Tag Archives: celiac

Chemical exposure, not just genetics, could induce gluten intolerance

The risk of developing celiac disease (the most extreme form of gluten intolerance) in young people seems to be associated with elevated blood levels of toxic chemicals found in pesticides, nonstick cookware, and fire retardants.

A new study from the NYU Grossman School of Medicine suggests that children and young adults with high blood levels of dichlorodiphenyldichlorethylenes (DDEs), a class of chemicals associated with pesticides, were twice as likely to be diagnosed with celiac disease compared to their peers. Celiac disease is an immune disorder that creates severe reactions in the gut to foods containing gluten.

Gender matters, too

“Our study establishes the first measureable tie-in between environmental exposure to toxic chemicals and celiac disease,” says senior study author and pediatric gastroenterologist Jeremiah Levine, MD.

“These results also raise the question of whether there are potential links between these chemicals and other autoimmune bowel diseases, which all warrant close monitoring and further study,” says Levine, a professor in the Department of Pediatrics at NYU Langone.

The team analyzed chemical levels in the blood of 30 children and young adults (aged 3 to 21), who were newly diagnosed with celiac disease at NYU Langone Hassenfeld Children’s Hospital. The results were compared to a similar analysis of 60 young people of similar age, gender, and race.

The authors report that men and women react differently to such exposure to toxins. Women make up the majority of celiac cases, they note, and the team found that they were eight times more likely to develop gluten intolerance following higher-than-normal exposure to pesticides.

Furthermore, young women with elevated blood levels of non-stick chemicals known as perflouoroalkyls (PFAs) — including Teflon — were five to nine times more likely to have celiac disease.

Young men with high blood levels of of fire-retardant chemicals polybrominated diphenyl ethers (PBDEs) were twice more likely to be diagnosed with celiac disease.

The study didn’t establish a clear cause and effect relationship between these chemicals and celiac disease, but the authors note that they are all known to disrupt animal and human hormone levels, which are key to controlling both sexual development and immune defenses against infection. The authors call for more in-depth research on the topic.

Our understanding up to now is that celiac disease, which affects around 1% of the world’s population, is largely genetically-driven. However, if other studies support the results of this study, it could radically alter our understanding of this condition, alongside other autoimmune disorders.

The paper “Persistent organic pollutant exposure and celiac disease: A pilot study” has been published in the journal Environmental Research.

Baked cake.

What is gluten intolerance, and what are its symptoms?

Gluten is a protein naturally found in cereals such as wheat, barley, and rye. Harmless for most of us, gluten can cause quite a lot of headache (and bellyaches, among other things) for certain people. Today, we’ll take a look at the different kinds of gluten intolerance and the symptoms they can cause.

Baked cake.

Gluten makes dough elastic, knead-able, and bouncy. You can see how it works in this cake, keeping those stringy bits in the middle from breaking.
Image credits Andreas Lischka.

Wheat (genus Triticum) makes the world go round. Not literally, but it does play a big role in keeping us humans fueled up. It was one of the first domesticated food crops, and for roughly 8 millennia now, wheat has been the staple food of major civilizations in Europe, North Africa, and West Asia. More land area is dedicated to growing wheat than any other commercial crop on Earth, and global production of wheat outstrips that of any other crop — including rice, maize, and potatoes.

Barley (Hordeum vulgare) is another long-time companion of human farmers. First cultivated around 10,000 years ago, it was the fourth most-produced grain in the world in 2016, although output has somewhat declined since then. Barley is very useful as an animal feed but is perhaps most celebrated for its role in beer and distilled beverage production.

Both of these cereals, along with rye, their related species, and various hybrids, are part of the grass (Poacea) family of plants. Altogether, they supply a huge part of the calories and nutrients consumed by us and our livestock. They also supply the majority of raw materials used in producing alcohol.

Apart from their economic importance, these crops are also notable for their high content of gluten and gluten-like proteins. This is a bit of a bummer for around 1.5% to 14% of the world’s population, who have to contend with various forms of gluten intolerance.

What is gluten intolerance

Gluten intolerance is a somewhat-umbrella term that refers to adverse reactions to gluten. I say ‘somewhat-umbrella’ because it tends to be improperly applied to several conditions that — while similar in effects — are different in origin. These include celiac disease (CD), non-celiac gluten sensitivity (NCGS), wheat allergy, dermatitis herpetiformis, and (more rarely) gluten ataxia.

