Asked to sprinkle two types of flour on pasta and soup for 10 days at time
One was gluten-free and the other contained gluten and participants were asked to record their symptoms during each 10-day experiment
Then asked to identify which flour had gluten – two-thirds got it wrong
Suggests many people are wrongly following gluten-free diets, experts say
The majority of people who fear they have an intolerance to gluten could be mistaken, scientists have found.
Just one-third of people who believed they have non-coeliac gluten sensitivity (NCGS) were found to suffer symptoms connected to an intolerance, a new study found.
Gluten is a protein found in wheat and related grains, including barley and rye.
It gives elasticity to dough, helping it to rise and keep its shape, and is often responsible for making the final product chewy.
It is thought there are now more people following a gluten-free diet, after self-diagnosing their own gluten intolerance, than those diagnosed by a doctor with coeliac disease.
A new study has found that just one third of people who believe they have non-coeliac gluten sensitivity actually suffer the adverse symptoms of eating gluten, a protein found in wheat and other grains, including rye
While coeliac disease – where a person suffers an adverse reaction to gluten – can be diagnosed via a blood test, there exists no diagnostic test for NCGS.
It has led many doctors to remain sceptical as to whether the condition is a legitimate one.
Indeed, the study authors note ‘currently, its existence remains controversial’.
They add: ‘If it does exist, its cause and prevalence are unknown. The name NCGS implies that gluten is the trigger for the reported symptoms.
‘However, other components in cereal could be responsible.’
Researchers set out to assess the prevalence of non-coeliac gluten sensitivity in a cohort of patients without coeliac disease or wheat allergy, while fulfilling the accepted clinical criteria for NCGS and who were following a gluten-free diet of their own accord.
The study, led by a team of gastroenterologists from the University of Brescia, and Spedali Civili of Brescia in Italy, involved 35 volunteers.
All had been diagnosed with non-coeliac gluten sensitivity (NCGS) and had been following a gluten-free diet for six months prior to the trial starting.
Researchers performed two experiments on 35 volunteers, who all had non-coeliac gluten sensitivity.
They were asked to sprinkle two different types of flour, one containing gluten and a second that was gluten-free, on to pasta and soup for 10 days, in two separate blocks
Researchers asked the participants to complete a series of experiments involving gluten-free flour, and another flour containing gluten.
Volunteers were given two sachets, labelled ‘A’ and ‘B’, each containing 10g of flour.
For the first stage of the study, the volunteers were given one type of flour and told to sprinkle it over pasta or soup once a day for 10 consecutive days.
A two-week break ensued where the participants were told to return to there normal, gluten-free diets.
Then, for the second 10-day period they were given the second sachet of flour, and told to repeat the experiment, using the second type of flour.
The results showed two-thirds of those taking part recorded no adverse symptoms when eating the gluten-containing flour, and wrongly picked out the gluten-free variety
Throughout the two 10-day experiments the study participants were asked to report any symptoms of pain, reflux, indigestion, diarrhoea and constipation, using a rating scale of one (no adverse effects) to seven (severe adverse effects).
At the end of the two experiments, the volunteers were asked to guess which flour contained gluten.
If they guessed correctly, and their side-effects linked up with the reality of type of flour they had been eating, they were classified as having NCGS, regardless of any prior diagnosis.
The study’s authors said: ‘We found evidence from our study to support a diagnosis of NCGS in only a third of patients who met internationally recognised criteria for its diagnosis.
‘However, two-thirds of the participants were unable to correctly identify the flour containing gluten.’
They said almost half the participants wrongly identified the gluten-free flour as being the flour that contained gluten.
They recorded their symptoms as being worse after the gluten-free flour part of the experiment, but not after eating the flour containing gluten.
The authors said the explanation for this is ‘unclear’.
They suggest these volunteers may be sensitive to a component in the flour, besides gluten.
Just under a fifth of the participants in the study, were unable to distinguish between the two flours, and did not record any worsening of symptoms with either challenge.
‘These findings suggest that the symptoms they experience when exposed to gluten-containing food in normal life, is related to a psychological anticipation of intolerance,’ the authors note.
‘This appears to be a nocebo effect.
‘Emotional factors and commercial pressure may be important, even in patients with low levels of somatisation.’
In conclusion, the authors said: ‘The distinction between these patient groups is important clinically, as only patients with NCGS need to adhere strictly to a gluten-free diet.’
Source: Daily Mail
