I’m a gastroenterologist. Here’s the surprising truth about gluten – Trisha Pasricha

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Many people believe they’re gluten-sensitive, but the real culprit could be fermentable carbs known as FODMAPs. Photo / 123rf
THREE KEY FACTS
Trisha Pasricha is a physician and journalist who writes the Ask a Doctor column for the Washington Post. She is an instructor of medicine at Harvard Medical School.
OPINION

I have lots
of patients in my gastroenterology clinic who report a sensitivity to gluten, a component of wheat, but test negative for coeliac disease. In coeliac disease, a common autoimmune condition that is rising worldwide, gluten triggers inflammation in the small bowel. But many people without coeliac disease perceive a variety of symptoms they connect to eating gluten: bloating, diarrhoea, and even brain fog, fatigue or joint aches.

While some patients do truly have a gluten-specific sensitivity, there’s a good chance it’s not actually the gluten that’s the issue. In an Italian study of nearly 400 patients complaining of symptoms related to gluten intake, the vast majority – 86% – did not experience any symptom improvement with a gluten-free diet.
Instead, I often advise a trial of a low FODMAP diet, particularly for those with irritable bowel syndrome. FODMAPs are a group of fermentable carbohydrates found in wheat and many other foods that are notorious for gastrointestinal distress. Examples of FODMAPs include:
A randomised placebo-controlled crossover study published in Gastroenterology in 2013 found that among patients who believed they had a gluten sensitivity, all patients consistently noted relief in their gut symptoms when they went on a low FODMAP diet. Later, the study found that symptoms returned regardless of whether they ate foods with gluten or adhered to a strictly gluten-free diet.
That doesn’t mean we should all make these changes to our diets. If you’re otherwise healthy, don’t skimp on whole grains such as whole wheat bread and pasta, which I would consider “good gluten”. In addition to being heart healthy, whole grains are also rich in fibre, helping you stay regular and reducing colorectal cancer risk, a big win-win in my book.
This is a common question from my patients. For most scenarios, including in inflammatory bowel disease or cognitive scores, the data is reassuring: Gluten intake doesn’t increase the risk of bad outcomes.
One group where I might consider limiting gluten intake, though, would be among people, especially children, in whom there is a strong family history of coeliac disease. There have been several studies looking at this, notably a study published in JAMA of 6605 children with a genetic predisposition to coeliac disease that found about a 7% increased risk of coeliac disease for every gram of increased gluten intake per day (the equivalent of about a half slice of white bread).
Limiting gluten intake can be very difficult from a social and economic standpoint, especially at a young age. It’s worth having a more nuanced discussion with your physician about the possible pros and cons of doing so, and the limits of the data to date.
There are a few clear scenarios where avoiding gluten has improved outcomes, including in patients who do have gluten sensitivity. We don’t always understand why gluten sensitivity occurs, but one clue comes from an important 2014 study that examined the small bowel of patients reporting food sensitivities.
Using a powerful microscope, scientists were able to observe that exposure to wheat induced inflammation in the gut that would not normally be detected outside a research setting. This reaction is different from a traditional wheat allergy, which is more common in children and often resolves by adulthood.
In the study, avoidance of the food trigger was shown to significantly help patients’ symptoms with these findings. These patients would have otherwise been classified as having irritable bowel syndrome.
You may have seen on TikTok that people report they can’t tolerate gluten in the United States but are able to eat pasta and bread in Europe.
It’s often very hard to pin down the role of gluten specifically. When people’s symptoms do get better after going gluten-free, it could also be that they’re making other beneficial changes to their diet like eating more fruits and veggies, which could account for the improvement.
In addition to other lifestyle changes, the ways we process crops and foods in the United States can be very different from other countries, and it could be that other triggers in what we eat and how we live our daily lives are driving the response beyond gluten itself.
People often think adopting a gluten-free diet is healthier in part because foods containing gluten, such as white bread and cakes, can have a high glycemic index. But many packaged “gluten-free” foods are ultra-processed. So while you may be removing gluten, you could be replacing it with other unwanted modifications of ultra-processing, including additives and sodium, and end up consuming foods that aren’t as nutrient-dense.
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