Proff that going GLUTEN-FREE could be a total waste of your time AND money
... because only now have scientists discovered the real culprit behind your symptoms — and it’s NOT what you think
Gluten: it’s the sticky protein that gives cake its bounce and bread its chew, but — with sales of gluten-free products soaring — many of us seem to believe we can’t stomach it. the conventional medical view is that gluten, found in wheat and some other grains, won’t cause problems unless, like 1 per cent of the population, you have coeliac disease — a severe immune response to even tiny amounts, that causes inflammation in the bowel and symptoms such as bloating, pain and diarrhoea.
the thinking has been, if you weren’t coeliac, there was little point following a gluten-free diet, particularly as gluten-free foods can be up to four times more expensive.
But it may be a little more complicated than that because — as researchers have observed — for some people with gut problems who test negatively for coeliac disease, going gluten-free genuinely helps.
now experts agree. Cutting out gluten improve symptoms in people who aren’t coeliac — but just not for the reason they think.
In a recent study, researchers at the university of Oslo in norway looked at around 60 people who had chosen to have gluten-free diets despite not suffering from coeliac disease.
they were each told to follow three diets consecutively for seven days: one contained gluten, one contained a type of sugar called fructan, and the third contained neither, all concealed in muesli bars. Results in the journal Gastroenterology showed that fructan triggered more bloating and other gastrointestinal symptoms than the placebo and gluten.
It is the latest in a string of studies to suggest there are other culprits behind what is perceived to be a sensitivity to gluten. In fact, research shows that by going gluten-free, people do inadvertently end up removing the real culprit from their diet, which is what leads to the dramatic improvement in symptoms.
‘When we reviewed the scientific research there was no evidence to say that going glutenfree would benefit anyone other than a coeliac patient,’ says Dr Jessica Biesiekierski, a lecturer in nutrition and gastroenterology at la trobe university in Melbourne, Australia, who has led research in this area.
SO, tO find out what might be behind the symptoms some non- coeliacs seem to experience in response to gluten, Dr Biesiekierski and her colleagues set up a rigorous double-blinded clinical trial, testing 34 patients who claimed to have gluten sensitivity, but who did not have coeliac disease.
Participants were asked to follow a gluten-free diet, but were given identical muffins and bread either with or without gluten to eat daily for up to six weeks. As well as measuring the levels of inflammation markers in the blood, the researchers also monitored gut symptoms such as diarrhoea, constipation and bloating.
the results, published in 2011 in the American Journal of Gastroenterology, showed that nearly 70 per cent of the patients given gluten-containing products suffered symptoms compared with 40 per cent on the fully gluten-free diet, suggesting that gluten really was the source of their problems, even though they didn’t have coeliac disease.
(Participants didn’t know they were really eating gluten, so the researchers were confident the effect wasn’t psychological.)
this, they concluded, might mean some people have a condition they termed ‘ non- coeliac gluten sensitivity’.
then things got more complicated still.
At the same time, Dr Biesiekierski’s colleagues at Monash university in Melbourne, led by respected gastroenterology expert Professor Peter Gibson, were investigating how chemicals called FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) in the diet could trigger symptoms in people with irritable bowel syndrome.
unlike gluten, which is a protein, FODMAPs are sugary molecules that naturally occur in a range of foods, including fruits, vegetables, grains and dairy. the most widespread are fructans, which are carbohydrates found in wheat, fruits and vegetables. Other common FODMAPs include lactose (milk sugar) and polyols, including artificial or naturally- occurring sweeteners such as xylitol and sorbitol.
For most people, FODMAPs are a normal part of a healthy diet. they are fermented by the ‘good’ bacteria living in the bowel and help to absorb water into the stools. However, this process of fermentation can trigger unpleasant symptoms including bloating, pain and diarrhoea in some people — exactly the same symptoms experienced by non-coeliacs who appear to be gluten-intolerant.
the Monash team started measuring the levels of FODMAPs in food and found that many grains with high gluten, such as wheat, also tended to be high in fructans, while commercial glutenfree bread and pasta had very low levels of fructans and other FODMAPs. this explains why people with FODMAP sensitivity tend to see an improvement in their symptoms when they switch to gluten-free products.
to confirm this link, Dr Biesiekierski and her colleagues at Monash ran a second clinical trial. nearly 40 patients were asked to eat a low-FODMAP diet for two weeks leading up to the trial, then received a week’s worth of specially prepared meals containing gluten, FODMAPs or neither.
By testing every patient on each of the three diets separately and carefully monitoring their symptoms, the researchers were able to tease apart the real culprit. ‘All our patients believed they were gluten sensitive and that their symptoms improved on a glutenfree diet,’ says Dr Biesiekierski.
‘ But every single person improved more on the FODMAPFOR
free diet. Then, when we gave them gluten without them knowing, 90 per cent of them had no symptoms of intolerance.’
In other words — it’s not sensitivity to gluten, it’s a reaction to FODMAPs that is causing the problem.
The biological cause of FODMAP sensitivity remains unknown. It can only be formally diagnosed by cutting out certain foods under the supervision of a registered dietitian for up to six weeks. (Dr Biesiekierski cautions against starting any kind of restricted diet without medical supervision.)
BecAuse
FODMAPs encompass a large group of chemicals and are found in so many different foods, a low-FODMAP diet can be very restrictive. But unlike coeliac disease, where every speck of gluten must be permanently eliminated, there are many different FODMAPs, and each sufferer will have a spectrum of sensitivity.
This means most people find they can reintroduce limited quantities of many foods into their diet once their key triggers have been identified.
Awareness of the low-FODMAP approach is growing across Australia. supermarkets there are starting to stock products labelled as low in FODMAPs, alongside more common gluten-free items, and Dr Gibson’s team at Monash university has developed the Low-FODMAP Diet smartphone app.
While reducing FODMAPs may be the solution for many people with bowel problems, David sanders, a professor of gastroenterology at the Royal Hallamshire Hospital and the university of sheffield, says coeliac disease shouldn’t be overlooked.
‘For every one person with coeliac disease, there are three walking around undiagnosed,’ he warns. ‘If you suffer recurrent bloating, pain or diarrhoea, go to your doctor.’
In some cases, it is also possible to have the condition without symptoms at all (see panel, right).
‘But if you don’t have coeliac disease or FODMAP sensitivity, there’s no need to cut out foods,’ adds Professor sanders. ‘There’s no evidence that eating gluten-free is better for you if you’re not genuinely sensitive.’
‘There’s no doubt in my mind that cutting out FODMAPs is one option for people with bowel symptoms, and it’s wonderful to have dietary interventions rather than taking pills for it, but they must be used appropriately.’