April/May 2022 Issue

Gluten-Free Living: Gluten’s Impact on Autoimmune Diseases
By Lisa Andrews, MEd, RD, LD
Today’s Dietitian
Vol. 24, No. 4, P. 18

For clients diagnosed with celiac disease and nonceliac gluten sensitivity, following a gluten-free diet is a lifelong endeavor. When individuals with celiac disease ingest gluten, a protein in wheat, rye, and barley, they experience damage to the lining of their small intestine, leading to pain, nutrient malabsorption and deficiencies, and perhaps even an increased risk of some forms of cancer. Therefore, adherence to a gluten-free diet is vital to prevent intestinal damage and promote healing.

People with nonceliac gluten sensitivity, on the other hand, may experience intestinal symptoms but not intestinal damage when consuming gluten-containing foods.1

Emerging evidence suggests that a gluten-free diet may offer some relief for those with irritable bowel syndrome (IBS), type 1 diabetes, and other autoimmune conditions such as thyroid disease and rheumatoid arthritis. This article examines the impact gluten has on individuals with these conditions and whether following a gluten-free diet may help treat and manage them.

Gluten and Its Role in IBS
IBS is a functional bowel disorder that impacts an estimated 10% to 20% of the US population and is more common in women than in men. The cause of IBS isn’t clearly understood, but symptoms include abdominal pain, gas, bloating, and diarrhea, though some may experience constipation.2

Research suggests gluten may trigger IBS, as gut enzymes may poorly degrade the gluten protein gliadin and lead to an intrinsic immune response and inflammation.2

Research on the benefit of a gluten-free diet in IBS is mixed. A recent small study investigating the impact of a combined low-FODMAP and gluten-free diet on gut microbiota and IBS symptoms found that after six weeks, all 30 participants who completed the trial experienced significantly reduced IBS symptoms.3

In a double-blinded randomized controlled trial of 34 participants with IBS and without celiac disease, those who ingested gluten for one week after following a gluten-free diet for six weeks reported significantly worsened gastrointestinal symptoms, including abdominal pain, bloating, and changes in stool consistency, compared with the placebo group.4

In a similar study in India involving 60 participants who adhered to a gluten-free diet for four weeks, followed by four weeks of gluten reintroduction or placebo, those who consumed gluten reported greater severity of abdominal pain, bloating, and tiredness than did the placebo group.5

A more recent study of 103 participants found that ingestion of FODMAPs led to modestly higher IBS severity scores than intake of gluten or placebo alone. No differences were found between the placebo and gluten groups.6

Jamie Adams, MS, RD, LDN, RPYT, owner of Jamie Adams Health & Wellness, LLC, in Baltimore, says gluten-containing foods include carbohydrates called fructans that are fermented by gut bacteria and may cause IBS symptoms. “The low-FODMAP diet was designed to target common triggers of IBS. There’s some crossover between a gluten-free diet and a low-FODMAP diet. [But since a] low-FODMAP diet is more restrictive, clients accept and adhere to a gluten-free diet, and most report improvement in symptoms,” she says.

Gluten and Type 1 Diabetes
According to a systematic review, 4% to 5% of patients with type 1 diabetes also have celiac disease. Research has shown that the two conditions share a common genetic background of certain forms of human leukocyte antigen that predispose individuals to develop both. Killer immunoglobulin-like receptor genes, gut microbiota dysbiosis, and enteroviral infection in gut cells also have been implicated in raising the risk of developing celiac disease in patients with type 1 diabetes.7

In previous prospective studies, infants genetically predisposed to type 1 diabetes and celiac disease exhibit antibody positivity to both conditions in the first one to three years of life. Exposure to cow’s milk and gluten under four months of age and early viral infections have been identified in the development of each disease. Alterations in gut microbiome composition—through factors such as breast-feeding, diet, infections, antibiotics, and method of delivery at birth—are seen in both conditions and impact the risk of future autoimmune conditions.8

