(Guest Post) A Tutorial: How Celiac Disease and Lactose Intolerance Are Related
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This is a guest post written by Jeanette N. Keith, MD, who serves as Director of Gastroenterology and Bariatric Medicine at Cooper Green Mercy Hospital in Birmingham, AL. Prior to her appointment at Cooper Green Hospital, Dr. Keith was an Assistant Professor of Medicine in the section of Gastroenterology/Hepatology at the University of Chicago and Associate Professor of Nutrition Sciences and Medicine at the University of Alabama at Birmingham. To learn more about Dr.Keith, check out her full bio here.
May was National Celiac Awareness Month, emphasizing the importance of understanding celiac disease and its consequences. Calling attention to celiac disease also increases awareness of its complications – namely osteoporosis and lactose intolerance. People with celiac disease are at increased risk for osteoporosis, according to a recent news release from Loyola University physicians, because they often malabsorb important bone-building nutrients: calcium and vitamin D. In addition, damage to the intestinal lining in celiac patients may render them temporarily lactose intolerant. Therefore, when individuals present with gastrointestinal (GI) distress, it is important to make an appropriate diagnosis in order to avoid diet-preventable malnutrition and nutrient loss.
Celiac disease is an autoimmune disorder that results when there is an inflammatory or allergic response to gluten, a protein found in wheat, rye, barley and gluten-contaminated oats. (Note that pure oats may be tolerated, but inclusion in the diet should be discussed with a health professional.) It is characterized by antibody formation, mucosal inflammation, and damage to or loss of the villus in the duodenum and jejunum. Villi are specialized intestine cells on the lining of the small bowel that allow nutrients to be absorbed. These cells also produce enzymes required to digest certain nutrients, such as lactose.
Normal nutrient absorption occurs primarily in the small intestine and is site specific. For example, nutrients such as iron, calcium, and vitamin D are preferentially absorbed in the duodenum―or first portion of the small intestine―whereas folate and the milk sugar, lactose, are absorbed primarily in the jejunum or second portion of the small bowel. Therefore, any disease or medication that damages the villi will negatively influence nutrient absorption.
Patients often present with non-specific symptoms such as diarrhea, constipation, abdominal cramps, iron deficiency anemia, malabsorption, osteoporosis or abnormal liver function tests. Commonly, celiac patients present with iron, calcium and vitamin D deficiencies. Diagnostic studies to confirm the presence of celiac disease include testing for the antibodies to gluten, genetic testing and the gold standard, biopsy of the lining of the small bowel.
Treatment for celiac disease requires removal of gluten from the diet for life. However, because gluten is present in so many foods, and even medicines, compliance with a strict gluten-free diet is often difficult, and I usually recommend consultation with a registered dietitian. Strict adherence to a gluten-free diet prevents complications, such as small bowel malignancies, and allows the affected person to have normal nutrient absorption. Recovery or healing of the small bowel may take as long as 6 months to 2 years after a person begins consuming a gluten-free diet.
Dairy foods such as milk, most yogurts and most cheeses are naturally gluten-free foods as are dairy ingredients, such as whey protein and contain many of the at-risk nutrients for patients with celiac disease. Some dairy foods (i.e., certain cheese spreads or ice creams) may have flavorings or additives that contain gluten, so label reading is essential.
In contrast, lactose intolerance is not an inflammatory condition, but occurs when there is an insufficient amount of the enzyme, lactase, to digest all of the milk sugar present in the small intestine at any one time. When excess milk sugar reaches the colon, gut bacteria break down the milk sugar. Their breakdown products cause GI distress in some individuals.
When inflammation is present in active celiac disease, the villi are damaged and lactase activity level declines such that some celiac patients may not tolerate dairy foods in their diet until their gut is healed. This is known as “secondary lactose intolerance” as it is a reversible cause of lactose intolerance. When the celiac disease is very active, I generally recommend avoiding any food that worsens symptoms including dairy foods. However, to protect the nutritional health of the individual and minimize long-term nutritional complications, yogurt, natural cheeses and foods containing low amounts of lactose are re-introduced early, consumed in divided amounts throughout the day. Examination of the diet for hidden gluten and re-evaluation by a medical professional are indicated if symptoms persist or worsen.
Lactase activity typically returns to near normal levels three to four weeks after mucosal healing on a gluten-free diet such that dairy foods in the diet should be encouraged when symptoms abate and are generally well tolerated. Just as one begins slowly when beginning a high fiber diet, the re-introduction of dairy foods should be a gradual process. Inclusion of two to three servings per day of dairy foods in the diet of celiac patients is an important way to help prevent deficiencies of calcium and vitamin D, and to reduce the risk of osteoporosis and calorie-protein malnutrition.
For more information about primary lactose intolerance and its management, see the Lactose Intolerance Health Professional Education Kit, on the National Dairy Council website.
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