The most extreme form of gluten intolerance is celiac disease (also known as gluten-sensitive enteropathy, sprue, or coeliac). Roughly 1 in 100 Americans contend with CD, and this percentage seems to hold true for the rest of the world as well. CD is basically an autoimmune disorder. The body of a CD patient reacts with extreme violence to the presence of gluten in one’s food — to the point where their immune system will attack the inner lining of the small intestine to ‘protect it’ from gluten. Such offensives cause immediate symptoms for the patient. If exposure to gluten is maintained over a longer period of time, sustained damage to the gut’s lining leads to problems in absorbing nutrients (malabsorption).

Celiac disease gut lining.

High-magnification image of intestinal lining damaged by celiac disease.
Image credits Nephron / Wikimedia.

Non-celiac gluten sensitivity is more controversial. We don’t know, really, what causes this condition (or if it’s even an actual thing). Our best guess is that it has something to do with gluten-associated proteins and/or other chemical compounds present in gluten-containing crops. Since we don’t know what causes it and how, NCGS is generally diagnosed by eliminating other possibilities (namely CD and wheat allergies). Roughly 0.5% to 13% of the world’s population has NCGS. While its exact symptoms are debated, NCGS seems to share most gastrointestinal symptoms of CD, wheat allergies, and irritable bowel syndrome, but with a different interval between exposure and onset of symptoms. NCGS also seems to entail a host of extraintestinal (not related to the gut) symptoms that CD lacks.

Wheat allergy is your run-of-the-mill allergy, but rather misleadingly-named. Like other allergies, it can manifest as a food- or contact-allergy. Unlike other allergies, it can be caused by a range of compounds (rather than a particular allergen) contained in wheat. The European Center for Allergy Research Foundation (ECARF) states that “wheat allergy generally appears in infancy,” noting that roughly 0.3% of European children under the age of 5 and around 0.1% of all Europeans are allergic to wheat, making it a relatively rare condition.

Dermatitis herpetiformis (DH), or Duhring-Brocq disease, is a tell-tale sign of celiac disease, although the exact mechanism by which one causes the other remains unknown. The condition is a skin inflammation characterized by chronic rashes on the skin with red, liquid-filled blisters. They’re also very itchy. Estimates of DH prevalence range from 10 in 100,000 to around 80 in 10,000 individuals.

Gluten ataxia is a proposed condition. It’s basically gluten-induced ataxia, a condition characterized by dysfunctions in the central nervous system leading to loss of voluntary control or coordination over muscle movements. Gluten ataxia “usually presents with gait and lower limb ataxia” and may account for “15% amongst all [cases of] ataxias and 40% of all idiopathic sporadic ataxias,” according to a study published in 2015.

It’s important to note that there are several varieties of gluten intolerance going forward. Each has its own particularities of symptoms. However, there are some general symptoms that are indicative of such disorders.

Symptoms of gluten intolerance

Abdominal pain.

Most of them have to do with your belly. But not all of them.
Image credits Darko Djurin.

Abdominal pain after ingesting gluten — from grains and derived products such as flours, bread, baked goods, or beer — is the most common symptom of gluten intolerance at large. Up to 83% of those with gluten intolerance experience abdominal pain and discomfort after eating gluten.

Abdominal bloating is a close second. It’s a sensation of ‘swollenness’ or ‘fullness’ in one’s belly, caused by the release of gases in the gut. Generally uncomfortable, abdominal bloating can become painful and/or cause shortness of breath. Around 87% of people suspected to have NCGS experience bloating, but a majority of CD patients also report this symptom.

Bowel inflammation after consuming gluten is a common symptom of celiac disease. Damage of the gut lining causes inflammation resulting in significant digestive discomfort. In the long run, it can also lead to poor nutrient absorption.

Over 50% of gluten-sensitive individuals (both CD and NCGS) regularly experience digestive symptoms such as diarrhea, while about 25% experience constipation. Patients also report alternating between the two states. Celiac disease patients may also experience pale and foul-smelling feces (due to nutrients left over in the stool).

Tiredness after consuming gluten can also be a symptom. This is a bit trickier to diagnose, as life by itself tends to be quite tiresome. However, if you regularly (or constantly) feel fatigue and tiredness, especially after eating foods that contain gluten, it could be indicative of underlying gluten intolerance. Around 60% to 82% of gluten-intolerant individuals commonly experience tiredness and fatigue. Gluten intolerance can also cause iron-deficiency anemia, which in turn will make you feel tired and spent overall.