In other research, it’s been suggested that a gluten-free diet may help prevent type 1 diabetes. Gluten peptides are thought to cross the intestinal barrier and cause inflammation, and when these peptides reach the pancreas, they may alter beta cells, leading to changes in insulin secretion. Animal studies and one human study have shown that gluten-free diets during pregnancy may lower the risk of type 1 diabetes in children.9,10

Because excluding gluten-containing whole grains is likely to reduce dietary fiber intake, individuals with both type 1 diabetes and celiac disease may be at risk of metabolic syndrome, nonalcoholic fatty liver disease, and micronutrient deficiencies.10,11 As a result, individuals with both of these diseases should include other high-fiber grains such as brown rice, gluten-free oats, quinoa, millet, and buckwheat.

Toby Smithson, MS, RDN, LD, CDCES, FAND, a diabetes lifestyle expert and founder of DiabetesEveryDay.com, in Hilton Head, South Carolina, says that while people with type 1 diabetes are more likely to be diagnosed with celiac disease compared with the general population, not everyone with type 1 diabetes needs to follow a gluten-free diet. However, when counseling clients with type 1 diabetes and celiac disease, Smithson recommends gluten-free foods high in fiber such as gluten-free oatmeal, almonds, natural nut butters, beans, fruits, and vegetables. When purchasing beans, Smithson suggests clients check labels and avoid varieties containing wheat starch or wheat flour.

Gluten and Autoimmune Thyroid Disease
Gluten-free diets may help individuals with other autoimmune conditions, such as autoimmune thyroid disease (AITD). Some studies suggest there’s a connection between celiac disease and AITD, as well as between nonceliac wheat sensitivity and AITD. Rationale behind these associations is based on a cross-reaction of antibodies, malabsorption of nutrients needed for thyroid function, and increased intestinal permeability. Eliminating gluten has been advised because of possible interactions of gliadin with thyroid antigens.12,13

Jeanette Kimszal, RDN, NLC, New York–based co-owner of Thyroid Nutrition Educators, says that some “research shows a correlation between gut dysbiosis and thyroid conditions. A thyroid-gut-axis connects gut health to the immune system and thyroid function,” and gut dysbiosis “alters the immune system by promoting inflammation and lowering immune responses. This can also lead to an increase in intestinal permeability.”12

Researchers conducted a small study of 34 drug-naïve women with Hashimoto’s thyroiditis to explore whether a gluten-free diet impacted thyroid autoimmunity, hypothalamic-pituitary-thyroid axis activity, and thyroid function tests. The study divided the women into two groups: one that followed a gluten-free diet for six months and the other that received no dietary treatment. Serum levels of thyroid peroxidase, thyroid hormones, and vitamin D were measured at the start of the study and six months later. Results showed reduced thyroid antibody titers and slightly improved vitamin D levels in the gluten-free diet group, suggesting a gluten-free diet may be beneficial to women with AITD.14

In a study that analyzed evidence on the effect of gluten or a gluten-free diet on thyroid autoimmunity in those with Hashimoto’s thyroiditis and with or without celiac disease, researchers concluded that excluding gluten may increase the risk of Hashimoto’s thyroiditis development due to possible nutrient deficiencies linked with low-quality gluten-free products. Only a few studies suggested that a gluten-free diet would be beneficial for Hashimoto’s thyroiditis patients, even without celiac disease. The researchers concluded that the studies don’t support the assertion that patients with Hashimoto’s thyroiditis should eliminate gluten from their diet. The strongest connection between gluten and thyroid destruction, according to the researchers, seems to be based on molecular mimicry—when the body confuses glycoproteins in gluten for pathogens and attacks its own tissues.15

Gluten and Rheumatoid Arthritis
Individuals with rheumatoid arthritis, a chronic, painful autoimmune disease affecting the synovial joints, may see some benefit from a gluten-free diet. A study of 40 patients with obesity or overweight and with longstanding rheumatoid arthritis evaluated the impact of a three-month diet intervention. The diet excluded meat, gluten, and lactose and all dairy products (ie, the privative diet) and was compared with a control balanced diet including those foods.16

