Gluten was an issue 50 years ago, but most people suffering from it had no idea what was wrong. Celiac disease went undiagnosed for years or even decades, often mistaken for irritable bowel syndrome or other vague digestive complaints. What has changed since the 1970s is partly awareness and testing, but the story does not end there. The actual rate of celiac disease and gluten-related disorders has genuinely climbed, and researchers are still working out why.
The Problem Was Always There, but the Numbers Have Also Grown
One of the most common explanations you will hear is that we simply got better at diagnosing celiac disease. That is true, but it is not the whole truth. A Finnish study compared blood samples from over 8,000 adults collected in the late 1970s with samples from a similar group taken in 2000 and 2001. Only two people in the earlier group had been clinically diagnosed with celiac disease, compared to 32 in the later group. But crucially, when researchers tested both groups for the same antibodies, previously unrecognized cases also rose significantly, from about 1% to roughly 1.5%. The total prevalence, including undiagnosed cases, nearly doubled from about 1% to 2%.1PubMed. Increasing prevalence of coeliac disease over time
A separate U.S. study told a similar story using archived blood samples dating back to 1974. Over a 15-year follow-up window, celiac disease prevalence doubled in one cohort, and the overall U.S. prevalence appeared to have increased roughly fivefold since 1974. The researchers noted that the increase was driven by adults who lost their immune tolerance to gluten later in life, not by more people being born with the condition.2PubMed. Natural history of celiac disease autoimmunity in a USA cohort followed since 1974
This is an important distinction. If the rise were only about better diagnosis, the rate of antibodies in old stored blood samples would be the same as in new ones. It is not. Something in the environment, in our bodies, or in how we live has shifted the odds.
Modern Wheat Is Not More Toxic Than Old Wheat
A popular narrative blames modern wheat breeding for the surge in gluten problems. The idea goes something like this: agricultural scientists bred wheat for higher yield and better baking properties, and in doing so accidentally created a more immunologically aggressive grain. It is a tidy story, and it is mostly wrong.
Researchers in Germany compared old heritage wheat cultivars with modern commercial varieties, specifically measuring the peptides most responsible for triggering the immune response in celiac disease. The key immune-reactive fragments showed no clear trend of increasing over time. Some old varieties were actually higher in these peptides than some modern ones. The study concluded that the immunoreactive potential of old and modern wheat cultivars appears to be similar.3Food Chemistry. Old and modern wheat (Triticum aestivum L.) cultivars and their potential to elicit celiac disease
This does not mean wheat is identical to what your grandparents ate. The total amount of wheat in the Western diet has changed, and the way it is processed before it reaches your plate has changed dramatically. But swapping back to an heirloom grain is unlikely to solve a gluten problem on its own.
How Bread-Making Changed
If the wheat itself has not become more dangerous, the way we turn it into food deserves a closer look. Traditional bread-making relied on long fermentation with sourdough cultures, a process that can take 12 to 24 hours or more. During that slow rise, bacteria and wild yeasts produce enzymes that partially break down gluten proteins. Research has shown that sourdough fermentation, especially when combined with certain grain-derived enzymes, can extensively degrade wheat proteins, to the point where some researchers have explored it as a way to develop products tolerable for people with gluten intolerance.4Trends in Food Science & Technology. Proteolysis in sourdough fermentations: mechanisms and potential for improved bread quality
Modern commercial bread-making is a different animal. Industrial bakeries use fast-acting yeast and short rise times, sometimes under two hours from mixing to baking. The gluten in that bread arrives in your gut largely intact. Add to this the fact that gluten itself is now used as an additive in products well beyond bread. It shows up in sauces, processed meats, soups, snack foods, and even some medications. A U.S. analysis of pharmaceutical products found that gluten-derived proteins were detectable in the majority of both prescription and over-the-counter medicines tested.5PubMed Central. Gluten in pharmaceutical products: a scoping review The total daily gluten load for the average person has grown not because each slice of bread is worse, but because gluten is everywhere in a modern processed diet.
It Might Not Even Be the Gluten
Here is where the picture gets genuinely interesting. A significant number of people who feel better on a gluten-free diet do not have celiac disease, and growing evidence suggests that for many of them, gluten may not be the actual trigger.
Wheat contains a family of proteins called amylase-trypsin inhibitors, or ATIs. These molecules evolved as a natural pest defense for the wheat plant. In the human gut, they activate a specific receptor on immune cells, kicking off an inflammatory response. This happens in both celiac and non-celiac individuals.6PubMed Central. Wheat amylase trypsin inhibitors drive intestinal inflammation via activation of toll-like receptor 4 Follow-up work confirmed that these wheat ATIs stimulate immune cells in a dose-dependent way, producing an inflammatory response comparable to bacterial toxins.7Gastroenterology. Nutritional Wheat Amylase-Trypsin Inhibitors Promote Intestinal Inflammation via Activation of Myeloid Cells When you remove wheat from your diet, you remove ATIs along with gluten. So someone who feels better “going gluten-free” may actually be responding to the absence of ATIs, not gluten itself.