Dermatitis herpetiformis, as we’ve seen above, is a pretty dead giveaway for celiac disease. Other skin conditions — psoriasis, alopecia areata, and chronic urticaria — have also shown improvement under gluten-free diets, which suggests a link between them and gluten intolerance.

Gluten intolerance may also predispose individuals to depression and anxiety, especially those suffering from CD. While the mechanism underlying this link remains unknown, it has been proposed that changes in gut flora and exorphins formed during gluten digestion may interfere with serotonin levels in the brain. It also seems that switching to a gluten-free diet makes some patients “feel better” even if their gastrointestinal symptoms persist; all of which suggests a link between the two.

What to do about it

Brad and grains.

TL;DR don’t put these things in your mouth.
Image credits National Cancer Institute / National Institutes of Health.

The best course of action is to go talk to a doctor. But there are some preventive measures you can take if you think you’re suffering from gluten intolerance.

Unsurprisingly, you should avoid items that contain gluten — wheat, barley, malt, rye, and their derived products (brewer’s yeast can also contain gluten, for example). Some common foods and drinks that contain gluten include:

  • pasta, noodles
  • bread, pastries, baked goods such as crackers, biscuits, and cakes
  • breakfast cereals
  • pancakes, waffles, crepes
  • many sauces and gravies use flour-derived gluten as thickening agents
  • beers, malt beverages
  • potatoes, maize, and rice can also become contaminated with gluten in facilities that also process gluten-rich grains

Gluten-free varieties of such items are commercially available, although they tend to be more pricey. So it’s possible to enjoy them without worrying about gluten. But, as a rule of thumb, if you suspect a food item contains or has been in contact with wheat, barley, rye, malt, or products derived from those (and you believe you might be suffering from gluten intolerance), don’t eat it.

Now, I think it’s important to note that there’s also somewhat of a witch hunt among fad diets regarding gluten. Many such diets suggest gluten itself is bad for your health even if you’re not gluten-intolerant. There’s no credible scientific evidence for such claims that I could find, so I’m comfortable calling it a myth. Another part of the issue is that the symptoms of gluten intolerance are widespread and can have a lot of different potential causes — which makes gluten intolerance easy to misdiagnose.

All in all, if you believe you might be suffering from gluten intolerance, the best course of action is to go talk to a doctor.

On oats

In response to numerous queries concerning the use of oats in various products, the North American Society for the Study of Celiac Disease (NASSCD) released a statement saying that “the use of oats uncontaminated by wheat, barley or rye by individuals with celiac disease and dermatitis herpetiformis in North America has been endorsed by most experts.” However, they also note that “regular (commodity) oats in North America are likely to be contaminated with wheat and barley,” and recommend consulting a doctor or dietitian before including oats in gluten-free diets, as well as monitoring after inclusion.

There is some evidence that avenin, an oat protein similar in form and function to gluten, “can activate gluten-reactive T cells”, the Celiac Disease Foundation reports citing a 2015 study. A different study, published in 2017, reported that avenin “can cause small bowel mucosal damage in some people with coeliac disease.” While the first paper concludes that “low-level oats consumption may be insufficient for clinical relapse in CD patients,” the second one does not recommend including this cereal in gluten-free diets.

It has to be noted, however, that the second study was performed in Australia, and differences in labeling requirements may confuse results to an extent. The NASSCD, for example, specifies that “oats used in labeled gluten-free foods may now include mechanically/optically-sorted oats, a process which separates oats from wheat, barley and rye by color, size, and shape. These methods are used to produce “clean” gluten-free oats.” The first study also suggests that certain types of oats may induce CD symptoms in patients while others do not.

“Inclusion of oats in a gluten-free diet might be valuable due to their nutritional and health benefits, and several countries currently permit oats to be included as an ingredient in such diets,” it explains.

“However, it is extremely important to remember that in vitro studies have shown that the immunogenicity of oats varies depending on the cultivar used. Future clinical studies should be directed to the development of clinical trials with varieties previously identified as safe by reliable in vitro methods”

If you’re intolerant to gluten, play it safe. Look for the “gluten-free” label, or talk to a doctor to decide if oats are right for you.

Gluten-free diets might not be so gluten-free after all

For many people, the gluten-free diet might be little more than a modern fad, but for the approximately 1% of the population who have celiac disease, eating gluten-free foods is imperative if they want to be healthy. A new study suggests that maintaining a gluten-free diet is much more difficult than anticipated. According to the research, patients adhering to a gluten-free diet are frequently exposed to low levels of gluten that contribute to symptoms and persistent intestinal damage.

 

Gluten-free bread. Image via Wikipedia.

