Gluten has become the dietary villain of our time, sending thousands of health-conscious adults scurrying down the supermarket gluten-free aisle. But is gluten really the problem it’s made out to be or are we being taken on a wild wheat-free ride?
Gluten has been blamed for a whole raft of health issues, from the well-researched autoimmune response in coeliac disease to the more elusive gluten sensitivity, which is the subject of ongoing research.
While coeliac disease affects about 1% of New Zealanders, a further 6-10% of people believe they are gluten-sensitive, despite not having coeliac disease or a diagnosed wheat allergy.
Coeliac disease (CD) is an incurable autoimmune disorder triggered by gluten, a protein in wheat, barley rye, and oats. When people with CD consume gluten, they produce antibodies that damage the small intestine, impairing nutrient absorption and leading to symptoms such as diarrhoea, fatigue, weight loss, anaemia and abdominal pain. Fortunately, CD can be diagnosed with blood tests and a biopsy, then treated with a lifelong gluten-free diet.
While coeliac disease has a precise diagnosis and treatment, non-coeliac gluten sensitivity has neither. Despite this, many people attribute symptoms such as fatigue, bloating, abdominal pain and migraines to gluten and adopt a gluten-free diet, often believing it’s healthier – something that’s not necessarily true.
Researchers have now coined the term non-coeliac gluten sensitivity for these symptoms. Still, it remains a poorly defined syndrome with no reliable diagnostic tests and ongoing debate about its existence and causes.
Recently, researchers from Maastricht and Leeds universities studied more than 80 people with self-reported non-coeliac gluten sensitivity, excluding those with coeliac disease or wheat allergies.
Participants were randomly given gluten-free or gluten-containing meals without knowing the actual content. Published in The Lancet Gastroenterology and Hepatology in 2023, the results showed that people who believed they were consuming gluten reported more symptoms, regardless of the true gluten content. Hence, people’s expectations played a prominent role in whether they reported symptoms after eating.
Explains researcher Marligne de Graaf, “We see a so-called nocebo effect when people eat gluten. If people expect gluten to produce negative effects, they experience symptoms, even if it turns out afterwards that they weren’t actually eating gluten. Although the cause is partly ‘in the mind’, this doesn’t mean that the symptoms are not real.”
Indeed, a well-recognised link exists between the gut and brain, which scientists will investigate further to unravel potential mechanisms linking psychological factors such as expectations and physical exposure to gluten. Certainly, patients with self-reported non-coeliac gluten sensitivity have some intriguing common features, such as a higher rate of anaemia (34.8%) than patients with irritable bowel syndrome (17.4%) and higher rates of autoimmune diseases and autoantibodies than their peers. Why, then, are autoimmune conditions more common among people with self-described NCGS?
Added to that, researchers are unsure if non-coeliac gluten sensitivity is even an appropriate name for this syndrome, given other wheat components are known to cause similar symptoms. For instance, the fructans found in wheat, along with other fermentable oligosaccharides, disaccharides, monosaccharides and polyols (known as FODMAPs), can cause gastrointestinal symptoms in people with irritable bowel syndrome, and those symptoms are almost indistinguishable from the symptoms of non-coeliac gluten sensitivity.
People reporting gluten sensitivity may have irritable bowel syndrome and react to fructans in wheat rather than gluten. Thus, researchers have suggested a better term for this constellation of health problems could be non-coeliac wheat sensitivity rather than non-coeliac gluten sensitivity.
So, while gluten is often blamed for a range of health issues, the true picture is more nuanced. Coeliac disease is a well-established condition, but non-coeliac gluten (or wheat) sensitivity remains vague and poorly defined.
All in all, consumers should approach the concept of gluten sensitivity carefully and remain open to the possibility that the solution to their symptoms may lie somewhere other than the gluten-free supermarket aisle.
