I find it very commendable when the general public gets interested in their diet and actively seeks our information about which foods are good for their body and which are not. The problem is, not all information they find is correct and substantiated with science. Food science and nutritional science are legitimate disciplines – scientists carefully design experiments to find out what effect various foods and substances have on human health, and they are also quick to follow trends in consumer preferences with new research. With the rapid growth in gluten-free diet popularity among normal population (that is, people who do not objectively suffer from coeliac disease or wheat allergy), there has been research effort to find out whether it is just a fashion or if not consuming gluten can really have beneficial effect on our health. In this article, I would like to give you an overview of their findings. If you think there are some gluten-related hypothesis I failed to include, mention them in comments and I will look into them when I have time. I’m also very much open to opposing views, provided it is substantiated with real science. And lastly, feel free to re-post and translate.
What is Gluten?
Gluten is a summarizing name for a group of proteins present in wheat, barley and rye. Because of the abundance of certain nitrogen-rich amino acids in these proteins, they serve as a source of nitrogen and carbon for the germinating seed. In terms of production of bakery goods, gluten proteins are responsible for the dough-forming properties of wheat-based flour, as they form an elastic cross-linked matrix when water is added and simply said, they help to keep the dough together and elastic1. This also explains why gluten-free products tend to have a more crumbly structure, as they lack proteins that would give it cohesiveness and elasticity.
3 Types of Gluten-Related Disorders
Celiac Disease (CL)
Celiac disease is an immune system-mediated disease affecting approximately 1% of population worldwide, though it is speculated that the occurrence is slightly increasing, with discussion about whether this increase means simply more reported cases or a real increase of the disease. It is triggered by specific gluten proteins which cause an immune response resulting in inflammation in the small intestine. The disease is pretty well understood and individuals suspecting they may have this disease can be tested to confirm or rule out such diagnosis2.
Wheat Allergy (WA)
A not very well understood disorder, wheat allergy is for the time being classified as food allergy, with similar symptoms to other food allergies. The molecular mechanism is not yet well explained, but might be related to specific structural characteristics of gluten proteins2.
Non-Celiac Gluten Sensitivity (NCGS)
NCGS is a disorder manifested through various physiological and psychological symptoms in people who do not have CL or WA, and whose symptoms are alleviated when gluten is excluded from their diet2, 3. Despite the name, new research shows that NCGS sufferers also negatively respond to other components of wheat, such as other proteins, fermentable saccharides and polyols. NCGS manifests with symptoms related to both the gastrointestinal tract and other parts of the body (muscle/joint pain, fatigue, rash, anxiety/depression, headache…). NCGS is believed to be more common than CD, but the prevalence is not well defined yet and the mechanisms by which it is caused are not well known either. One study found prevalence of 0.55%4. Other sources estimate the prevalence in the US to range between 1 and 6% of the population5, though some estimates went as high as up to 15%. To add more confusion, some authors argue whether NCGS existence is even substantiated2.
There has been research trying to understand more about this disorder and gluten. One study suggested there might be a link between “depression”, or rather pessimistic mood and gluten ingestion, but the researchers admitted themselves that the study had many limitations3. Another study showed that self-reported NCGS people did not respond to gluten in diet in a particular way once all other potential sources of response were eliminated2, which may however also mean that it is other components of wheat that are responsible for the disorder, such as the above mentioned saccharides, polyols or other proteins.
Basically, both CD and AW are quite easily detectable by doctors. However, NCGS, as it is yet to be well-defined and understood, is often a subject of self-diagnosis.
One qualitative study compiled several points which seem to be common for many people who have never been formally diagnosed with CD or WA. (The study was conducted in America, and is therefore linked with the “typical American diet” and USA healthcare system.) These are:
- Distrust in doctors because the diagnosis and medication failed to alleviate their symptoms, and belief that doctors are only interested in treatment related to using commercially interesting drugs;
- Belief that going gluten-free rid them of issues such as being overweight, tired, slow, depressed and generally unwell, having stomach pain and generally feeling better than when they ate gluten;
- Preference for alternative, non-science-based therapies;
- Tendency (in about 1/3 of participants) to diagnose others with gluten disorders not based on any scientific evidence (mostly with the self-perception of wanting to help others)6. However, are they right? Above, I showed that NCGS prevalence is estimated to be at most 15%2, yet some of gluten-free advocates claim that while approximately 1 in 130 people has celiac disease, 120 in 130 should avoid gluten6 – apparently just because.