Then there are fructans, a type of short-chain carbohydrate classified as a FODMAP. Wheat is one of the most common dietary sources of fructans in Western diets. A randomized, double-blind, placebo-controlled trial gave people with self-reported non-celiac gluten sensitivity either isolated gluten, fructan, or a placebo and measured their symptoms. Fructans triggered significantly more symptoms than gluten did.8PubMed. Fructan, Rather Than Gluten, Induces Symptoms in Patients With Self-Reported Non-Celiac Gluten Sensitivity For many people who feel bloated and miserable after eating pasta or bread, the culprit is likely the fructan in the wheat, not the gluten protein.
This matters because the question “why wasn’t gluten an issue?” may be slightly misframed. Wheat-related discomfort is the issue, and gluten is only one of several components of wheat that can cause trouble. The popular focus on gluten has oversimplified a messier reality.
Your Gut Is Different From Your Grandparents’ Gut
Even if the grain has not changed much, the human side of the equation has. The community of microbes living in the human intestine, and the immune system that developed alongside those microbes, looks meaningfully different today than it did a few generations ago.
A systematic review and meta-analysis found that early-life infections and antibiotic exposure both appear to increase the odds of developing celiac disease. The authors pointed to disruption of the gut microbial community as a plausible link between these exposures and later immune problems.9PubMed. Infection, antibiotic exposure, and risk of celiac disease: A systematic review and meta-analysis Antibiotic use in children has risen steeply since the mid-twentieth century, and each course can reshape the gut microbiome in ways that persist for months or years.
Ultra-processed foods, which now make up more than half of caloric intake in many Western countries, add another layer. These foods tend to be low in fiber and high in synthetic emulsifiers and additives, and they are associated with reduced microbial diversity, lower levels of beneficial bacteria, and an increase in pro-inflammatory organisms. The resulting low-grade inflammation is linked to a range of chronic gut disorders.10PubMed Central. The Detrimental Impact of Ultra-Processed Foods on the Human Gut Microbiome and Gut Barrier
The broader framework here is sometimes called the hygiene hypothesis, though its scope has expanded well beyond hygiene. The idea is that the declining burden of childhood infections in Western countries, along with cleaner water, smaller families, and less contact with farm animals and soil microbes, has left the immune system under-trained and prone to overreacting to harmless proteins like gluten. This hypothesis was originally proposed to explain the rise of allergies, but it has since been extended to autoimmune conditions including celiac disease.11Clinical and Experimental Immunology. The ‘hygiene hypothesis’ for autoimmune and allergic diseases: an update
What Happens When Gluten Meets the Gut Wall
Understanding why gut health matters here requires a quick look at what gluten actually does once it arrives in the intestine. Gliadin, the fraction of gluten that causes the most trouble, triggers the release of a protein called zonulin from intestinal cells. Zonulin loosens the tight junctions between cells lining the gut, temporarily increasing permeability. In lab studies, gliadin exposure led to zonulin release, rearrangement of the cell structure, and a measurable loss of barrier integrity.12PubMed. Gliadin, zonulin and gut permeability: Effects on celiac and non-celiac intestinal mucosa and intestinal cell lines
Further research showed that gliadin triggers this process by binding to a specific receptor on gut cells. When that receptor was knocked out in mice, gliadin no longer caused increased permeability or zonulin release.13Gastroenterology. Gliadin Induces an Increase in Intestinal Permeability and Zonulin Release by Binding to the Chemokine Receptor CXCR3 This is relevant to the historical question because a gut that is already inflamed or has a disrupted microbial community may respond more dramatically to this gliadin-driven permeability increase. In other words, the same slice of bread might provoke a stronger reaction in a gut that has been shaped by modern antibiotics, processed food, and reduced microbial exposure than it would in a gut from 1970.
Geographic Clues
If the explanation were purely genetic, you would expect celiac disease to appear at similar rates across populations with similar ancestry. It does not. A large European screening study found striking variation even within the continent: celiac disease affected about 2.4% of Finnish adults aged 30 to 64, compared to about 0.7% in Italy and only about 0.3% in Germany.14PubMed. The prevalence of celiac disease in Europe: results of a centralized, international mass screening project These populations share broadly similar genetic backgrounds and eat wheat-based diets, yet their rates differ by almost an order of magnitude.
