After years of living with Type 1 diabetes, you’re a pro at counting carbohydrates and adjusting insulin doses. Over the past year, however, your diabetes has become difficult to control. You’ve experienced weight loss, frequent bouts of diarrhea, and fatigue. You’ve also had fluctuating blood glucose levels — both hypoglycemia and hyperglycemia — and needed frequent insulin adjustments. You don’t know what’s wrong, and what’s worse, your doctor — make that doctors — can’t explain your symptoms, either. They’ve suggested everything from irritable bowel disease to depression, but nothing seems to help.
Then one day, a friend mentions that a colleague of hers has a daughter who has Type 1 diabetes and celiac disease, or intolerance to gluten. Her symptoms were similar to yours until her doctor put her on a special, gluten-free diet. Now she’s fine — as long as she doesn’t eat the wrong foods.
You’ve never heard of celiac disease before, but you’re curious. What is this disease and what causes it? What foods are off-limits? Which are OK to eat? Most of all, how would giving up all gluten-containing foods affect your life and your diabetes control? Before you make another appointment with your doctor, you decide to do some research of your own.
What is celiac disease?
Celiac disease, sometimes called celiac sprue or gluten-sensitive enteropathy, is a hereditary, autoimmune disease in which the body launches an immune reaction when a person consumes gluten, a type of protein found in wheat, rye, barley, and possibly oats. For reasons still unknown to researchers, when people with celiac disease eat foods containing gluten, the immune system sees it as a toxin and launches an attack to prevent its absorption into the bloodstream. The effect of the attack is a flattening of the villi, the small, fingerlike projections on the lining of the small intestine through which nutrients are absorbed. This leaves the intestinal surface smooth, with less surface area for absorbing nutrients. In addition, when the villi flatten out, the digestive enzymes normally present on the villi are destroyed, so food passes through the gut unabsorbed.
Common symptoms of malabsorption include gas, bloating, diarrhea, and weight loss. Other symptoms may include fatigue, anemia, irritability, or depression. In many cases of undiagnosed celiac disease, however, there are no symptoms at all.
Malabsorption of nutrients can create serious deficiencies of the fat-soluble vitamins A, D, E, and K; of folate and vitamin B12; as well as of iron and calcium. In children, this can lead to delayed growth or short stature as well as delayed puberty. Long-term complications of untreated celiac disease include osteoporosis, fertility problems, and benign or malignant tumors of the small intestine. Vitamin and mineral supplements are an essential part of treatment when the intestinal damage, or villous atrophy, is first recognized.
Another autoimmune disease caused by gluten intolerance is dermatitis herpetiformis, which mainly involves the skin. A severe, itchy, blistering skin rash shows up, usually on the elbows, knees, buttocks, and back; in severe cases, the rash can be on any skin surface. Dermatitis herpetiformis is diagnosed by a skin biopsy, but if an intestinal biopsy is also performed, damage to the villi is usually found, although to a lesser degree than that which occurs in celiac disease. Usually, there are no digestive symptoms of dermatitis herpetiformis, but it is treated with a gluten-free diet as well as with medication for the rash.
Celiac disease can be more difficult to diagnose than dermatitis herpetiformis because its symptoms often mimic other digestive diseases such as irritable bowel disease, Crohn’s disease, ulcerative colitis, and intestinal infections. Complicating the matter is the fact that people with untreated celiac disease often develop lactose intolerance (the symptoms of which also include gas, bloating, and diarrhea) because of the damage to the intestinal villi. Lactose, the sugar in milk and other dairy products, is digested by the enzyme lactase, which is located on the villi. Usually, lactose intolerance disappears within about 2 to 12 months of starting a gluten-free diet. In some cases, however, a person remains lactose intolerant and must continue to avoid dairy products as well as gluten.
Once diagnosed, the only treatment of celiac disease is lifelong, complete elimination of gluten-containing foods from the diet. With gluten elimination, symptoms may disappear within a few days, but complete healing of the small intestine may take three to six months or, in some cases, up to two years. Eating even a small amount of gluten can make a person sick again. In a small percentage of people, a gluten-free diet does not improve symptoms; these people may need to be treated with steroids or immunosuppressive drugs.
Who gets this disease?
Celiac disease commonly shows up in children, but it has been diagnosed in people of all ages, mainly because not everyone with celiac disease experiences symptoms right away. In studies from several countries, including Scotland, England, the United States, and Canada, almost 50% of those with a new diagnosis of celiac disease did not experience symptoms. Several factors may influence the onset of symptoms in those genetically predisposed to the disease. It is believed that the longer an infant is breast-fed, the later the symptoms of celiac disease appear. (However, it is not known if breast-feeding can prevent celiac disease.) The age at which a person began eating gluten and how much gluten he consumes may also affect the onset of celiac disease. A bacterial or viral infection or the stress caused by pregnancy or surgery may trigger symptoms in susceptible individuals.
