Professor Peter Gibson and his team set out to determine whether gluten causes problems in people who do not suffer from coeliac disease. The team found that short-chain carbohydrates called FODMAPs, not gluten, might be triggering symptoms such as bloating and stomach pain. The results have put some scientifically valid findings in this controversial area.
Photo credit: James Braund
Dr Jane Muir
Dr Jessica Biesiekierski
Ms Simone Peters
Dr Evan Newnham
Dr Greg Yelland
Dr Jacqueline Barrett
Mrs Ourania Rosella
About 11 per cent of Australian adults follow a gluten-free diet. Less than 0.5 per cent does this for diagnosed coeliac disease.1
Non-coeliac gluten sensitivity is an internationally-recognised condition, but remains highly controversial with its prevalence stated to be between 0.6 and 6 per cent of the population across the Western world.2
Gastroenterologist Professor Peter Gibson set out to tackle the big issue of whether gluten causes problems in people who do not suffer coeliac disease.
“Many claims were being made by scientists and non-scientists alike without good evidence.
“We performed a ‘gold-standard’ randomised, blinded cross-over, multi-dose re-challenge study,” Professor Gibson explained.
The team developed infrastructure to perform this high-quality dietary study without multiple uncontrolled confounders.
Throughout the study, all meals were provided to 37 participants who had self-diagnosed non-coeliac gluten sensitivity and irritable bowel syndrome.
The participants alternated through gluten-free and low and high gluten diets.
To ensure there were no other possible confounders, the diets were all low in FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols) a type of short-chain, poorly absorbed carbohydrate that can induce abdominal symptoms.
The study provided the first randomised, controlled data in a re-challenge study about whether gluten might indeed be responsible for inducing gut symptoms in people who do not have coeliac disease.
The team found that FODMAPs, not gluten, might be triggering gut irritability.
"We do hope that our findings dampen enthusiasm for gluten-free diets."
“We demonstrated that gluten, without FODMAPs, did not specifically induce symptoms in patients who believed they were gluten intolerant.
“Indeed, all patients experienced reduced gut symptoms in the run-in period when they, for the first time, restricted all FODMAPs in their diet.
“We found no changes in the physiology of the gut in response to gluten,” Professor Gibson remarked.
The research demonstrated how nutritional and dietary studies should be performed if meaningful results are to be obtained.
“Methodological weaknesses and poor data interpretation remain major obstacles to continuing progress in general thought in this area,” Professor Gibson noted.
The findings have put some scientifically valid findings in a controversial area and have been pivotal in putting brakes on the glutenfree epidemic that is sweeping the world. Three large studies have since been performed and published with similar results.
Despite the results, most patients continued on a gluten-free diet because ‘they felt better’. However, the team hypothesised that this was not because the gut symptoms improved, but because their psyche did. In a pilot blinded, placebo-controlled re-challenge study, they found that gluten was associated with greater feelings of depression, despite not getting more abdominal symptoms.
Professor Gibson and his team will endeavour to understand more about how gluten affects the body, including whether gluten influences cognitive function or psychological health and, if so, whether this affects just susceptible people or if it is an issue across the general population.
Gluten: villain or scapegoat?
Gluten – a sticky protein found in wheat, barley, and other grains – has become a food villain in recent years. It has been blamed for a range of symptoms including bloating and flatulence, anaemia, tiredness and irritability, and joint pain and inflammation. Many people believe that avoiding gluten is essential to a healthy lifestyle and they avoid gluten to alleviate gut symptoms or fatigue. Yet, there is little scientific evidence to support these claims.
Sales of gluten-free foods have skyrocketed, despite often being costed at a premium price. In the USA, sales of gluten-free foods reached approximately $10 billion in 2013,3 with most of the increased demand for gluten-free foods from those who have not been clinically diagnosed coeliac disease. A rapid growth in the sale of gluten-free foods has also been observed in the UK and Australia.
1 Golley S, Corsini N, Topping D, et al. (2015) Motivations for avoiding wheat consumption in Australia: results from a population survey. Public Health Nutr 18, 490-499.
2 Molina-Infante J, Santolaria S, Sanders DS, Fernández-Bañares F. Systematic review: noncoeliac gluten sensitivity. Aliment Pharmacol Ther. 2015 May;41(9):807-20.
3 NPD Group (2015) Percentage of U.S. Adults trying to cut down or avoid gluten in their diets reaches new high in 2013, reports NPD.