Researchers stumped about the rise in celiac disease
Celiac disease, a gastrointestinal disorder characterized by an intolerance to gluten, a grain protein, is on the rise in the U.S. and no one is quite sure why. But increasing amounts of people are being diagnosed yearly, prompting researchers to inquire as to the possible causes.
According to one recent study, nearly five times as many people have celiac disease today than they did during the 1950s. Another report found that the rate of celiac disease has doubled every 15 years since 1974 and is now believed to affect one in every 133 U.S. residents. "It's quite widespread," said Dr. Alessio Fasano, director of the Center for Celiac Research and the Mucosal Biology Research Center at the University of Maryland School of Medicine. "We thought there were regional differences in the past, but now we know it's everywhere."
Researchers are testing a number of hypotheses about the new trend. Celiac disease is an inherited autoimmune disorder that causes the body's immune system to attack the small intestine, according to the U.S. National Institutes of Health and the University of Chicago Celiac Disease Center. The attack is prompted by exposure to gluten, a protein found in such grains as wheat, rye and barley.
The autoimmune attack damages the inner lining of the small intestine, compromising its ability to digest food and extract vital nutrients. People afflicted with celiac disease can end up malnourished and suffering from bloat, vomiting, diarrhea or constipation. Adults with the disorder who do not have these dramatic symptoms may develop anemia, fatigue, osteoporosis or arthritis.
Awareness of celiac disease has grown over the last decade, as has a market for many gluten-free foods in response to that awareness. But researchers don’t believe that the increase in diagnoses is simply due to greater awareness, or the concomitant “ferreting out” of the diagnoses by overly health-conscious patients. Rather, scientists increasingly believe that celiac disease is on the rise probably for the same reason other autoimmune diseases are on the rise: our overly clean and sanitized Western environment.
According to the "hygiene hypothesis," said Carol McCarthy Shilson, executive director of the University of Chicago Celiac Disease Center, people in industrialized countries are more at risk for celiac disease because their bodies have not had to fight off as many diseases. "We're just too clean a society, so our immune systems aren't as developed as they should be," she said.
The hypothesis has been voiced in allergy circles. Researchers studying the increasing incidence of animal and air particle allergies also have suggested that an overly clean environment in infancy and early childhood may be to blame. There are even studies which suggest that having a pet as a baby or toddler may significantly reduce one’s risk of developing allergies and asthma.
Another version of the hypothesis holds that the cleanliness of industrialized society has caused a fundamental change in the composition of the digestive bacteria contained within the gut, Fasano said. "It's because this increase occurs primarily in industrialized countries, where things are cleaner," Fasano said. "We abuse antibiotics, we wash our hands too often, we are vaccinated more often."
Other potential culprits in the rise in gluten intolerance include:
An increase in the amount of gluten in grains. Grains are allegedly far more dense in gluten than they were a century ago. How that has happened has not been explained. Have we altered the genetic composition of grains, or have we selectively bred out the less gluten-dense varieties? I would add that many foods, not just grain foods, have ADDED gluten protein in them, in order to make them denser or richer in taste. Some of the offenders include some processed peanut butter products and vegetarian “meats,” which seem to be a blend of tofu and isolated or hydrolyzed grain proteins, such as soy and wheat.
Children being exposed to gluten too early. Infants should not be exposed to too many grain proteins in their first year. The principle is the same as limiting their exposure to peanut butter. Research shows that a delay in exposure diminishes the likelihood of developing an ellergy.
Related to the above, too few women breastfeeding their infants, especially extended breastfeeding throughout their children’s first year. Some studies suggest breastfeeding is protective. No one is sure how, but it may be a combination of factors, such as prevention of early exposure and immunologic factors in the breast milk itself.
About thirty percent of the population carries the gene which makes them vulnerable to developing celiac disease. Many adults with celiac disease don't suffer the digestive symptoms associated with gluten intolerance, so they are unaware that they have it or could pass it on. "About two-thirds of people with the active disease have no symptoms at all," Shilson said.
Studies also have found that the earlier people find out they have celiac disease, the better able they are to head off the disorder's more debilitating effects.
"There's not much you can do to prevent it, but you can be aware of it and catch it," Shilson said. "Early intervention is key."