Since celiac disease is an inherited disease, all first-degree family members — parents, siblings, and children — of people with celiac disease should be screened. About 10% to 15% of first-degree family members will also have celiac disease. In addition, celiac disease often occurs in those with another autoimmune disorder, such as Type 1 diabetes, thyroid disease, Sjögren syndrome, rheumatoid arthritis, and Addison disease. Celiac disease is found in 5% to 7% of people who have Type 1 diabetes; some researchers recommend that all children with Type 1 diabetes be screened for celiac disease.
Women are about twice as likely to have celiac disease as men, and the disease is most common in people of European descent (the incidence is particularly high in Scandinavian countries, Italy, and Ireland). It is less common in those of African or Asian heritage. In countries where there is greater awareness of the disease, there is increased diagnosis. In Central Europe, 1 in 200 people has celiac disease. In Italy, every child is screened for celiac disease by age six; approximately 1 in 250 Italians has the disease. In the United States, celiac disease is largely unrecognized and underdiagnosed. While only about 150,000 Americans have been diagnosed with the disease, a recent study suggests that as many as 1 in 133 Americans may have celiac disease. Underdiagnosis of celiac disease is a serious concern, because the risk of long-term complications increases the longer it goes untreated.
Several blood tests have been developed that can be used to screen people who are at risk for celiac disease. The tests detect the presence of certain antibodies that occur in higher numbers in the blood of people with celiac disease. Antibodies are produced by the body to recognize and fight off antigens or toxins. In people with celiac disease, there are elevated amounts of antigliadin, antiendomysium, and antireticulin antibodies (gliadin, endomysium, and reticulin are the proteins and fibers found in wheat, barley, and rye). A blood test for the antibody to tissue transglutaminase (the specific part of endomysium to which the antibody reacts) was developed that is highly sensitive and accurate about 99% of the time, making it helpful for screening at-risk groups. However, the gold standard for confirming a diagnosis of celiac disease if preliminary blood tests are positive is still an intestinal biopsy, in which a long, thin tube called an endoscope is threaded through the mouth and stomach to the small intestine to take a small tissue sample. If the biopsy reveals villous atrophy, a diagnosis of celiac disease is established. If your doctor suspects celiac disease, you should continue to eat gluten-containing foods until after the biopsy. It is much more difficult to diagnosis celiac disease if gluten has been removed from the diet and healing has already started.
The only treatment for celiac disease is a lifelong, 100% gluten-free diet. Foods that contain gluten are any derivative or variation of wheat, rye, or barley, including bulgur, couscous, triticale, spelt, einkorn, farina, graham flour, semolina, and durum wheat. Until recently, people with celiac disease were told they could not eat oats, but some studies show that oats are not toxic to most people with celiac disease. However, since there is still a debate over this (and there is a strong possibility of gluten from other grains contaminating oats during harvesting, milling, or processing), it is probably best that people with celiac disease not consume oats.
Obvious foods to avoid on a gluten-free diet are most pizzas, breads, bagels, crackers, cookies, cakes, pies, gravies, and flour-based sauces. But there are many less obvious sources of gluten. Communion wafers contain gluten; cooking sprays may contain grain alcohol; malt and malt flavoring, found in cereals, syrups, and beer, are usually made from barley (although some malt products are made from corn). Many licorice candies contain gluten. For this reason, it is very important to read the ingredients list on the label of every food product you purchase and to scrutinize the fine print right down to the food colorings, seasonings, preservatives, and thickeners, many of which contain gluten.
Reading the label may not be enough, however, since some sources of gluten may not be listed on the label. Gum wrappers, for instance, are sometimes dusted with flour to prevent sticking. What’s more, manufacturers sometimes change the way a product is made. Food that was gluten-free last month may have different ingredients this month. The only way to be sure about a product is to call or write the manufacturer. The manufacturer’s name, address, and telephone number appear on the food label. When calling a manufacturer, have the lot number of the food in question available. Many manufacturers also provide lists of their gluten-free foods.
After a while, you will learn to recognize suspect foods and ingredients, but a general rule of thumb is, “If you don’t know what’s in it, don’t eat it.” In the United States, at least, the word “starch” on a food label indicates cornstarch, which is safe to eat. “Modified food starch” or “modified starch,” on the other hand, could be made from corn, arrowroot, tapioca, or wheat. Hydrolyzed vegetable protein, textured vegetable protein, or hydrolyzed plant protein is usually made from wheat or wheat mixed with soy or corn. Vanilla and other flavoring extracts, prebasted turkeys, canned and dried soups, sauces, gravies, luncheon meats, caramel coloring, and soy sauce made from fermented wheat can all contain sources of gluten. Gluten is even used in nonfood items, such as some medicines, toothpastes, mouthwashes, and the glues on mailing labels and envelopes. Ask your pharmacist if any of your medicines contain gluten. Again, calling the manufacturer of a product to ask if it is totally gluten-free is a good habit to get into.