Gluten-free Is Also a Good Business
While it may seem that companies producing gluten-based products are the bad guys that should be lumped together with things like potato crisps and instant soups; and gluten-free are the good saviors concerned with people’s health, this is quite a naïve thinking. Gluten is nowadays a very emotive subject, with more people feeling anti-gluten than pro-gluten (or gluten-indifferent). Also, as gluten-free market is estimated to be around 15 – 20% of the population, celiacs constitute a minor part of it2. Even if NCGS constituted 15% (which is not the most realistic estimate), there are still 5% that have no medical reason to avoid gluten. From a new food product developer’s point of view, supporting the gluten paranoia while designing one gluten-free product after another is a great way to make more money and take market share from gluten-containing products. A large amount of my FIPDes classmates designed gluten-free products for the New Food Product Development Class, too. Celiacs are a small part of the society – while the offer of gluten-free is still much smaller than the gluten-containing one and therefore there are many opportunities for new product introduction, the size of the market has limitations. Therefore, persuading even gluten-tolerant people to go glu-free is a pretty good (and currently easy) business. So yes, people and companies have a good reason to go against gluten, and that reason is sometimes/often money, not concern for your health.
Gluten and Type 1 Diabetes
There are links between Type 1 Diabetes and Gluten, however the relationship is not as simple as some articles make it seem. First of all, it has been shown that celiac patients consuming gluten have higher incidence of T1 diabetes than those who were diagnosed early and had gluten-free diet for longer7.
One study showed that gluten in mice feed led to the mice developing diabetes more often than gluten-free fed mice, from the description I assume that these mice were otherwise normal mice (not celiac). The mechanism suggested was change in gut microflora. However, the study clearly states that more experiments are needed to confirm the hypothesis7. My concern with the study would be that the amount of gluten in the diet of some mice was not mentioned and there was no information as to whether the amount of gluten in the diet was within normal amounts. Moreover, another study with comparable mice found that both gluten-free AND gluten-enriched diet leads to diabetes prevention8. Yet other experiments also showed that the amount of gluten in the diet and also the time when it is introduced plays a role in diabetes development in mice9. Also, the effect of diet in humans on diabetes is more complicated. It was shown that OVER-consumption (hence my concern with amount of gluten in the mice diet) of gluten and other foods and reduced intake of fruit and vegetables can lead to detrimental effect on microbiota and development of diabetes9, 10. Viruses and other pathogens, as well as genetic predispositions also most likely play a role in diabetes development9. As you can see, the research about gluten’s role in diabetes in non-celiac individuals is very inconclusive and needs much more research before final verdict can be made.
Gluten and Obesity
No relationship was found between whole-wheat diet and obesity11.
How About the Good Things You Might be Missing Out by Going Glu-free?
No gluten means no wheat, and wheat can be pretty good. Research suggests that not all whole-grain is the same – it seems that components of wheat bran and wheat whole grains can prevent colon cancer better than non-wheat grains such as oats12.
So What Should You Do If You Do Not Suffer from Gluten (or Wheat) Related Disorder, or You’re Not Sure Yet?
Gluten-free foods do not have better nutritional properties and are not healthier than their gluten counterparts, unless other aspects have been changed as well. Some of the improvement in people who went for gluten-free diet have been attributed to factors that are actually not related to gluten. For example, gluten-free diet often requires lowering of bakery goods in the diet in general (since gluten-free is expensive and still harder to find than gluten-containing products) and increase in fruits and vegetables. It is also linked to eating less processed food and fast food and to caring more about diet and health in general. And finally, there is also the possibility of placebo effect occurring, especially with hard to diagnose psychological symptoms.
A good recommendation for everybody who does not have CD or AW would be to first adhere to strictly healthy diet (varied, plenty of fruit and vegetables, reasonable amount of lean meat, fatty sea fish and other marine organisms, getting enough vitamins and minerals, not overeating carbohydrate-rich food, preferring wholegrain products, cutting down on sweets, savory snacks, fast food and overly sugary/salty processed foods…). Only if this diet does not lead to improvement of symptoms, try gluten-free diet and see if it makes a real difference5.
