance (NCGI) or gluten sensitivity, or actually be celiac (and suffer from celiac disease). There’s a big difference between the two, and being celiac is far more serious than being gluten intolerant. You can be gluten intolerant but not have celiac disease, and that’s what happens in most cases.
Celiac disease can have very serious consequences – the person’s immune system attacks its own intestine resulting in damage to the intestinal villi – small, finger-like structures which are important for the absorption of nutrients like water soluble vitamins. This damage is medically known as villous atrophy and can result in malabsorption or non-absorption of important nutrients which can lead to malnourishment.
Now, on the other hand, gluten intolerance or sensitivity is a different kettle of fish. Some physicians do not even believe gluten intolerance exists and others note that it differs from celiac disease because it does not trigger an autoimmune reaction and thus has nothing to do with it.
Is there a cure for Celiac?
If you suffer from Celiac, there’s not a cure per se. The only viable way to treat celiac disease is to eliminate all gluten from your diet. If you are gluten intolerant (not celiac), then you will get by consuming gluten from time to time without too much discomfort (depending on just how intolerant you are).
In 2018, scientists tested a vaccine for Celiac patients that could allow them to consume gluten. However, a year later the clinical trials were discontinued after results proved underwhelming.
Overall, you will still need to avoid gluten-containing products if you are intolerant but you can “sin” from time to time.
Genetic testing for celiac disease?
So, if eating bread and pasta makes you feel bad, how do you know what you’re suffering from? Basically, the simplest and often best thing you can do is carry out a genetic predisposition test to confirm whether you carry certain genes that are known to be implicated in celiac disease.
But besides genetic testing, there is also a blood antibody screening test which is widely used. The antibody test and the genetic test are, however, different. A blood test (serology test) looks at the levels of Tissue Transglutaminase Antibodies (tTG-IgA) antibodies in the blood. The antibodies are triggered in response to gluten ingestion. Positive results would suggest that the patient suffers from celiac disease.
However, the blood test requires that the individual follows a gluten-containing diet – something that can cause a lot of discomfort for the celiac disease patient. For individuals on a gluten-free diet, doctors might suggest a “gluten challenge” whereby small amounts of gluten are reintroduced in order for levels of antibodies to gradually increase in the blood. If levels of antibodies are too low, the test may give false negative results.
The celiac disease genetic test requires that you collect a DNA sample using mouth swabs and it is a very different test to the antibody test outlined earlier. To understand the disease on a genetic level we need to look at celiac DQ genetics – specifically the HLA DQ2 and DQ8 gene. The genes responsible for celiac disease are those found on chromosome 6 where we find what is known as the Human Leukocyte antigen.
The genetic variations HLA-DQ2 and HLA-DQ8 are the main genes responsible for celiac disease although there are some others that may be involved. HLA-DQ2 gene accounts for around 95% of Celiac disease patients, whilst 5% have HLA-DQ8. The test may show the individual tested is at a high risk of being Celiac or developing Celiac at any time in their life. This does not mean that at the moment of testing, the individual is a Celiac sufferer.
The genetic test relies on a technique used in molecular biology known as Polymerase chain reaction (PCR) which enables the amplification of extracted DNA.
A Celiac genetic test does not require that the individual follows a gluten-free diet as the test looks at a person’s genes. Once the genetic DNA test indicates you could have Celiac, you may need to eliminate gluten from your diet. Negative results for both HLA-DQ2 and HLA-DQ8, mean that you have a 99% chance of not developing the disease.
Is there an ideal Celiac test?
It is important to note that HLA genetic testing is not a perfect test to confirm whether you are celiac or not. A doctor would likely suggest a combination of tests and advise on one test based on the results of a previous examination.
A genetic HLA screening test will only show whether you have a high or low predisposition to the disease – you may or may not, at the time of testing, have developed celiac disease. It is however very useful as a test to exclude celiac disease if a doctor suspects you might have it. On the other hand, a blood (serologic) antibody test is a good screening test to start off. Neither of these tests is diagnostic.
The only procedure that is diagnostic is an endoscopic biopsy – this will determine, through analysis of an actual intestinal tissue sample, the extent of the damage caused by the disease and whether the damage observed is consistent with celiac disease.
Hidden gluten
There’s nothing inherently wrong in having a gluten-free diet, as long as you are aware of two things: first, you can’t self-diagnose yourself with celiac or gluten intolerance, you need a test for that, and second, you have to pay extra attention to gluten-free products.
We know that cookies, cakes, pasta, bread crackers, and many more baked delights contain gluten. But gluten is a hidden ingredient in many foods and medicines. Watch out for things such as soy sauce – it often contains gluten as it is made with wheat (besides salt, soy, and other ingredients). This means that even sushi in a restaurant might be a problem. You might want to consider taking your own little jar of gluten-free soy sauce.
Those readymade soups: so tasty, quick and convenient, and often also so high in gluten. Ice cream is another well-loved treat that could contain gluten. This is all the more obvious if you are eating a biscuit chip ice cream as the chips themselves will contain gluten. Other gluten-rich foods include sausages, preserves, cubes, toothpaste, and dietary supplements.
Oats are funny in this regard. There is a common misconception that oats contain gluten. Well, this is not true… or rather, not really true. Oats are not naturally gluten-containing cereals in their natural state. But they do get processed in facilities that would naturally process other cereals and products that would contain gluten. This means that the oats will get contaminated with gluten from the machinery used in the processing plants.
Bibliography
Genetic Testing Laboratories. (2017). Celiac Disease Genetic Testing. [online] Available at: https://www.gtldna.co.uk/celiac-disease-genetic-testing/ [Accessed 28 Feb. 2017].
Klein, S. (2014) Things You Should Know Before Going Gluten-Free – Celiac Disease Foundation. [online] Celiac Disease Foundation. Available at: https://celiac.org/blog/2014/02/9-things-you-should-know-before-going-gluten-free/ [Accessed 20 Feb. 2017].
Venter, C. et al (2008) Prevalence and cumulative incidence of food hypersensitivity in the first 3 years of life. [online] Available at: http://onlinelibrary.wiley.com/doi/10.1111/j.1398-9995.2007.01570.x/pdf [Accessed 20 Feb. 2017].
Geddes, L. (2015). Leave it out: are food intolerances fact or fad?[online] The Guardian. Available at: https://www.theguardian.com/society/2015/aug/16/leave-it-out-are-food-intolerances-fact-or-fad-gluten-dairy-free-from-coeliac [Accessed 20 Feb. 2017].
Leger, A. (2015) Genetic Testing Can Reveal Your Family’s Chances of Developing Celiac Disease [online] Gluten-Free Living. Available at: https://www.glutenfreeliving.com/gluten-free/celiac-disease/genetic-testing-celiac-disease/ [Accessed 20 Feb. 2017].
Gluten. (2017). [online] En.wikipedia.org. Available at: https://en.wikipedia.org/wiki/Gluten [Accessed 20 Feb. 2017].
Anderson, J. (2016). Gluten Sensitivity vs. Celiac Disease: What’s the Difference? [online] Verywell. Available at: https://www.verywell.com/gluten-sensitivity-vs-celiac-disease-562964 [Accessed 20 Feb. 2017].
Majd, S. (2017). What Is Celiac Disease?. [online] Scientific American. Available at: https://www.scientificamerican.com/article/what-is-celiac-disease/ [Accessed 20 Feb. 2017].
Storrs, C. (2011) Will a gluten-free diet improve your health? [online] Edition.cnn.com. Available at: http://edition.cnn.com/2011/HEALTH/04/12/gluten.free.diet.improve/index.html [Accessed 20 Feb. 2017].
