Thursday, May 22, 2014

Does gluten sensitivity exist?

Last week, articles took the internet ablaze questioning whether gluten sensitivity exists.  Multiple articles written by multiple people claimed gluten sensitivity doesn't exist, including this one titled, Researchers who provided key evidence for gluten sensitivity have now thoroughly shown that it doesn't exist.  These articles take a look at a study published last year that had some very interesting findings, they just didn't find that gluten sensitivity doesn't exist.  In fact, it found the opposite, that it does exist.  However, the study raises questions on those who see improvements in GI symptoms on a gluten free diet.  Those findings are:
  • Gluten may not be the primary trigger in grains that induces GI symptoms in susceptible individuals
  • Most of the people who improve on a gluten free diet may be responding to reduced FODMAPS and not less gluten
  • Gluten sensitivity is poorly defined and the criteria for diagnosis is terribly inaccurate
Let's take a look at the study to see what we can pull from it.  The study happened in 2 parts.  In the first part, the authors followed 37 people with non-celiac gluten sensitivity(NCGS) and IBS but not Celiac disease through 3 different diets that followed 2 weeks of reduced FODMAP intake.  FODMAPs are fermentable carbohydrates that humans cannot digest but resident bacteria in the digestive tract can.  The 3 diets contained either gluten only, gluten and whey, and whey only and each person underwent each diet for 1 week.  They tested the subjects for intestinal inflammation and immune system activation as well as a subjective assessment of fatigue.  In this part of the study, gluten specific effects were found in 3(8%) of the participants, and symptoms improved during reduced FODMAP intake but worsened when gluten OR whey were introduced in subjects.

In the second part of the study, 22 subjects were given diets that increased FODMAP intake and included either gluten, whey, or no additional protein for 3 days and subjectively assessed for GI symptoms.  All subjects received all 3 diets.  This part of the study found that GI symptoms increased by similar levels in all groups with no specific response to gluten.  However, there was an order effect which means that the order that a person received each diet had an effect on the results.  In other words, people who received the diet with gluten first all had similar results to one another but different results than people who had whey or no gluten first.

So what does this study show?  First off, this study supports the notion that NCGS exists, but that only a small number of people who respond positively to a gluten free diet are responding to lower gluten exposure.  Instead, they may be responding to a reduction in FODMAP intake.  But what does that mean?

First off, NCGS is poorly defined.  To be diagnosed with NCGS you simply have to have symptoms of gluten sensitivity, not have celiac disease, and see an improvement in your symptoms with a gluten free diet.  So anyone who has IBS or other GI problems who responds positively to removing gluten qualifies.  There are 2 problems with this.  The first problem is that a gluten free diet can mean many things.  For some people it means removing grain-based foods, for others it means removing the gluten from grain-based foods.

If the culprit is specifically gluten, either one should work.  The problem is, if it's not gluten and as this study suggests FODMAPS that are the problem for most people with GI symptoms, removing grain-based foods would be a successful approach while consuming grain-based foods with the gluten removed would have little effect since they would still contain FODMAPs.  But why are FODMAPs a problem?  The answer potentially lies in something called small intestinal bacterial overgrowth, or SIBO.

SIBO is a condition where bacteria overgrow in to the small intestine.  While the large intestine houses a large number of bacteria, the small intestine houses far fewer in comparison.  When an excessive amount of this bacteria begins to take up residence in the small intestine, people experience the same IBS symptoms associated with NCGS.  In fact, some studies put the number of people with IBS who also have SIBO at approximately 80%(1, 2).  Furthermore, those who eradicate SIBO see dramatic improvements in their symptoms(2).  While there is a simple test for SIBO, the authors of the study did not test for it.  This is ironic since FODMAPS should exacerbate SIBO and IBS symptoms by providing substrate for bacteria that make their way in to the small intestine to ferment, causing bloating and gas.

