Before gluten had a name, celiac disease had a look: a child with a swollen belly, thin limbs, and bowed legs from rickets. The disease was understood as a childhood wasting condition, one you could see across a room. Today it more often shows up as a number on a lab sheet: a ferritin stuck at 9, a vitamin D level that barely moves, a B12 that sits at the bottom of the reference range. That is the same disease with a different shadow.

I started reading the old case reports after celiac entered our family. I expected to learn about villi and gluten. I did not expect to learn how much the disease had changed its presentation, or how much vitamin status could tell us before anyone thought to look.

A Disease That Changed Its Shape

In 1888, Dr. Samuel Gee described children with chronic diarrhea and wasting who did not respond to ordinary medicine. He suspected food mattered. For the next several decades, doctors wrote about children with distended bellies, thin limbs, and bone deformities caused by calcium and vitamin D malabsorption. They used terms like celiac rickets and celiac tetany. Those old case reports spell out the nutrient loss.

The shift began during the Dutch Hunger Winter of 1944 to 1945, when wheat disappeared from the food supply. A Dutch pediatrician named Willem-Karel Dicke noticed that children with celiac improved while bread and wheat flour were scarce, then worsened when wheat returned after the war. He published his findings in 1950. That observation eventually led to the gluten-free diet we know today.

Once removing wheat became standard, the most visible cases grew less common. The child with a swollen belly and bowed legs faded from the textbooks. In the 1980s and 1990s, blood tests for celiac antibodies made screening easier. Clinicians began diagnosing adults who had no diarrhea at all but showed up with anemia, low bone density, or a ferritin that would not rise despite iron pills. Celiac did not disappear; its presentation changed.

The Nutrient Paper Trail in Celiac

Untreated celiac damages the villi in the small intestine, especially in the duodenum, the first section after the stomach. That is where iron absorption happens. Low iron, and specifically low ferritin, is one of the most common lab findings in adults at diagnosis. A complete blood count can look normal while ferritin sits at the bottom of the reference range.

The pattern varies from person to person. Some people have a single low ferritin; others have several deficiencies.

• Iron: Damage in the duodenum reduces absorption, and chronic inflammation lowers ferritin. Low iron shows up as fatigue, pale skin, or restless legs.
• Vitamin D: Fat malabsorption reduces uptake of fat-soluble vitamins. Low vitamin D shows up as bone pain, low mood, or muscle weakness.
• Calcium: Villi damage and low vitamin D interfere with absorption. Low calcium causes muscle cramps, numbness, or low bone density.
• Vitamin B12: Chronic inflammation or ileal involvement affects absorption. Low B12 presents as tingling, brain fog, or anemia.
• Folate: Upper small intestine damage limits absorption. Low folate often appears as fatigue or anemia.
• Zinc: Jejunal damage and increased losses lower levels. Low zinc changes taste, thins hair, or slows healing.

I share these because I needed to understand why the labs mattered. Any single finding on this list is a reason to talk with your clinician, not a reason to raid the supplement aisle.

The Gap in a Strict Gluten-Free Diet

Removing gluten stops the trigger, but it does not restore the intestinal lining overnight. A 2010 study in the American Journal of Gastroenterology followed 241 adults with biopsy-confirmed celiac disease after they started a gluten-free diet. Intestinal recovery, confirmed by follow-up biopsy, was present in 34 percent of participants at two years and 66 percent at five years. For many people, absorption stays low during that recovery window. If you start a gluten-free diet and wait for labs to fix themselves without a baseline, you hide a problem.

Then there is the food itself. In the United States, wheat flour has carried added iron and B vitamins since the 1940s. Folic acid was added to the enrichment standard in 1998. Many gluten-free flours and packaged foods made from rice, tapioca, and potato starch are not part of that enrichment program. A person who swaps wheat bread for a gluten-free loaf removes an enriched staple and replaces it with one that carries little added iron and B vitamins. Some gluten-free products are fortified, but many are not.

Some newly diagnosed people also avoid dairy because the damaged brush border makes lactose hard to digest. That drops a major source of calcium and vitamin D. The result is a diet that removes the trigger but leaves nutrient gaps until dairy returns.

What I Ask at Checkups

After celiac entered our family, I asked our clinician for a baseline nutrient panel: ferritin, a full iron panel, vitamin D, B12, folate, and zinc. I wanted a baseline, not a management plan. Recovery takes time, and a baseline keeps us honest. Six months later, if the ferritin has not moved or the vitamin D is still low, that prompts a conversation with our clinician.

I also learned that a lab reference range is not the same as a target for someone rebuilding after malabsorption. A ferritin at the low end of the lab's normal range is not the same as a ferritin that reflects rebuilt iron stores. I bring that question to appointments instead of guessing.

I keep supplements simple. Iron and vitamin D are harmful at high doses, so I do not self-prescribe. We recheck labs before adding anything new. Food first, targeted supplements only when a clinician recommends them.

Why Old Case Reports Still Show Up in Bloodwork

The celiac disease described in old case reports was visible. It came with a bloated belly and legs that bowed. The celiac disease many families meet today is quieter. It shows up in a blood test that has been slightly off for years, in fatigue that gets blamed on parenting, in a ferritin that will not rise despite iron pills. The body's nutrient needs have not changed. What changed is how often we look.

I am not a clinician, and this is not medical advice. It is what I have learned from published research and from living in a celiac household. If you are newly diagnosed or feeding someone who is, start with a conversation with your clinician about baseline labs. Then come cook with us. Clean Monday Meals has a free Recipe App with hundreds of gluten-free and dairy-free recipes built around real ingredients. It makes filling plates with home-cooked food feel doable, not overwhelming. Tag us @cleanmondaymeals when you make something.

With love, Janae