Participants on the privative diet showed improvement in overall physical and mental health. They experienced a significant reduction in systolic and diastolic arterial pressure, as well as a decrease in circulating leukocytes and neutrophils and high-sensitivity C-reactive protein, markers of inflammation.16

Researchers have found that observational and anecdotal cases cite an association between gluten and autoimmune diseases such as rheumatoid arthritis and surmise that gluten may have an inflammatory effect impacting the gut flora. In a case study that evaluated whether a gluten-free diet could manage inflammation and chronic rheumatoid arthritis symptoms in four patients, a gluten-free diet was associated with improved symptoms and remission, even in participants resistant to conventional drug therapies.17

Moreover, a recent narrative review on the ideal diet for the management of rheumatoid arthritis found that gluten-free foods, including whole grains, fruits and vegetables, low-fat and fat-free dairy, lean meats, fish, and legumes, as well as vitamin D and omega-3 fatty acid supplementation, were associated with reduced inflammation. Changes in gut flora due to gluten ingestion are suspected of increasing the risk and progression of rheumatoid arthritis.18

Recommendations for RDs
Dietitians will agree that counseling clients with autoimmune conditions—regardless of whether they also have celiac disease or nonceliac gluten sensitivity—often can be challenging. Individuals with IBS may be following a low-FODMAP diet and therefore additional restrictions will be necessary. Clients with rheumatoid arthritis are at risk of heart disease and osteoporosis, so dietitians should encourage them to eat lean meats and low-fat dairy products. And RDs should recommend foods containing adequate iron, selenium, and zinc for patients with thyroid disease.

Below are some examples of gluten-free foods dietitians can recommend for patients with IBS and the aforementioned autoimmune diseases.

• Whole grains can include gluten-free oats, brown rice, corn, millet, quinoa, and amaranth for dietary fiber.

• Low-FODMAP fruits and vegetables include citrus fruits, berries, cantaloupe, green beans, carrots, a variety of squashes, and potatoes.

• Low-fat or fat-free dairy products are important sources of calcium, vitamin D, B vitamins, and protein. RDs can recommend nonfat or low-fat yogurt, skim and 1% milk, nonfat or low-fat cottage cheese, and other low-fat cheeses.

• Legumes provide necessary fiber and protein without gluten. Lentils and dried and canned beans such as black, navy, pinto, and kidney beans are good choices.

• Fish and seafood provide protein, B vitamins, and omega-3 fatty acids. Good sources include salmon, tuna, mackerel, shrimp, crab, and scallops.

• Lean meat contains iron, zinc, and protein. Lean choices include skinless poultry, 90% (or higher) lean ground beef or turkey, and lean cuts of pork, such as tenderloin.

• Nuts and seeds provide heart-healthy fats, protein, vitamin E, zinc, and other nutrients. Walnuts, almonds, pistachios, pecans, and peanuts are good choices.

Final Thoughts
More research is needed on gluten-free diets associated with conditions beyond celiac disease and nonceliac gluten sensitivity alone. While maintaining a gluten-free diet may be expensive and limit fiber, iron, B vitamins, and other nutrients, it’s important for dietitians to treat patients individually and offer affordable solutions to obtain these nutrients in the aforementioned foods. If patients’ symptoms are reduced or improved on a gluten-free diet, they may be more inclined to stick with it and improve their digestive health long term.

— Lisa Andrews, MEd, RD, LD, is the owner of Sound Bites Nutrition in Cincinnati, where she shares her nutrition knowledge through freelance writing, cooking demos, and consulting. She’s a regular contributor to Food and Health Communications and the author of the Healing Gout Cookbook, Complete Thyroid Cookbook, and Heart Healthy Meal Prep Cookbook. To learn more about Andrews, visit soundbitesnutrition.com.

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