By Lindsey Bewley McCann

Counting carbohydrates is second nature to most people who live with type 1 diabetes (T1D). Gauging grams of carbohydrates and translating the information into insulin calculations needed to cover them—it all becomes pretty routine. But what about the approximately 10 percent of people with T1D who also suffer from celiac disease? In this case, “double-diet duty” is needed, because carbohydrate choices and computations become more complicated. Managing T1D and celiac disease calls for redesigning carb strategies. But first, here’s what it is all about.

What is celiac disease?

In celiac disease, a person’s body is not able to digest foods that contain gluten, which is a protein found in wheat, rye, barley, and some other grains. If a person with this disease eats a piece of wheat bread, for example, his or her immune system reacts to the offending gluten by damaging the lining of the small intestine (part of the gastrointestinal tract). Because most nutrients in food are absorbed in the small intestine, the damage caused by celiac disease can result in poor absorption of essential nutrients and a decrease in the body’s ability to utilize them. Over time, this damage can cause nutritional deficiencies.

Celiac disease diagnosis requires a medical review of symptoms. Symptoms of celiac disease include: gas, diarrhea, stomach pain, fatigue, joint pain, weight loss, and dermatitis herpetiformis (skin rash). Diagnosing the disease also may require a blood test to identify elevated levels of certain autoantibodies and a biopsy of tissue from the small intestine. Although there is no cure for celiac disease, it can be successfully managed through appropriate treatment, which requires compliance with a gluten-free diet. Removing gluten from the diet allows the small intestine to heal, which improves nutrient absorption. Fortunately, there are plenty of foods that are naturally gluten free, such as fruits, vegetables, beef, poultry, fish, nuts, eggs, and more. A growing number of products are being developed by food companies in response to an increase in the demand for gluten-free products.

Understanding the T1D–celiac disease link

Research studies have provided information about why celiac disease can strike people with T1D. In fact, about 1 in 10 people with T1D, as noted above, also have celiac disease, compared with an estimated 1 in 100 for the general population. One connection between T1D and celiac disease is that the two conditions appear to share a common genetic origin. “There are similarities in the genes shared between the two diseases,” says David van Heel, M.D., Ph.D., a professor of gastrointestinal genetics at Barts and The London School of Medicine and Dentistry who is investigating T1D and celiac disease. (Professor van Heel estimates that 1 in 20 people with T1D in the UK also have celiac disease.) In a JDRF-funded research study, Professor van Heel and his scientific team linked seven chromosome regions that are shared between the two diseases. His research suggests that T1D and celiac disease may be caused by common underlying mechanisms. “The results were surprising, because we did not expect to see this very high degree of shared genetic risk factors. These findings suggest common mechanisms causing both celiac and type 1 diabetes,” reports Professor van Heel.

Yet the prevalence of celiac disease in people with T1D is leading researchers to focus more on the relationship between the two diseases. A recent study conducted at the Barbara Davis Center for Childhood Diabetes in Aurora, CO, found that nearly 33 percent of young people with T1D showed signs of celiac disease or other autoimmune disorders at the time of diagnosis.

Diagnosing celiac disease in people with T1D

Interestingly, many people with T1D and celiac disease do not suffer from the classic symptoms of celiac disease. “The majority of people we see who have both diseases don’t have celiac symptoms,” says Suzanne Simpson, R.D., a registered dietitian at the Celiac Disease Center at Columbia University in New York, NY. “If they are screened specifically for celiac disease, then they may notice the symptoms. But more and more people with T1D and celiac disease are being diagnosed without symptoms.” In these cases, a blood test plus an intestinal biopsy provides the confirmation of the celiac-disease diagnosis. “When you have chronic autoimmune disease like type 1 diabetes, you are managing a lot—food, insulin, blood testing, exercise, et cetera,” Ms. Simpson remarks. “Getting occasional stomach pain may not lead a person to think that something is wrong unless the symptoms are persistent and frequent.” Ms. Simpson herself has both diseases—she was diagnosed with T1D at age seven (she is now 42) and with celiac disease as a young adult. Caitlyn Carr, a JDRF 2011 Children’s Congress delegate, was diagnosed with celiac disease just five months after her diagnosis with T1D, at the age of seven. Her story of learning to balance two diets to manage the two conditions was published in this magazine last summer.

Dealing with a dual diet

For people with and without T1D who have celiac disease, the suggested treatment is a gluten-free diet. For those with T1D, this requires even more care in choosing carbs to support healthy blood-glucose levels. So how can people living with both diseases maintain good glucose control while avoiding gluten? We were fortunate to direct our questions to Ms. Simpson, who is well versed in the management of both diseases. “It’s all about making smart substitutions,” she advises. Read on for her roadmap for accomplishing just that.

Keep on counting carbs

“There are no specific changes when counting carbs for the two conditions,” Ms. Simpson says. “They are exactly the same principles. After initial diagnoses of celiac disease, people with T1D can eat more rice and potatoes instead of gluten-containing carbs, and then they can slowly transition to gluten-free breads and pastas,” she says. Ms. Simpson suggests weighing your food, instead of just measuring it, as a good strategy for accurately calculating carbs.

Monitor the impact of gluten-free products

Ms. Simpson points out that people with both T1D and celiac disease do not have to selectively purchase foods that are labeled “gluten free.” Foods such as vegetables, fruits, meats, poultry, fish, and dairy products are all naturally gluten free. Legumes such as dried peas, beans, and lentils are also gluten free and healthy additions to a T1D diet. Choosing substitutions for gluten-containing bread products and cereals requires a bit more work. “With gluten-free breads and cereals, you have to read these food labels carefully, because the majority of gluten-free substitution foods are high in carbs,” Ms. Simpson says. “So the impact of these foods on blood-sugar levels can be unpredictable in the beginning, and it is possible that insulin requirements will need to be adjusted to manage what you are eating.” (Note: Ms. Simpson emphasizes that grains and grain-containing products, cereals, and breads must be labeled “gluten free” because grains can be unintentionally contaminated with gluten.)

Shop smart

For smart food shopping, here’s what Ms. Simpson recommends for her patients at the Celiac Disease Center at Columbia University:

• Always read food labels.
• Wheat free does not mean gluten free.
• When in doubt, do without!
• Remember that food items in bulk bins cannot be guaranteed gluten free, due to possible contamination issues.
• Local health-food stores, gourmet-type grocery stores, and even many grocery-store chains often stock a variety of gluten-free foods.
• Gluten-free foods can be ordered online directly from many companies, such as Ener-G and Glutino. (Amazon sells many good gluten-free options.)

Keep in mind

People with T1D may notice a change in their blood-glucose control after starting a gluten-free diet. Removing gluten allows the lining of the gut to heal, so absorption of nutrients—including those ever-important carbohydrates—will improve. Special attention to blood-glucose levels may be needed until the body is accustomed to more efficiently absorbing nutrients. Some people may require more insulin, so it is important to keep your T1D healthcare team informed about how you are managing your diet and the impact on your blood-glucose levels.

Disclaimer:

The information in this article is offered for general educational purposes and is not intended to replace professional medical advice. You should not make any changes to the management of type 1 diabetes without first consulting your physician or other qualified medical professional.