My celiac diagnosis in 2014 didn't match the symptom lists in older medical textbooks. Those lists described a child with chronic diarrhea, a swollen belly, and failure to thrive. None of that described me. The descriptions came from a narrow slice of the disease that doctors built around severe childhood cases first documented in the late 1800s. Adult patients were left out of that picture for a long time.

A disease that seemed to belong to children

In 1888, a British physician named Samuel Gee published a description of celiac disease that focused on children with wasting and diarrhea. For the next several decades, doctors treated the condition almost entirely in pediatric wards. Adults with the same intestinal damage usually received a different diagnosis because the textbooks didn't include them. Treatment was dietary experimentation. In the 1920s, a New York pediatrician named Sidney Haas promoted a banana-based diet for children with the disease. It helped some patients, but nobody had identified the real trigger.

Danish physician Ejnar Thaysen changed that picture in 1932. He published a series of adult cases that showed the same intestinal damage appearing in people in their 30s and older. Some had digestive symptoms, and some didn't. The disease didn't have to begin in childhood. It could appear later in life. Thaysen's work forced the field to expand what it considered possible.

Blood tests in the 1990s changed the numbers

In the 1990s, researchers developed tests for antibodies that show up when someone with untreated celiac eats gluten. Those tests made it possible to screen large groups of people instead of waiting for a person to arrive with severe symptoms.

A 1994 study led by pediatric gastroenterologist Carlo Catassi screened more than 17,000 Italian schoolchildren and found celiac in about 1 in 184. A 2003 study led by gastroenterologist Alessio Fasano tested blood samples from U.S. donors and found a rate of about 1 in 133. Both pointed to the same conclusion. Most people with celiac didn't know they had it.

Symptoms that show up outside the gut

The old textbook description assumed the disease announced itself with diarrhea. That assumption caused decades of missed adult diagnoses. For many adults, the first noticeable problems appear somewhere other than the digestive tract.

• Iron-deficiency anemia that doesn't improve with iron supplements
• Unexplained osteoporosis before age 50
• A chronic itchy blistering rash called dermatitis herpetiformis
• Migraine frequency that increases in some people
• Celiac alongside type 1 diabetes or autoimmune thyroid disease often enough that doctors screen for it even without digestive symptoms

Some adults have what researchers call silent celiac. Their blood tests are positive and their small intestine is damaged, but they notice no symptoms at all. Those cases often surface by accident, for example when a doctor orders testing because a close relative has the disease or because routine lab work shows unexplained anemia. Studies report an average delay of six to ten years between first symptoms and diagnosis in adults. Much of that delay traces back to the old idea that you must have diarrhea to be considered.

Frozen blood from the 1950s

A 2009 study led by gastroenterologist Joseph Murray compared frozen blood samples from Air Force recruits collected in the 1950s with samples from people collected in the 1990s and early 2000s. The rate of celiac antibodies was about four times higher in the later group.

The 1950s samples also contained celiac antibodies, which meant the disease existed back then. The change was in how common it became and how often doctors looked for it. More people had it, and more people were being identified.

What I tell friends now

When a friend in her 30s or 40s tells me she has been exhausted for months, or that her iron levels keep coming back low, or that she gets frequent migraines, I don't jump to conclusions. I suggest she ask her doctor to consider celiac in the mix.

I'm not a clinician, so I don't give medical advice. If something feels off, talk to your physician or a registered dietitian. The first step is a blood test for tissue transglutaminase antibodies. If that is positive, an intestinal biopsy can confirm the diagnosis. You need to be eating gluten when you have those tests, because removing gluten first can make the results unreliable.

What my celiac diagnosis taught me about food

When my daughter was diagnosed with celiac after her type 1 diabetes diagnosis, I saw the same confusion I had felt. She wanted ramen, and I couldn't find a gluten-free version with ingredients I trusted. That frustration led to Clean Monday Meals. Every product we make is gluten-free, dairy-free, and soy-free.

If you're learning to live with celiac, you don't have to figure out meals alone. Our free Recipe App has hundreds of gluten-free, dairy-free recipes, meal plans, and shopping lists. I hope it saves you the years of guessing that came before.