What Is Gluten Sensitivity? (part 1)

Bread for Ducks is Death for Ducks

Gluten is a big buzzword right now. More and more people are avoiding gluten, the gluten-free food industry is booming, and there are more gluten-free options than ever at restaurants, bakeries, and grocery stores.

Public opinion has often come down against this movement, claiming that the majority of people going gluten-free are misguided and foolish. A couple of months ago there was a flurry of headlines claiming that non-celiac gluten sensitivity is “Just In Your Head“,  “Completely Fake”, “BOGUS”, and even “Bullshit”.  These stories are sensational and clickable, and quickly made the rounds on social media. Yet, they are examples of frankly terrible news reporting. They misrepresent the study being reported, while displaying both a lack of knowledge of the facts and a lack of consideration for people dealing with health problems.

The truth is, non-celiac gluten sensitivity has not been disproven, and to claim that it has been is simply wrong.

Those particular headlines were in response to one recent study that did not find a link between gluten and digestive symptoms in irritable bowel syndrome (IBS) patients. This was one study, that only examined one specific question about symptoms in IBS patients– thus it did not disprove the fact that a variety of diseases and harmful effects are still linked to gluten, as seen in a huge body of peer-reviwed scientific research and clinical results. In fact, only a couple of weeks after the study was published, the very same research lab published another study that found a connection between gluten and depression. As the head of the research group Peter Gibson said:

“we know that a lot of people go on gluten-free diets, [and] feel better. And that’s not imagination, that’s real.”


“The story is ongoing. We produced a piece of evidence to say that gluten is being overly blamed, but we have patients who we still believe have non-celiac gluten sensitivity.”

This does not sound like someone “saying he got it wrong” about the existence of gluten sensitivty, as the media claimed. Rather, he is saying that this study is one piece in the puzzle of the various effects of gluten, and that there are still many more pieces to look at.

Let us set this study aside for the moment and take a look at one glaring issue: even if this study’s implications are correct and the role of gluten in IBS has been overstated, gluten sensitivity is not just associated with IBS, and it is not even simply a gastrointestinal issue. In fact, one of the main ways that gluten affects the body is through the brain and nervous system, and gluten sensitivity is often exclusively neurological, with no digestive symptoms. Neurological disorders such as migraines, ataxia, dystonia, and peripheral neuropathy are all linked to gluten sensitivity. Psychiatric disorders such as depression, anxiety, schizophrenia, autism, and ADHD  are also tied to gluten sensitivity. Gluten has been strongly linked with autoimmune diseases, which I will talk more about in my next post. It has also been tied to other disorders such as fibromyalgia. This is not to say that gluten is necessarily the sole cause of all of these, but it is at least found to be a contributing factor.

Here are a few examples of recent research into gluten sensitivity:

  • Fibromyalgia is an elusive syndrome that is often associated with gut problems. In a recent study, 20 patients with fibromyalgia experienced remission from the disease on a gluten-free diet. They were all confirmed not to have celiac, thus the researchers concluded that non-celiac gluten sensitivity may be a cause of the disorder.
  • Depression has been shown to be much more common in those with celiac, and conversely, people who are depressed are more likely to have undiagnosed celiac. As I mentioned above, a recent study found that gluten caused depression even in people without celiac. There is also a recently published case study of a girl who had been on a gluten-free diet and suddenly became severely depressed after beginning to eat wheat daily. She did not have celiac disease. After going back to a gluten-free diet, her depression resolved.
  • Scientists have been exploring the links between wheat, gluten, and schizophrenia for decades, and many studies have shown that a gluten-free diet is effective for many patients. One recent fascinating discovery is that even after controlling for other variables, mothers who have a greater than normal immune reaction to gluten have greatly increased odds of having children who develop schizophrenia. The same did not hold true for an immune reaction to milk casein.
  • ADHD (attention deficit hyperactivity disorder) is tied with gluten sensitivity in multiple studies. It has been found that those with ADHD are much more likely to have celiac disease, and when the celiac disease is treated by a gluten-free diet, ADHD symptoms also improve.
  • Autism spectrum is a complex condition with many factors, but many children with autism are greatly helped by a gluten free diet. For example in one study that questioned 387 families with autistic children who were on a gluten-free and casein-free diet, those that reported the closest adherence to the diet also experienced the best improvement in symptoms. From a more biochemical angle, another study found that gluten causes a greater immune reaction in children with autism than in children without autism. Research is ongoing, and shows that gluten-free dietary interventions are promising for improving both symptoms and development in many patients.
  • Type 1 diabetes has been  linked to gluten in multiple studies. One recent study found that for diabetic mice, the risk that their offspring would develop type-1 diabetes was dramatically less when they ate a gluten-free diet during pregnancy and nursing. It has also been shown that if started early enough, a gluten-free diet can cause remission of the disease in humans: one recent case study described a young boy who was diagnosed with type-1 diabetes but was able to put the disease into remission with a gluten-free diet.

You may be wondering: how could gluten be a factor in all of these seemingly unrelated diseases? It is because gluten affects two very integral and vital parts of our bodies: our guts and our immune systems.

