1. First things first: coeliac disease* is a real thing, where eating food containing gluten causes an adverse reaction.
Around 1% of people in the UK have coeliac disease, but many others go gluten-free for health reasons. There’s a huge industry around gluten-free foods. The market is currently worth £175m and is expected to reach £561m by 2017.
In people with coeliac disease, the immune system mistakes substances found inside gluten as a threat to the body and attacks them. This damages the person’s intestines and makes it hard for the body to absorb nutrients from food.
*or “celiac disease” if you’re American and pedantic.
2. But gluten intolerance in the absence of coeliac disease is starting to look a little more suspect.
But last year Gibson published a follow up paper based on a new, much more detailed and controlled, study that contradicts his previous findings.
That doesn’t mean the symptoms people who think they’re gluten intolerant are experiencing are all in their head. It just means it could be something other than gluten that’s causing them.
3. Gluten sensitivity could be a misnomer for allergies related to things other than gluten in wheat.
“There are many people that feel that they have gluten sensitivity because when they go on a gluten-free diet they feel well, and when they eat wheat they feel poorly,” Gibson told the Gastroenterology podcast last year. But the question is whether it’s really the gluten or another part of wheat that is making people feel unwell.
4. Wheat has both protein and carbohydrate components, and either could be to blame.
Proteins other than gluten could be to blame for symptoms experienced by patients who think they’re gluten sensitive.
Gluten breaks down into smaller proteins gliadin and glutenin when we digest it. It’s gliadin that people with coeliac disease have a problem with. But these two also break down further into even smaller proteins, and these smaller ones could act like morphine or other opiates, possibly explaining the lethargy seen in people without coeliac disease.
Or it could even be carbohydrates – specifically a group of short-chain carbs called “FODMAPs” that are difficult to digest and poorly absorbed in the gut. These kinds of carbohydrates occur in lots of different types of food, so going gluten-free won’t necessarily help if they are the problem.
5. “FODMAPs” are carbs that are rapidly fermented in the gut.
It’s an acronym that stands for “Fermentable Oligo-, Di-, Mono-saccharides and Polyols.” FODMAPs are found in many different foods, including some grains, fruits and vegetables, and you shouldn’t try to cut them out without first consulting with your doctor or dietitian.
6. Gibson’s new study tested 37 self-identified gluten-sensitive people.
Participants each spent a week on three different diets: high-gluten, low-gluten, and gluten-free (they didn’t know which they were on at any one time, and neither did the scientists in charge of the experiment). 95% of the food the participants ate was provided by the scientists, and the rest was “carefully controlled”, says Gibson.
In the run up to the experiment, patients were on a low FODMAP diet, and continued on that throughout.
While they were on the high-gluten diet, participants experienced the pain and other symptoms they blamed gluten for. But, curiously, they also experienced symptoms on the low-gluten and the gluten-free diet, too.
7. The results were pretty intriguing. Gibson said:
In contrast to our first study, we could find absolutely no specific response to gluten […] We found that yes, the gluten did induce symptoms, but it was exactly the same as the symptoms when they didn’t have the gluten.
8. Lee Martin, a Research Dietitian at King’s College London, told BuzzFeed:
At present there is no strong evidence to recommend a gluten free diet to treat IBS [irritable bowel syndrome] symptoms. However a low FODMAP diet has evidence for providing symptomatic relief for IBS.
Nutritional research is difficult, because restricting one food type often cuts intake of another. If symptoms improve, you don’t know what caused the problem in the first place.
In this case, says Martin, reducing gluten could improve patient’s symptoms because it’s also reducing another component of the foot i.e. FODMAPs. Or it could be that gluten does not trigger symptoms when you also reduce FODMAPs.