According to Professor Katri Kaukinen, people should not avoid grains if they do not experience any symptoms: a gluten-free diet is not a shortcut to weight loss.
Nevertheless, grains do cause symptoms to some people other than just those suffering from coeliac disease and grain allergies. Such symptoms have been described in research for twenty years but there are currently still more questions than answers.
To be clear from the beginning, grains are not unambiguously bad for you and you should not avoid eating them if you do not experience any problems. Even wheat should not be avoided unless eating it causes pain or discomfort.
“Globally, grains are the basis of people’s diets. Most people eat them throughout their lives without any problems whatsoever. However, for a small part of the population, wheat, barley and rye are not suitable for various reasons,” explains Kaukinen, who is professor of internal medicine at the University of Tampere and researches coeliac disease.
This is true for two groups of people: those suffering from grain allergies and patients with coeliac disease. The mechanisms of these diseases are known, and they can be treated with the right diets.
However, ever since the 1970s there have been reports about a third group whose symptoms resemble those of people suffering from allergies and coeliac disease but who do not fulfil the diagnostic criteria of either. So far, they have been talked about as gluten sensitive, even though it is still too early to tell whether their symptoms are caused by gluten or another compound found in grains.
The first significant study on non-coeliac gluten sensitivity was published in 2011. Professor Peter Gibson’s research group in Australia carried out a strictly controlled study on gluten exposure, which investigated the effects of gluten on adults who had reported experiencing symptoms after consuming wheat. Both coeliac disease and grain allergies had been ruled out for these people.
In the experiment, some research participants were given gluten and others were given a placebo. The researchers even cooked the participants’ meals and carefully selected the indicators used for describing the participants’ symptoms.
The result was that wheat actually caused the symptoms.
“This discovery truly galvanised the academic community. We had previously known that such an illness existed but had no way of helping the sufferers. We might have been able to say that the symptoms were caused by a functional gastrointestinal disorder or irritable bowel syndrome, but were not able to offer any therapies. We were in no man’s land,” Kaukinen explains.
Around 2011, something else happened as well as the publication of the Australian research group’s results: the general public developed an interest in gluten and its effects.
“The media started to circulate stories about how gluten-free diets kept people’s weight in check, gave them shiny hair and even improved their sports performance. The gluten-free diet became trendy.”
It did not take long for the gluten-free diet to become extremely popular.
However, the academic world was simultaneously engaged in discovering ways to help real patients. A group of experts gathered in a round table meeting to find a solution to gluten sensitivity.
“We put our heads together in order to figure out what we already knew and whether we might be able to establish the diagnostic criteria for gluten sensitivity. We also discussed which areas still needed further study.”
The result was a consensus paper published in the peer-reviewed BMC Medicine journal. According to the paper, gluten sensitivity may develop due to mechanisms that are different from coeliac disease and grain allergies. However, what is not known is whether the symptoms are caused by gluten or some other compound found in grains.
“Currently, it is still just a wild guess that gluten is the cause of the symptoms. My question is why don’t we call the symptoms ‘sensitivity to grains’? However, gluten sensitivity is the concept with which we operate largely because the world – the world of academia and the rest of the world – is specifically talking about gluten,” Kaukinen continues.
Since its publication, the article has become one of the BMC Medicine’s most frequently downloaded articles, which means that there is a lot of interest in the issue, both in academia and elsewhere.
However, there remain many unsolved questions. The exact compound causing the symptoms is unknown, and neither is it known if the symptoms are permanent or if they just occur intermittently. Furthermore, it is not known how strict a diet is needed to treat the symptoms.
At the moment, there are no reliable standardised indicators for determining the symptoms. Therefore, the only way to react to gluten sensitivity is still to rule out other conditions as possible causes, after which restricted diets and experiments exposing the patient to various food compounds can be tried.
Several studies on the subject are currently underway. One promising lead came from the United States in the early autumn when a study concluded that the cause of the symptoms may be the weakening of the intestinal wall, which means that microbes and nutrient particles are released into the bloodstream. According to the study, the body responds with an immune reaction, which causes abdominal pain, bloating and diarrhoea.
“The most important finding of this study was to prove that the body clearly reacts to the gluten contained in wheat. The results, which show an increased permeability of the intestinal wall, are also interesting because they indicate that the human body reacts to the bacteria released from the bowel. It could well be that there is less severe damage in the intestines than in coeliac disease and this is why grains cause such symptoms,” Kaukinen says.