Gluten is difficult for our bodies to digest, and is very good at damaging the gastrointestinal tract, aka the gut. Our guts are lined with cells that carefully regulate what substances get through into the rest of the body. Normally only fully digested nutrients should get through, but gluten is able to loosen the spaces between the gut cells and also break straight through them. This is known as “leaky gut”. (AKA “increased intestinal permeability”.)  Leaky gut allows fragments of gluten and larger pieces of food enter the body, where they are recognized as dangerous invaders and set off an immune system attack (inflammation).  Gluten has such a profound effect on the gut that it has been shown to increase leaky gut in all people, even in those without gluten sensitivity. Gluten can also affect the microbes in the gut. Because it is poorly digested by our own bodies, it provides food for microbes, potentially leading to an overgrowth or imbalance in our microbiomes.

These are a couple of the major ways that gluten is known to cause damage and excessive inflammation in the body. It is becoming more and more clear how important the microbiome and the gut are to our health, and chronic inflammation is more and more understood to be at the root of most disease. Our immune systems are designed to respond to a threat with an inflammatory response, and then die down. But if our systems are constantly in attack mode, that can take a toll on our bodies and potentially lead to mistakes, such as attacks on our own cells.

The gut is in many ways the center of health. It is home to most of the symbiotic microbes that are so integral to us, it is (paradoxically) the origin of most of our neurological chemicals, and it is also home to most of our immune system. The gut is where we absorb the food we eat to sustain ourselves, and the gut determines what substances are allowed into the rest of our bodies. Thus, although it may seem implausible that gluten is implicated in so many different disorders, it makes sense when you understand that it affects such fundamental and essential parts of our bodies– our guts and our immune systems.

Now that we have covered some more details about gluten and its effects, let us go back to the IBS study discussed earlier.

For the study, participants were selected who reported having IBS symptoms that were helped by a gluten-free diet. They were first put on a low-FODMAP diet. After two weeks, participants then had varying amounts of gluten and/or whey protein added to the diet. FODMAPs are a type of carbohydrate that is poorly absorbed by the body and is instead broken down by microbes in the gut. FODMAPS are in countless foods: fruits and vegetables, grains and beans, artificial sweeteners, and dairy.

One of the things the researchers found was that participants’ symptoms improved on the low-FODMAP diet, and then symptoms worsened on the test diets, no matter how much gluten or whey was added. It is known that there is a powerful connection between the mind and the digestive system, so it is not surprising that participants across the board had worsening symptoms when they thought there might be something harmful being added to their food.

What was surprising to the researchers was that they did not find a consistent response to gluten in particular. They concluded that in the presence of a low-FODMAP diet, gluten might not be a trigger of gut symptoms in that population. This is important information, but it still leaves much more to investigate.

I will just mention a couple of potential confounders. One is that each dietary trial only lasted one week. As other researchers have pointed out, this is likely not an adequate time period. (Eight weeks is recommended for IBS study treatments, and much research indicates that one to six months can be needed for gluten-free interventions to take hold.) Another factor is that people do not typically eat purified gluten; it might have different effects when it is isolated versus when it is part of a food. For example, they mention in the study that gluten might produce symptoms only when paired with FODMAPs. There are many other substances as well, such as wheat germ agglutinin, which are known to have an effect on the digestive tract and which may work in concert with gluten.

Another possibility is that, for IBS patients, gluten is a scapegoat and people feel better only because they are eating fewer of the FODMAPs found in gluten foods. This is the theory that led to the conclusion that gluten sensitivity does not exist. However, even if it is true that gluten is not the direct trigger of the IBS symptoms,  gluten may still be involved in the disease. This is because while FODMAPs have long been identified as a trigger of IBS symptoms, they have not been identified as a cause of IBS. So what is the root cause– what would cause someone to lose the ability to eat something that is ubiquitous in many healthy foods? There is evidence to suggest that gut-damaging gluten could be involved. Even if gluten does not directly cause gastrointestinal symptoms in IBS patients, it could be indirectly causing them through general damage to the gut. The role of gluten is complicated, and it does not act alone, but in spite of this study, there is still evidence that it plays a role in IBS.

There is so much more to gluten than can be encapsulated in an entertaining headline. We do still have a lot to learn about the mechanisms and effects of gluten. However, it remains undeniable that gluten has profound effects on the body, and affects many more people than those with celiac disease. It does not take much searching to find a huge amount of research, both past and ongoing, that attests to that fact. To claim that gluten sensitivity does not exist or that it does not affect a large number of people is simply preposterous.

Stay tuned for my next post, Gluten Intolerance Intolerance (part 2), a short post that touches specifically on gluten and autoimmune disease. Then in part 3 of the series I discuss some troubling aspects of the gluten-free phenomenon, and also look at how something that has been a staple food for millenniums could now be causing so many problems.