And in any case:
1) Do not blindly believe information you find on the net if it does not provide real evidence. Real evidence are well-designed studies conducted by scientists and doctors which critically evaluate their results and which are published in peer-reviewed journals. Real evidence is not your neighbor’s or favorite blogger's personal experience or random articles on websites.
2) Do not act as a doctor and persuade people to go gluten-free without evidence that it will help them (and no, just because it helped you does not mean it will help everybody even if their symptoms are similar – same symptoms can still have different causes).
Since repetition is the mother of wisdom, as we say in Bohemia, here are the 7 take-home points of this article:
- There quite probably is a gluten, or more likely, wheat-related disorder (Non-Celiac Gluten Sensitivity) which is neither celiac disease nor wheat allergy, it has a wide range of symptoms and it was proven (well OK, there is still some doubt) that there are physiological changes in response to presence or absence of gluten.
- This newly described disorder is more prevalent than celiac disease, but most likely with prevalence somewhere between 0.55% and 6%, at the very most 15%. This means that at most 3 in 20 people have it.
- People who do not have any of the 3 described diseases will not have any benefit at all from omitting gluten from their diet, unless they make other dietary and lifestyle changes as well and unless they are subject to a placebo effect.
- Gluten is NOT related to obesity and type 1 diabetes, based on currently available evidence.
- Wheat whole grain constituents may protect against colon cancer better than other grains.
- Gluten free is a pretty good business for food companies too.
- If you’re not a gluten related disorder sufferer, then as with everything, moderation may be a good way to think about gluten. Eat wholegrain bakery goods, consumer different grains (yes, including wheat) and eat a healthy and balanced diet.
1. Coultate TP, Tom PC. Food: the chemistry of its components: Royal Society of Chemistry Cambridge,, UK; 2002.
2. Biesiekierski JR, Muir JG, Gibson PR. Is Gluten a Cause of Gastrointestinal Symptoms in People Without Celiac Disease? Current Allergy and Asthma Reports. Dec 2013;13(6):631-638.
3. Peters SL, Biesiekierski JR, Yelland GW, Muir JG, Gibson PR. Randomised clinical trial: gluten may cause depression in subjects with non-coeliac gluten sensitivity - an exploratory clinical study. Alimentary Pharmacology & Therapeutics. May 2014;39(10):1104-1112.
4. Caio G, Volta U, Tovoli F, De Giorgio R. Effect of gluten free diet on immune response to gliadin in patients with non-celiac gluten sensitivity. Bmc Gastroenterology. Feb 2014;14:7.
5. McCarter DF. Non-Celiac Gluten Sensitivity: Important Diagnosis or Dietary Fad? American Family Physician. Jan 2014;89(2):82-+.
6. Moore LR. "But we're not hypochondriacs": The changing shape of gluten-free dieting and the contested illness experience. Social Science & Medicine. Mar 2014;105:76-83.
7. Marietta EV, Gomez AM, Yeoman C, et al. Low Incidence of Spontaneous Type 1 Diabetes in NonObese Diabetic Mice Raised on Gluten-Free Diets Is Associated with Changes in the Intestinal Microbiome. Plos One. Nov 2013;8(11):9.
8. Funda DP, Kaas A, Tlaskalová‐Hogenová H, Buschard K. Gluten‐free but also gluten‐enriched (gluten+) diet prevent diabetes in NOD mice; the gluten enigma in type 1 diabetes. Diabetes/metabolism research and reviews. 2008;24(1):59-63.
9. Barbeau WE. What is the key environmental trigger in type 1 diabetes - Is it viruses, or wheat gluten, or both? Autoimmunity Reviews. Dec 2012;12(2):295-299.
10. Bengmark S. Gut microbiota, immune development and function. Pharmacological Research. Mar 2013;69(1):87-113.
11. Brouns F, van Buul VJ, Shewry PR. Does wheat make us fat and sick? Journal of Cereal Science. Sep 2013;58(2):209-215.
12. Zoran DL, Turner ND, Taddeo SS, Chapkin RS, Lupton JR. Wheat bran diet reduces tumor incidence in a rat model of colon cancer independent of effects on distal luminal butyrate concentrations. The Journal of nutrition. 1997;127(11):2217-2225.