The second problem that was not tackled directly in this study was gluten sensitivity that presents with symptoms outside of the GI tract.  Though gluten sensitivity and Celiac disease are both associated with GI symptoms, Celiac disease presents itself most typically with symptoms outside of the GI tract(3) and gluten sensitivity often presents itself with neurological symptoms and no GI symptoms(4).  The brain is one of the most common sites for symptoms related to gluten sensitivity including headaches, brain fog, vertigo, and more(3).  This study only looked at people with symptoms of IBS and suspected gluten sensitivity and left out people who may fit the criteria of gluten sensitivity with no GI symptoms.  So people who see relief from vertigo, headaches, rashes, or any other manifestation of NCGS without IBS were not included in this study so the results don't pertain to them.

So what can we pull from this study?  In the majority of people with symptoms of IBS and self-diagnosed gluten sensitivity, their GI symptoms may be caused by FODMAPS and not gluten.  This does not rule out that they are sensitive to gluten as gluten sensitivity can present itself with symptoms outside of the GI tract, and it certainly doesn't rule out the existence of gluten sensitivity in the population since the study showed 8% of the subjects had gluten specific effects.  The good news here is that a large chunk of people who think they are sensitive to gluten may have SIBO which is something that can be improved with a low FODMAP diet.

On the other side of the coin, people who eat a gluten free diet that contains grain-based foods with the gluten removed who still experience GI symptoms may want to look at reducing FODMAP intake as well.  Dropping grains altogether as well as legumes and a few other fruits and vegetables for a brief period, as is seen in the specific carbohydrate diet, may fix the problem if SIBO is the culprit.  Once the issue is fixed, a normal diet can resume.


Most of these articles professing that NCGS doesn't exist are sensationalizing the research that they use to try and support their preconceived notion.  This study showed that most people who have self-diagnosed themselves with NCGS based on symptoms of IBS are not experiencing GI symptoms due to gluten.  This is backed up by a study published earlier this year that found that only 1 in 4 people who self-diagnosed themselves with NCGS fit the criteria for diagnosis(5).  Oddly the author of the article mentioned at the beginning of this blog took that as evidence that gluten sensitivity doesn't exist, which isn't the case.  It doesn't surprise me that most people who self-diagnose themselves with gluten sensitivity don't have it.  I'd imagine most people who self-diagnose themselves with aggressive colon cancer on WebMD don't have that either.

If you learn anything from this study, it's that you should see a doctor rather than self-diagnose yourself with anything.  Another thing you should pick up from the hoopla surrounding these articles based on a study is that the authors are trying to get clicks, they're not trying to be accurate.  The title Gluten sensitivity doesn't exist is likely to grab more attention than Gluten sensitivity exists but maybe less than we thought because it will grab the attention of both people who have already decided it doesn't exist and people who have benefited from a gluten free diet.  More clicks equals more $$$.  It doesn't help that so few people even check the sources these authors cite in their work.

The final thing you should take home is that we are in the embryonic stages of gluten research, a knee jerk reaction based on a few bloggers' incorrect opinion of a study that didn't show what they say it showed isn't going to change the science.  All it does is give you an incorrect opinion that goes against what the research and MDs working in this field are seeing on a day to day basis.  Spreading it on social media without checking that it's accurate only increases the confusion and doesn't do a service to anyone.

As the research progresses I'm sure there will be further refinement since the criteria for diagnosis is so crude.  This means that some people who are undertaking a gluten free diet may learn that gluten isn't a problem and their issue may be a much simpler fix that will allow them to eat foods they thought weren't right for them.  I don't see how that's a bad thing, even if you don't want to eat gluten regularly I don't see why having the option is something you should preoccupy yourself with.  On the flip side, if you don't believe gluten sensitivity exists, why not pick up some peer reviewed journals and read them?  The internet isn't peer reviewed so any yahoo with a computer can print something and send it out to cyberspace, I'm living proof of that.  :)

Confused about gluten?  The dude who is the go to guy on gluten research just wrote a book that I referenced in this article and it clears up a lot of the confusion about the research.  Take a look...

Gluten Freedom by Dr. Alessio Fasano