A last note: An interesting fact potentially related to the way the IBS study has been portrayed is that Peter Gibson, the head of the lab, published a book last year about a low-FODMAP diet for IBS. This is listed as a conflict of interest in the study. Because he is personally invested in promoting a low-FODMAP diet, Gibson may not be particularly interested in correcting the public perception that his study completely exonerated gluten and found FODMAPs to be the true culprit. I think that a media desperately searching for sensational soundbites is mostly to blame, so I will not speculate here on how much, if any, impact Gibson had on the reporting of this study, but it is interesting.

Research References:

  1. No Effects of Gluten in Patients With Self-Reported Non-Celiac Gluten Sensitivity After Dietary Reduction of Fermentable, Poorly Absorbed, Short-Chain Carbohydrates. Jessica R. Biesiekierski et al. Gastroenterology 2014. http://www.gastrojournal.org/article/S0016-5085(13)00702-6/abstract
  2. Randomised clinical trial: gluten may cause depression in subjects with non-coeliac gluten sensitivity – an exploratory clinical study. Peters SL et al. Aliment Pharmacol Ther. 2014 May;39. http://www.ncbi.nlm.nih.gov/pubmed/24689456
  3. The gluten syndrome: a neurological disease. Ford RP. Med Hypotheses. 2009 Sep. http://www.ncbi.nlm.nih.gov/pubmed/19406584
  4. Gluten sensitivity as a neurological illness. Dr M Hadjivassiliou et al. Journal of Neurology Neurosurgery & Psychiatry 2002. http://jnnp.bmj.com/content/72/5/560.full 
  5. Effectiveness of the gluten-free, casein-free diet for children diagnosed with autism spectrum disorder: based on parental report. Pennesi CM, Klein LC. Nutr Neurosci. 2012 Mar. http://www.ncbi.nlm.nih.gov/pubmed/22564339
  6. Markers of Celiac Disease and Gluten Sensitivity in Children with Autism. Lau NM et al. PLoS One. 2013 Jun. http://www.ncbi.nlm.nih.gov/pubmed/23823064
  7. Gluten- and casein-free dietary intervention for autism spectrum conditions. Whiteley et al. Front Hum Neurosci. 2012. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3540005/
  8. Association of Attention-Deficit/Hyperactivity Disorder and Celiac Disease: A Brief Report. Helmut Niederhofer. Prim Care Companion CNS Disord. 2011. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3184556/
  9. Depressed mood associated with gluten sensitivity—resolution of symptoms with a gluten-free diet. Carr AC. N Z Med J. 2012 Nov. http://www.nzma.org.nz/journal/read-the-journal/all-issues/2010-2019/2012/vol-125-no-1366/letter-carr
  10. The gluten connection: the association between schizophrenia and celiac disease. Kalaydjian AE et al. Acta Psychiatr Scand. 2006. http://www.ncbi.nlm.nih.gov/pubmed/16423158
  11. Maternal antibodies to dietary antigens and risk for nonaffective psychosis in offspring. Karlsson H et al. Am J Psychiatry. 2012 Jun. http://www.ncbi.nlm.nih.gov/pubmed/22535227
  12. Fibromyalgia and non-celiac gluten sensitivity: a description with remission of fibromyalgia. Isasi C et al. Rheumatol Int. 2014. http://www.ncbi.nlm.nih.gov/pubmed/24728027
  13. A Maternal Gluten-Free Diet Reduces Inflammation and Diabetes Incidence in the Offspring of NOD Mice. Hansen CH et al. Diabetes. 2014.  http://www.ncbi.nlm.nih.gov/pubmed/24696449
  14. Remission without insulin therapy on gluten-free diet in a 6-year old boy with type 1 diabetes mellitus. Sildorf SM et al. BMJ Case Rep. 2012. http://www.ncbi.nlm.nih.gov/pubmed/22729336
  15. Stress and the gut: pathophysiology, clinical consequences, diagnostic approach and treatment options. P.C. Konturek et al. Journal of Physiology and Pharmacology 2011.  http://www.jpp.krakow.pl/journal/archive/12_11/pdf/591_12_11_article.pdf
  16. Lectin activity of gluten identified as wheat germ agglutinin. Kolberg J, Sollid L. Biochem Biophys Res Commun. 1985 Jul 31. http://www.ncbi.nlm.nih.gov/pubmed/3839672
  17. Gliadin, zonulin and gut permeability: Effects on celiac and non-celiac intestinal mucosa and intestinal cell lines.  http://www.ncbi.nlm.nih.gov/pubmed/16635908

Other References:

  1. Grain Brain by Dr. David Perlmutter
  2. The Paleo Approach: Reverse Autoimmune Disease and Heal You Body by Sarah Ballantyne, PhD
  3. http://www.marksdailyapple.com/does-gluten-have-any-effect-on-non-celiacs/#axzz3BYsxvv43
  4. https://www.sciencenews.org/blog/scicurious/separating-wheat-chaff-gluten-sensitivity

One thought on “What Is Gluten Sensitivity? (part 1)

  1. Pingback: Gluten Intolerance Intolerance (Part 2: gluten and autoimmune disease) | Edible Update

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