The Melbourne professor who found links between gluten and gastrointestinal distress has discovered that his original findings were flawed, casting doubt on the validity of non-coeliac gluten intolerance.
According to Real Clear Science, Peter Gibson, a professor of gastroenterology at Monash University and director of the GI unit at The Alfred Hospital in Melbourne, published a study in 2011 that found gluten caused gastrointestinal discomfort in patients that didn’t suffer from Coeliac Disease.
His research was one of the strongest pieces of evidence that non-coeliac gluten sensitivity, or gluten intolerance, exists, and has prompted the surge in gluten-free products on retailers’ shelves in recent years.
According to Innova Market Insights, nearly eight percent of global product launches recorded in 2013 used a gluten-free positioning, rising to 10 percent in Western Europe and nearly 14 percent in the USA, where gluten-free products are estimated to be worth $15 billion by 2016, a rise of 50 percent compared to the 2013 figures.
Despite the wide acceptance of Gibson’s findings, they shed no light on what causes some consumers’ adverse reaction to gluten, and he had uncovered more variables to control, so he decided to reassess his findings.
This time he provided his subjects with every single meal throughout the experiment’s duration and all other potential dietary triggers including lactose, preservative such as benzoates and sulfites and poorly absorbed short-chain carbohydrates (FODMAPs) were removed. Nine days’ worth of urine and faecal matter were also collected.
All 37 of the experiment’s participants didn’t have Coeliac Disease but did experience improved gastrointestinal symptoms on a gluten-free diet. They were first fed a low FODMAP diet, then trialled a number of other diets including one with 16g per day of added gluten, one with 2g of gluten and 14g of whey protein isolate and one with 16g of whey protein isolate (this was the placebo).
The participants didn’t know which diet they were eating at any stage of the experiment.
Interestingly, Gibson found that regardless of which diet the participants were eating, they reported a worsening of gastrointestinal symptoms to similar degrees. Therefore, Gibson’s revised study found that gluten intolerance may be more psychological than anything else.
“The data clearly indicated that a nocebo effect, the same reaction that prompts some people to get sick from wind turbines and wireless internet, was at work here. Patients reported gastrointestinal distress without any apparent physical cause,” Real Clear Science reports.
“In contrast to our first study… we could find absolutely no specific response to gluten,” said Gibson.
The real culprit could be FODMAPs, said Jessica Biesiekierski, a gastroenterologist formerly at Monash University and lead author of the study alongside Gibson, who noted that when participants consumed the low-FODMAP diet, almost all reported that their symptoms had improved.Gluten may well have been incorrectly identified as the cause of gastrointestinal distress in non-coeliac consumers because some of the largest sources of FODMAPs, specifically bread products, are removed on a gluten-free diet, which could explain why those who suffer from symptoms including bloating, wind and nausea feel better while following a gluten-free diet.