Rates of celiac disease -- a condition where people's immune systems react to gluten found in wheat, rye and barley -- increased between 2000 and 2004, but then stayed nearly the same from 2004 onward, according to a new study.
Reuters first reported on the study, published in the American Journal of Gastroenterology, which gives a nationwide look at celiac disease rates from a representative sample of people in Olmsted County, Minnesota.
For the study, researchers examined celiac disease rates in this region from 2000 to 2010, during which 249 people were diagnosed with the condition.
At the start of the study -- between 2000 and 2001 -- 11.1 out of every 100,000 people had celiac disease. Toward the end of the study -- between 2008 and 2010 -- it was up to 17.3 out of every 100,000 people. But researchers noted that the incidence of celiac disease plateaued after 2004.
"We believe that only about 5 [percent] of people with celiac disease know they have it," Dr. Stefano Guandalini, M.D., director of the Celiac Disease Center at the University of Chicago, told WebMD. "Many of these people have no symptoms, but many do have symptoms that are not recognized for what they are."
According to the most current estimations, from a 2012 study from Mayo Clinic researchers, 1 percent of adults in the U.S. have celiac disease, CBS News reported.
Celiac disease symptoms include diarrhea and abdominal pain, according to the Mayo Clinic. These symptoms occur when a person consumes gluten and the immune system of the small intestines overreacts to it, the Mayo Clinic explained. Eventually, celiac disease can lead to damage of the villi of the small intestine, which are important in absorption of key nutrients. There is no cure for celiac disease, but people with the condition can manage the disease by avoiding eating gluten.
According to a position paper published last year in the journal Annals of Internal Medicine, there are a lot of people who don't have celiac disease who still avoid gluten in their diets, even though their immune systems don't have any particular sensitivity to gluten.
"'Sense' should prevail over 'sensibility' to prevent a gluten preoccupation from evolving into the conviction that gluten is toxic for most of the population," wrote the paper’s authors, Dr. Antonio Di Sabatino and Dr. Gino Roberto Corazza, both of the University of Pavia in Italy. "We must prevent a possible health problem from becoming a social health problem."
Most recently, survey results released earlier this month show that nearly a third of people in the U.S. are trying to cut gluten out of their diets, NPR reported.