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Recently a friend I’ll call Anne told me she had cut gluten out of her diet to try to reduce joint pain in her hands. “I feel so much better,” she said. Anne is just one of many people who have self-prescribed such a diet, avoiding wheat because gluten is the primary nourishment protein in the developing plant. Usually people do this after hearing—anecdotally or from social media—that gluten is inflammatory and at the root of a range of physical and mental problems.
Anne’s story gave me pause. I have been known to joke that I am on an all-gluten diet because I enjoy bread and baked goods so much. But she and I are the same age, and I, too, have joint pain in my hands. Might that improve if I gave up gluten?
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This is a question of considerable medical importance. For the roughly 1 percent of the population with celiac disease, gluten is clearly the problem. In celiac disease, white blood cells in the immune system regard gluten as a foreign invader, like a bacterium, and start attacking. The pain can be intense. “The intestinal cells get damaged, and that leads to intestinal malfunction,” says Benjamin Lebwohl, a gastroenterologist and researcher at Columbia University’s Celiac Disease Center.
Celiac, which is linked to immune system genes called HLAs, causes a range of gut-related symptoms, including stomach pain, diarrhea and constipation. The ability to absorb nutrients goes down, leading to weight loss. There can also be damage beyond the gut such as brain fog, joint pain and infertility. No wonder people struggling with the disease have become so worried about gluten.
More general concerns about gluten causing inflammation appear misguided, however. In most people without celiac disease, eating gluten does not cause digestive problems. Nor has it been found to activate inflammatory markers in the gut. The inaccurate idea that gluten is inflammatory “is largely promoted via social media, [which] often escalates misconceptions and misinformation,” says Elena Nikiphorou, a rheumatologist at King’s College Hospital in London.
Still, not everyone without celiac disease can easily digest wheat. Some have been diagnosed with nonceliac gluten sensitivity. When they stop eating gluten, they say they feel better. Why that should be is largely a mystery. “There’s very little we really understand about why gluten makes people feel ill outside of the world of celiac disease,” Lebwohl says.
In some cases, people do have celiac but haven’t been properly diagnosed. It’s important to rule the illness out, Lebwohl says. Patients should also rule out wheat allergies. There’s a new test in which researchers can use a tiny microscope in the intestines to watch as mucosal cells in the gut are challenged by possible allergens. It has revealed a subtle type of reaction—so-called type two allergies. Unlike acute allergic responses that may require immediate medical intervention, type two allergies trigger slower responses in the body, over hours rather than minutes.
But most of the latest research suggests that other components in wheat are causing the symptoms people mistakenly ascribe to gluten. The condition should be called nonceliac wheat sensitivity, not gluten sensitivity, says Detlef Schuppan, a gastroenterologist and immunologist at the University of Mainz School of Medicine in Germany.
Schuppan and others have shown repeatedly that other wheat proteins, amylase trypsin inhibitors (ATIs), cause autoimmune responses and intestinal inflammation in mice and in humans. “These were the innate immunity triggers, not the gluten itself,” Schuppan says. ATIs could be part of the problem in celiac disease, in wheat sensitivity and in some cases of irritable bowel syndrome.
Researchers have investigated the role of FODMAPs, a large group of short-chain carbohydrates, including wheat and dairy molecules that can be hard to digest. If someone has an issue with FODMAPs, cutting out wheat alone can seem like a solution. Still, one study comparing a reduced-FODMAP diet with a gluten-free diet found the latter more effective at reducing many symptoms.
As for joint pain, there may be shared underlying processes between rheumatoid arthritis (RA) and celiac disease. Some studies have found limited improvement of inflammatory joint symptoms in rheumatoid arthritis patients who stop eating gluten and some other suspect foods. But Nikiphorou emphasizes that most of the research has limitations such as a short testing duration, and experts aren’t yet convinced by the evidence of a dietary treatment for RA.
The most common source of joint pain in people older than 40 years is, in fact, not RA but osteoarthritis (OA), which develops from wear and tear on joints and not from an autoimmune response. “I would think it unlikely for gluten to impact OA,” Nikiphorou says. (ATIs could be the culprit in someone with joint pain, Schuppan suggests.)
Adopting a gluten-free diet unnecessarily can bring risks. Such diets are often low in fiber, which can increase the risk of heart disease, according to Lebwohl and his colleagues. Many gluten-free products are also lacking in nutrients and are ultraprocessed, which recent research shows to be unhealthy.
Experts emphasize that only people with true celiac disease need to avoid gluten from all sources. People with type two wheat allergies or an ATI sensitivity can improve symptoms by reducing consumption by 80 to 90 percent, Schuppan says.
That’s an approach I might consider … after I make a sandwich for lunch.