Gluten is an umbrella term for the proteins found in wheat. Unfortunately, some people are unable to properly process gluten — a condition by the name of Celiac disease. Celiac disease is a chronic, autoimmune disorder which primarily affects the small intestine after the ingestion of wheat, barley, rye, and derivatives. People may suffer severe symptoms and might suffer greatly after consuming gluten, and naturally, try to avoid that as much as possible.

Most people consume between 5 and 15 grams of gluten per day, on average. For severe Celiac sufferers, even 50 mg a day can cause significant distress — so they try to eliminate gluten completely from their diet. But even keenly aware people may simply be unable to do that. As it turns out, even people who thought they were eating 100% gluten-free had detectable amounts of gluten in their body. So, while some people are more diligent than others and reduce more gluten from their diets, it was almost impossible to completely eliminate gluten from the equation.

The Hidden Gluten

According to a meta-analysis of previously published studies, despite the best efforts of Celiac patients, it’s nigh impossible to escape Celiac. UCI’s Jack Syage and colleagues estimate that typically, Celiac patients consume up to 244 mg of gluten per day. The study estimated the average to be from 150-400 mg using the stool test and 300-400 mg using the urine test. However, it should be recognized that the stool and urine tests are relatively new and the methods continue to be improved, researchers note.

These quantities are sufficient to trigger symptoms, which is already worrying. But where is the gluten coming from? Unfortunately, we don’t know yet. These are just preliminary results which aimed at mapping involuntary gluten consumption. Hopefully, future research will identify the source of this unwanted hidden gluten.

Source: Syage JA et al. Determination of gluten consumption in celiac disease patients on a gluten-free diet. The American Journal of Clinical Nutrition, Volume 107, Issue 2, 1 February 2018, Pages 201–207, https://doi.org/10.1093/ajcn/nqx049

How to tell difference between Celiac disease and Gluten intolerance

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 be sure that at least one of them will hold off one of your dishes because it’s not ‘free from’ something, probably gluten. The thing is, few people do 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, their children did not actually suffer from. Could we be doing the same to ourselves?

Celiac Disease or Gluten intolerance?

How many of your friends have decided they are celiac and can only eat gluten-free food? What people sometimes haven’t understood is that there is a difference between celiac disease (CD) and gluten intolerance. They also are often not 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 which add to the overall fat, calorie or salt content. These other ingredients are added order to enhance their flavors and make them as palatable and tasty as their gluten containing counterpart – 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 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 the eating of gluten, a mixture of proteins found in wheat, barley, rye, and derivatives, with research indicating that there are also environmental factors associated with it. Still, family studies and twin studies have shown that celiac disease is largely hereditary. Family members sharing the same genotype as 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, giving wheat products that typical and characteristic elasticity and chewiness.

Some people can be either intolerant to gluten, sometimes referred to as non-celiac gluten intolerance (NCGI) or gluten sensitivity, or actually suffer celiac (and suffer from celiac disease). There’s a big difference between the to, 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, let us say, 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.

No-gluten Bread. Image via Max Pixel.

What is the Cure?

If you do suffer from Celiac, there’s not a cure per se. The only way to cure celiac disease is to eliminate all gluten from your diet, medicines etc. If you are gluten intolerant (not celiac), then you will get by with consuming gluten from time to time without too much discomfort (depending on just how intolerant you are). But don’t worry, this generally eliminates your symptoms entirely, and in most cases, even if you (rarely) eat gluten, you’ll still be fine. 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 individual tested suffers from celiac disease. However, the test requires that the individual follows a gluten-containing diet – something which can cause a lot of discomfort for the celiac disease sufferer. 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 just discussed. To understand the disease on a genetic level we need to look at celiac DQ genetics – specifically the HLA DQ2 and DQ8. The genes responsible for celiac disease are those found on chromosome 6 where we have 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. 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 be a celiac sufferer and may need to eliminate gluten.  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 the ideal test to confirm whether you are celiac or not. Still, there is no ideal test — it’s not like one is strictly better than the other. A doctor would likely suggest a combination of tests and advise on one test based on the results of a previous. 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 which 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

Beer usually contains gluten, but not every type does. Here are a few gluten-free beers. Image credits: Fredo 93 / Wiki Commons.

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. If you do get diagnose, what should you avoid? Well, the doctor will definitely give you a comprehensive list of what you can and can’t eat, but here’s a short list.

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 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. Obviously, this is all the more obviously if you are eating a biscuit chip ice cream as the chips themselves will contain gluten. Other 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].