Celiac disease and lactose intolerance are distinct digestive conditions, yet they often present with similar uncomfortable symptoms. Celiac disease is an autoimmune disorder where consuming gluten, a protein found in wheat, barley, and rye, triggers an immune response that damages the small intestine. Lactose intolerance is the inability to fully digest lactose, a sugar present in dairy products, due to insufficient production of the enzyme lactase. This article explores how celiac disease can lead to lactose intolerance.
What is Celiac Disease
Celiac disease is an inherited autoimmune disorder affecting the small intestine. When individuals with celiac disease consume gluten, their immune system attacks the lining of their small intestine. This attack targets the villi, tiny, finger-like projections. The villi are responsible for absorbing nutrients from digested food.
In celiac disease, the immune response to gluten causes these villi to become flattened or destroyed, a condition known as villous atrophy. This damage significantly reduces the surface area for nutrient absorption, leading to malabsorption and potential nutritional deficiencies.
How Celiac Disease Leads to Lactose Intolerance
Damage to the small intestinal villi in celiac disease directly impacts the body’s ability to digest lactose. The enzyme lactase, which breaks down lactose into simpler sugars for absorption, is primarily produced at the tips of these villi. When the villi are damaged due to villous atrophy, lactase production is impaired or ceases.
This reduction or absence of lactase leads to secondary lactose intolerance, meaning it develops as a consequence of another condition. Undigested lactose then passes into the large intestine, where it is fermented by bacteria, causing digestive symptoms. This form of lactose intolerance is often temporary; as the small intestine heals on a gluten-free diet, lactase production can resume, resolving the lactose intolerance.
Identifying Symptoms and Confirming Diagnosis
Recognizing the symptoms of both celiac disease and lactose intolerance can be challenging, as many symptoms overlap. Common symptoms of celiac disease include abdominal pain, bloating, chronic diarrhea, fatigue, and weight loss. Some individuals with celiac disease may also experience anemia, mouth ulcers, or a skin rash known as dermatitis herpetiformis. Symptoms of lactose intolerance typically appear 30 minutes to two hours after consuming dairy and include bloating, gas, stomach cramps, and diarrhea.
Due to the overlap in symptoms, professional medical diagnosis is necessary to differentiate and confirm each condition. Diagnosing celiac disease usually begins with blood tests that check for specific antibodies, such as tissue transglutaminase IgA (tTG-IgA). For accurate results, individuals must be consuming gluten during these tests. A positive blood test is typically followed by an endoscopy with a biopsy of the small intestine to confirm villous atrophy. For lactose intolerance, diagnostic tests include the hydrogen breath test, where high levels of hydrogen in the breath after consuming lactose indicate malabsorption. A lactose tolerance test, which measures blood glucose levels after lactose intake, or a stool acidity test for infants, can also be used.
Living with Both Conditions
Managing both celiac disease and secondary lactose intolerance primarily centers on treating celiac disease. The treatment for celiac disease is strict, lifelong adherence to a gluten-free diet. Eliminating gluten allows the damaged small intestine to heal, which can take several months for children and several years for adults. As the intestinal lining recovers, lactase production can improve, often leading to the resolution of secondary lactose intolerance.
For persistent lactose intolerance, or while the intestine is healing, dietary modifications are beneficial. This includes reducing or avoiding foods high in lactose, choosing lactose-free dairy alternatives, or incorporating lactase enzyme supplements before consuming dairy products. Consulting with healthcare providers and registered dietitians is recommended to develop personalized dietary plans and ensure proper nutrient intake, especially since dairy products are a source of calcium and vitamin D.