What to eat
By now you are wondering if there is anything that people with celiac disease can eat. Plain meats, fruits, vegetables, and most dairy products are all gluten-free, as long as they have not been breaded or cooked in the same pan with food that has been breaded. Likewise, corn, grits (made from corn), rice, potatoes, arrowroot, tapioca, beans, nuts, most soy products (except soy sauce), flaxseed, buckwheat (which is not actually a cereal but the seed of a flowering plant), sorghum, amaranth, quinoa, millet, and teff can be included in your meal plan. Packaged gluten-free cakes, cookies, waffles, pancakes, and pizza crust, as well as a wide variety of gluten-free baking mixes are available from specialty stores, some mainstream grocery stores, or from online or mail-order food companies. There are also bean, rice, and nut flours, which can be substituted in recipes that call for wheat flour. Mixing two or more types of flours when substituting for wheat flour gives the product a better texture. A gluten-free cookbook will give you tips for mixing flours and making conversions. These flours should be kept tightly sealed and stored in the refrigerator to prevent rancidity.
Since even a small amount of wheat, rye, or barley can set off a reaction, it’s important to keep foods strictly segregated in households where those who don’t have celiac disease consume those grains. If anyone in the household uses wheat flour in cooking or baking, be aware that it can remain in the air for up to 24 hours. It can also remain on hands that are not washed thoroughly. Cooking utensils that have touched foods containing gluten must be cleaned carefully before preparing gluten-free food. Difficult-to-clean items such as a flour sifter should not be used to sift both wheat flour and gluten-free flour. Even using a toaster that has crumbs from a piece of wheat bread can contaminate gluten-free bread.
When ordering fried food in a restaurant, be sure to ask whether any foods that have a breaded coating have been cooked in the oil your food will be cooked in. Request that your food be cooked in a separate pan to be on the safe side.
There are several national organizations that provide information on celiac disease and foods to eat or avoid. A list of these organizations is provided here. Joining a celiac support group in your area can provide you with emotional support, up-to-date information, and new meal ideas. Gluten-free cookbooks can help you find tasty recipes and provide you with tips on how to substitute gluten-free products in your favorite dishes. (See “For Further Reading and Information” for a collection of resources on gluten-free living.)
Celiac disease with Type 1 diabetes
In people with Type 1 diabetes, malabsorption of nutrients from undiagnosed celiac disease can lead to frequent, unexplained low or high blood glucose readings. Insulin needs are frequently lower during the time before diagnosis. Once treatment of celiac disease has begun and nutrients are better absorbed, insulin doses may need to be adjusted. Treating celiac disease should make it easier to keep diabetes under control. A study published in the July 2002 issue of the journal Diabetes Care found that in children with Type 1 diabetes and celiac disease, 12 months of a gluten-free diet not only improved their growth but led to a significant reduction in HbA1c level (indicating improved blood glucose control).
For people with diabetes and celiac disease, starting a gluten-free diet requires learning the carbohydrate content of new, gluten-free foods, so they can be introduced into a meal plan or so that insulin doses can be adjusted accordingly. (Click here for information about the carbohydrate content of various gluten-free foods.) In basic carbohydrate counting, one serving of carbohydrate is 15 grams of carbohydrate. For those who adjust their insulin doses based on the amount of carbohydrate they eat, it is important to know exactly how many grams of carbohydrate are in a serving of food. A registered dietitian can help you figure this out and make adjustments to your meal plan or insulin regime.
Nutrition software programs can also help you analyze foods and recipes for carbohydrate content per serving. The United States Department of Agriculture Web site is a good source of nutrition information. There are also books on carbohydrate counting that may be helpful. Don’t forget to check the serving size on food labels and to assess how many servings you are actually eating. Since fiber is not digested or absorbed, you can subtract the grams of fiber from the total carbohydrate on the label if there are more than 5 grams of fiber per serving. When substituting new, gluten-free ingredients into your favorite recipes, add up the carbohydrate grams in each ingredient and divide by the number of servings the recipe yields. Write this information on your recipe cards so you will only have to do these calculations once.
Straying from a gluten-free diet — even just a little bit — can trigger the immune system reaction that damages your intestines, whether or not you experience symptoms. Just as adjusting to diabetes requires changing eating patterns and lifestyle habits, learning to prepare and enjoy gluten-free foods — and avoid gluten — can be a challenge at first, but it doesn’t have to mean a lifetime of tasteless meals. The variety and availability of gluten-free foods is greater now than ever before, and food manufacturers and even restaurants are becoming increasingly sensitive to the needs of people with food intolerances. Moreover, omitting gluten may introduce you to a rich variety of “alternative” grains, nuts, and seeds that are not only flavorful, but also rich in vitamins, minerals, protein, and fiber. In the end, better health, higher energy, and improved blood glucose control are worth the effort of adjusting to your new meal plan.