That gap points toward environmental factors specific to each region: the types of wheat used in local cuisine, how bread is traditionally prepared, infant feeding customs, patterns of antibiotic prescribing, and the overall diversity of the local diet. Finland’s high rate, for instance, coexists with high levels of other autoimmune conditions, suggesting that something about the Northern European environment or lifestyle primes the immune system in a particular way. These geographic patterns reinforce the idea that celiac disease is not simply a genetic inevitability triggered by wheat, but a condition shaped by the full context in which wheat is consumed.
The Glyphosate Question
If you search for reasons behind the rise in gluten intolerance, you will quickly encounter claims about glyphosate, the active ingredient in the herbicide Roundup. The argument is that glyphosate residues on wheat, which have increased as farmers adopted the practice of spraying crops shortly before harvest, are damaging the gut and driving celiac disease rates upward. This idea gained traction partly from a 2013 paper that proposed glyphosate as “the most important causal factor” in the celiac epidemic.15PubMed Central. Glyphosate, pathways to modern diseases II: Celiac sprue and gluten intolerance
That paper, however, is a hypothesis piece, not an experimental study. It relies on correlations between glyphosate use trends and disease trends, a type of evidence that is notoriously unreliable for establishing cause and effect. The authors did not measure glyphosate exposure in celiac patients or show a biological mechanism through controlled experiments. The broader scientific community has been skeptical, and regulatory agencies in the U.S. and Europe have not identified a link between typical dietary glyphosate exposure and celiac disease. The idea persists in popular culture, but it should be treated as an unproven hypothesis rather than an established explanation.
The Cultural Feedback Loop
A separate force has amplified the visibility of gluten problems far beyond the clinical population. By 2013, roughly 30% of American adults reported that they were trying to reduce or eliminate gluten from their diets. Retail sales of gluten-free products had grown by about 28% over the preceding decade, reaching a multi-billion-dollar market.16Gastroenterology. “But we’re not hypochondriacs”: The changing shape of gluten-free dieting and the contested illness experience Most of those people did not have celiac disease.
This created a feedback loop. As more people went gluten-free and reported feeling better, the cultural perception that gluten is broadly harmful spread. Food companies responded with products and marketing, which further normalized the idea. Restaurants added gluten-free menus. Celebrities endorsed the diet. The net effect was that “gluten” became shorthand for a wide range of wheat-related and even non-wheat-related digestive discomfort, making it appear as though a single protein had suddenly become toxic to millions of people.
Some of those people genuinely feel better because they have undiagnosed celiac disease. Some feel better because removing wheat also removes fructans or ATIs. Some feel better because going gluten-free often means eating fewer processed foods overall. And some feel better because of the placebo effect and the psychological reassurance of having identified a cause for vague symptoms. All of these are real phenomena, and they all get lumped together under the label “gluten sensitivity,” which muddies the science and frustrates researchers trying to draw clean lines.
Why Late Diagnosis Used to Be Dangerous
One underappreciated part of the historical picture is just how much damage undiagnosed celiac disease caused before awareness improved. Without routine screening, people with celiac disease often went years or decades eating gluten, accumulating intestinal damage that sometimes led to severe complications. Case reports describe patients managed for years under incorrect diagnoses before celiac disease was finally identified, sometimes only after life-threatening complications like intestinal lymphoma had developed.17PubMed Central. Celiac disease and fulminant T lymphoma detected too late in a 35-year-old female patient: case report
Fifty years ago, these patients existed. They had chronic diarrhea, unexplained anemia, osteoporosis at a young age, infertility, or vague neurological symptoms. Many were told they had a “nervous stomach” or were simply anxious. The disease was considered rare because doctors were not looking for it and the blood tests to screen for it did not yet exist. The shift from “rare disease” to “common condition” happened partly because we started counting properly, and partly because the actual numbers climbed. Both are true at the same time.
Early Life and the Window of Tolerance
When and how infants are first exposed to gluten may influence whether they develop celiac disease later. Research has explored whether introducing small amounts of gluten during a specific window in infancy, around four to six months, might help train the immune system to tolerate it. A UK study found potential benefits to introducing gluten at four months of age.18PubMed Central. Can early introduction of gluten reduce risk of celiac disease? Infant feeding practices have changed considerably over the past half-century. Breastfeeding rates, the timing of solid food introduction, and the types of first foods given to babies have all shifted, sometimes in response to medical advice that was later revised. Whether these changes have contributed to rising celiac rates is still being studied, but the broader point holds: the conditions under which a child’s immune system first encounters gluten have changed alongside everything else.
None of this means parents should panic about when they introduce toast or cereal. The evidence is not yet strong enough to issue precise recommendations beyond existing pediatric guidelines. But it illustrates how the answer to “why wasn’t gluten an issue?” reaches into parts of modern life that seem far removed from a loaf of bread.