Research shows that about 1 in 4 adults with celiac disease also have other autoimmune diseases, most commonly thyroid problems, according to a 2026 study of 102 patients. Nearly all patients (93.1%) had at least one nutritional deficiency, with vitamin D deficiency affecting 90.2% of them, even among those who carefully followed a gluten-free diet.
A new study of 102 adults with celiac disease found that many of them also have other autoimmune conditions, where the body’s immune system attacks itself. About one in four patients had an additional autoimmune disease, most commonly thyroid problems. The research also discovered that nearly all patients were missing important vitamins and minerals, especially vitamin D. Even people who carefully followed a gluten-free diet still had these nutritional gaps. These findings suggest that people with celiac disease need regular check-ups to catch other autoimmune diseases early and monitor their nutrition levels.
Key Statistics
A 2026 prospective study of 102 adults with biopsy-confirmed celiac disease found that 25.5% had additional autoimmune diseases, with autoimmune thyroiditis being the most common at 12.7%.
According to research reviewed by Gram, 93.1% of celiac disease patients in a 2026 study had at least one micronutrient deficiency, with vitamin D deficiency present in 90.2% of the 102 participants.
A 2026 study of 102 celiac disease patients found that 15.7% had autoimmune polyglandular syndromes, with type 3 being the most frequent subtype at 11.8%.
Research from 2026 showed that 54.9% of 102 celiac disease patients had two or more micronutrient deficiencies, and those with poor gluten-free diet adherence had significantly higher rates of nutritional problems.
The Quick Take
- What they studied: Whether adults with celiac disease also develop other autoimmune diseases and nutritional deficiencies, and how well they stick to a gluten-free diet.
- Who participated: 102 adults who had been diagnosed with celiac disease through a biopsy (a tissue sample) and were being regularly monitored by doctors.
- Key finding: About 1 in 4 patients (25.5%) had additional autoimmune diseases, with thyroid problems being most common. Nearly all patients (93.1%) were missing at least one important nutrient, with vitamin D deficiency affecting 9 out of 10 patients.
- What it means for you: If you have celiac disease, you should get regular blood tests to check for thyroid problems and other autoimmune conditions, and your doctor should monitor your vitamin and mineral levels even if you follow a gluten-free diet carefully.
The Research Details
Researchers followed 102 adults who already had celiac disease confirmed by a biopsy. They collected information about each patient’s medical history, checked for other autoimmune diseases, ran blood tests to measure vitamins and minerals, and asked patients how well they followed a gluten-free diet using a specific questionnaire. This type of study, called a prospective observational study, means researchers watched patients over time and recorded what happened without changing their treatment.
The researchers looked for specific autoimmune diseases that commonly occur together with celiac disease. They also checked for a condition called autoimmune polyglandular syndromes, which means multiple glands in the body are attacked by the immune system at the same time. They measured levels of vitamin D, folate, iron, and vitamin B12 in the blood to identify deficiencies.
The study was designed to give doctors a clear picture of how common these additional problems are in people with celiac disease and whether following a gluten-free diet prevents nutritional deficiencies.
Understanding how often other autoimmune diseases occur with celiac disease helps doctors know what to screen for and monitor. Knowing that nutritional deficiencies are extremely common, even in people who follow a gluten-free diet well, shows that doctors need to actively check nutrient levels rather than assuming patients are getting enough vitamins and minerals.
This study used a clearly defined group of patients with confirmed celiac disease, which makes the results reliable. The researchers used standard medical tests and a validated questionnaire to measure diet adherence. However, the study included only 102 patients from one location, so results may not apply equally to all populations. The study was observational, meaning it shows what happens but cannot prove that celiac disease directly causes the other autoimmune diseases.
What the Results Show
Among the 102 adults with celiac disease, 26 patients (25.5%) had at least one additional autoimmune disease. Autoimmune thyroiditis, a condition where the immune system attacks the thyroid gland, was the most common, occurring in 12.7% of patients. Autoimmune polyglandular syndromes, where multiple glands are affected, were found in 16 patients (15.7%). The most common type was APS type 3 (11.8%), which typically involves the thyroid and other organs.
Nutritional deficiencies were extremely widespread. At least one micronutrient deficiency was present in 93.1% of patients, and more than half (54.9%) had two or more deficiencies. Vitamin D deficiency was by far the most common problem, affecting 90.2% of patients. This was followed by folate deficiency in 33.3% of patients, iron deficiency in 29.4%, and vitamin B12 deficiency in 17.6%.