These findings are particularly significant for Kaukinen because about a hundred patients who showed symptoms similar to gluten sensitivity were studied at the University of Tampere twenty years ago. Nine per cent were diagnosed with coeliac disease, nine per cent with a grain allergy and the rest of the patients, eighty-two per cent, received no diagnosis.
“About a half of the patients in the study were found to have the same antibodies as in the new study from the United States. The patients also had non-specific inflammation reactions,” Kaukinen continues.
Now those samples have been studied again in the light of the new findings. They show a clear reaction and a publication on the findings is already pending.
Gibson’s own research group has also continued to shed more light on the disease. The group investigated the same cohort as in the study published in 2011 by first putting the patients on the FODMAP diet, in which short chain carbohydrates that are poorly absorbed in the small intestine are eliminated. The diet removed the patients’ symptoms and normalised their situation. Afterwards, some of the participants were given a large dose of gluten, some were given a medium sized dose and some were given a placebo.
The result was that only eight per cent of the patients who had previously reacted to gluten reacted to it again.
“Now the question is whether the FODMAP diet changed the setting or people’s gluten sensitivity varies over time. This study also showed that the case is not closed. It could be that for some reason the intestine has been permeable at some point in time and in those cases the patients should avoid wheat, but sometimes the same patients can tolerate wheat. We need further studies.”
In short, the symptoms caused by grains are real and diagnosed, but there is a “but” – the current hype and fad diets obscure the limit between real symptoms and the trend in avoiding wheat.
“We have patients whom we must help, and health care professionals desperately need guidelines because it is frustrating when they cannot advise their patients.”
However, a gluten-free diet is not the answer to all stomach problems. In addition, restricted diets are always a risk, especially ones that are very strict. Observing a gluten-free diet because it is fashionable or just in case does not help the position of those who have real symptoms. According to Kaukinen, the fad also obscures what is really involved in coeliac disease.
“When more people avoid gluten for whatever reasons, it might give the impression that real coeliac disease patients can still eat a little bit of gluten – that it is sufficient to just mostly avoid it. However, the avoidance of gluten is absolute in coeliac disease and that is why it must be separated from other kinds of dietary choices,” Kaukinen says.
Kaukinen also points out that despite the problems they cause to a minority, grains are rich in nutrients, so they should not be avoided for unsubstantiated reasons.
“People should pay no heed to the hype claiming that a gluten-free diet gives you shiny hair, results in weight loss and makes people do better at sports. If that were true, two per cent of people – all the patients with coeliac disease – would be sporty and thin and have shiny hair.”
What is it all about?
Grain allergies are frequently diagnosed in children. A grain allergy is a disease with many of the same mechanisms as other allergies. The condition usually improves as the child grows older.
Coeliac disease is an autoimmune disease influenced by, among others things, genetics. It is a life long incurable condition that requires a totally gluten-free diet. About two per cent of Finns suffer from this disease.
Gluten sensitivity results in symptoms caused by grains that are not triggered by an allergy or coeliac disease. International estimates of the numbers of gluten sensitive individuals vary from 1.5 to six per cent of the population. Some estimates put the proportion of gluten sensitive individuals as high as 20 per cent. The described symptoms are quite similar to those of coeliac disease and are not limited to stomach problems. Patients have also been described as having skin and joint symptoms and experiencing foggy mind syndrome, another symptom familiar from coeliac disease.
Gluten sensitivity is now being actively studied in different parts of the world. It has been proposed that the symptoms are caused by compounds other than gluten, such as α amylase/trypsin inhibitors (ATIs), which can be found in wheat grains. Grains also have their own bacterial populations, so their connection to human microbiota is also being investigated.
Gluten is a protein contained in wheat, barley and rye.
FODMAPs are a collection of short chain carbohydrates and sugar alcohols that are poorly absorbed in the small intestine. In the FODMAP diet, such carbohydrates are completely or partly avoided. Food items to be avoided include chewing gum, sweets, many fruits that have stones, wheat, barley and rye, beans, onions, mushrooms, some cabbages, and yoghurts with added fibre.
Text: Hanna Hyvärinen
Pictures: Jonne Renvall