The Connection Between Celiac Disease and Diabetes

Roughly 10 percent to 20 percent of people with diabetes develop celiac disease

Woman testing for diabetes
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Being diagnosed with both celiac disease and diabetes—especially type 1 diabetes (also known as juvenile diabetes)—is very common. The estimated rate of celiac disease in people with juvenile diabetes ranges from 10 percent to 20 percent (meaning that for every 100 people with type 1 diabetes, somewhere between 10 and 20 will also have celiac disease). By comparison, the rate of celiac disease in the general U.S. population is about 1 percent.

Why the Combo Is Common

Figuring out why celiac disease and diabetes so often occur together is the focus of a lot of research. Scientists are likely to discover more about the connection in the future, but here's what's known at the moment. 

Celiac disease and type 1 diabetes are both autoimmune diseases. This means that they both involve tissue damage from autoimmune attacks. In celiac disease, the body's immune system attacks the small intestine, whereas, in diabetes, the body attacks the pancreas. Also, both diseases involve food intolerances that require special diets: no gluten for people with celiac disease, and little or no sugar for people with diabetes.

Also, it turns out that the two diseases share some genes. In fact, researchers believe that celiac disease and diabetes probably have at least seven genes in common, and there may be more.

Getting Tested for Both

Since the genetic links between the diseases are becoming clearer, many doctors now recommend that anyone who's been diagnosed with type 1 diabetes should also get tested for celiac disease.

(Some experts also advise that patients who have type 1 diabetes or celiac disease—or both—should be tested for autoimmune thyroid disease.)

It's important to remember that just being tested once for celiac disease is not enough because the disease can develop later in life. Therefore, people with diabetes need to be periodically retested for celiac disease, especially if they experience any growth failure, failure to gain weight, weight loss, or gastrointestinal symptoms.

According to the Kovler Diabetes Center at the University of Chicago, people are usually diagnosed with diabetes before they're diagnosed with celiac disease. That's mostly because doctors and the public are more familiar with diabetes.

How to Know Whether You Have Celiac Disease

If you have diabetes and you're wondering whether you might have celiac disease, study up on the common symptoms. In addition to those symptoms, there are certain features of undiagnosed celiac disease that are specific to people with diabetes, including unpredictable or unexplainable swings in blood sugar levels; hypoglycemia a couple hours after a meal or hypoglycemia that is hard to treat; and reduced insulin needs.

All of these are a result of malabsorption that's related to celiac disease. In the simplest terms: Due to the damage to your small intestine, the food that you're eating is not being absorbed properly into your body.

Why Celiac Disease Should Be Treated

Studies have shown that once people who have both diabetes and celiac disease are on a ​gluten-free diet, the episodes of hypoglycemia are reduced, but it takes several months of being on the diet for the effect to be obvious. However, these folks will face other challenges.

So there are pros and cons to staying on a gluten-free diet when you have both diabetes and celiac disease, but since celiac disease is associated with serious complications, the advantages of staying gluten-free far outweigh the disadvantages.

For example, one large study from Denmark showed that patients with type 1 diabetes and untreated celiac disease had, on average, significantly lower height and weight compared to diabetic patients without celiac disease, and they were significantly younger when they developed diabetes. Two years after the celiac patients started on gluten-free diets, they had gained weight, and those who were younger than 14 years old had also caught up in height.

Everyone also had more iron (hemoglobin and ferritin) in their blood. This type of research highlights the importance of being tested for celiac disease and following a gluten-free diet if you are diagnosed with the condition. 

Sources:

Simell S, Hoppu S, Simell T, et al. Age at Development of Type 1 Diabetes and Celiac Disease-Associated Antibodies and Clinical Disease in Genetically Susceptible Children Observed from Birth. Diabetes Care. 2010 Jan 7. [Epub ahead of print]

Sun S, Puttha R, Ghezaiel S, et al. The effect of biopsy-positive silent coeliac disease and treatment with a gluten-free diet on growth and glycaemic control in children with Type 1 diabetes. Diabet Med. 2009 Dec;26(12):1250-4.

Maggie Moon, MS, RD. Double Trouble — Counseling Clients With Diabetes and Celiac Disease. Today’s Dietitian 2009;11:32.

Kupper C, Higgins LA. Combining diabetes and gluten-free dietary management guidelines. Practical Gastroenterology. 2007;31(3):68-83.

Juvenile Diabetes Research Foundation International: Double Diagnosis: Living with Type 1 Diabetes and Celiac Disease

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