Patients who did not follow a gluten-free diet carefully had significantly worse nutritional status than those who adhered well to the diet. Those with poor diet adherence had higher rates of multiple nutrient deficiencies, folate deficiency, iron deficiency, vitamin B12 deficiency, and iron deficiency anemia. However, even patients with good diet adherence still had high rates of nutritional deficiencies.
Iron deficiency anemia, a condition where the body lacks enough iron to make healthy red blood cells, occurred in 17.6% of patients. APS type 4, a less common form of autoimmune polyglandular syndrome, was identified in 2% of patients. APS types 1 and 2 were each found in only 1% of patients. The study found that poor adherence to a gluten-free diet was associated with worse nutritional outcomes across multiple nutrients.
According to Gram Research analysis, these findings align with previous studies showing that celiac disease frequently occurs alongside other autoimmune conditions. The high prevalence of vitamin D deficiency matches what other research has documented in celiac disease populations. The finding that nutritional deficiencies persist even with good diet adherence suggests that celiac disease may cause ongoing absorption problems that require active medical management.
The study included only 102 patients from one location, so results may not represent all people with celiac disease worldwide. The study was observational, meaning it shows associations but cannot prove that celiac disease causes the other autoimmune diseases. The researchers relied on patients’ self-reported diet adherence, which may not be completely accurate. The study did not include a comparison group of people without celiac disease, so we cannot determine if these autoimmune diseases and deficiencies occur more often in celiac disease than in the general population.
The Bottom Line
Adults with celiac disease should have regular blood tests to screen for autoimmune thyroid disease and other autoimmune conditions. Vitamin and mineral levels should be checked regularly, particularly vitamin D, folate, iron, and vitamin B12, regardless of how well patients follow a gluten-free diet. Patients should discuss supplementation with their doctor based on their individual test results. These recommendations are supported by strong evidence from this study.
Anyone with celiac disease should pay attention to these findings, especially those who have been diagnosed for several years. People with a family history of autoimmune diseases should be particularly vigilant. Healthcare providers caring for celiac disease patients should use these findings to guide their screening and monitoring practices. This research is less relevant to people without celiac disease.
Autoimmune diseases can develop gradually over months or years, so regular screening is important even if you feel fine. Nutritional deficiencies may not cause noticeable symptoms for weeks or months, which is why blood tests are necessary. If you start taking supplements, it may take several weeks to months to see improvements in energy levels or other symptoms.
Frequently Asked Questions
Do people with celiac disease get other autoimmune diseases?
Yes, about 1 in 4 people with celiac disease develop additional autoimmune diseases. A 2026 study of 102 patients found that 25.5% had other autoimmune conditions, with thyroid disease being most common at 12.7%.
What vitamin deficiencies are common in celiac disease?
Vitamin D deficiency is extremely common, affecting 90.2% of celiac disease patients in a recent study. Folate, iron, and vitamin B12 deficiencies also occur frequently, affecting 33.3%, 29.4%, and 17.6% of patients respectively.
Does following a gluten-free diet prevent nutritional deficiencies in celiac disease?
Following a gluten-free diet helps reduce nutritional deficiencies, but does not eliminate them. A 2026 study found that even patients with good diet adherence still had high rates of vitamin and mineral deficiencies, suggesting ongoing monitoring is necessary.
How often should someone with celiac disease get blood tests?
The research suggests regular monitoring is needed, though the study did not specify exact intervals. Most doctors recommend checking vitamin D, folate, iron, and B12 levels at least annually, and more frequently if deficiencies are found.
What is autoimmune polyglandular syndrome?
Autoimmune polyglandular syndrome is a condition where the immune system attacks multiple glands in the body at the same time. A 2026 study found this occurred in 15.7% of celiac disease patients, with type 3 being most common.
Want to Apply This Research?
- Log your gluten-free diet adherence daily using a simple yes/no checklist, and track when you have blood tests scheduled for vitamin D, folate, iron, and B12 levels. Set reminders for quarterly or semi-annual lab work.
- Use the app to set reminders for taking vitamin supplements as prescribed by your doctor, particularly vitamin D. Track any symptoms like fatigue or weakness that might indicate nutritional deficiencies, and log these observations to share with your healthcare provider.
- Create a long-term tracking dashboard that shows your lab results over time for key nutrients. Set annual reminders to discuss autoimmune disease screening with your doctor, and maintain a log of any new symptoms that might indicate additional autoimmune conditions.
This research describes patterns observed in a study of 102 patients and should not be used for self-diagnosis. If you have celiac disease or suspect you might, consult with a healthcare provider for proper testing and diagnosis. Do not start, stop, or change any medications or supplements without discussing with your doctor first. This article summarizes research findings and is not a substitute for professional medical advice.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.