(HealthDay News) -- New research suggests that 1.4 million Americans have celiac disease but don't realize it, while 1.6 million people are on gluten-free diets -- a treatment for celiac disease -- even though they might not need it.
The findings, which estimate that 1.8 million Americans have celiac disease -- an autoimmune condition -- suggest that a whopping 78 percent of sufferers don't realize they have the condition.
"This provides proof that the disease is common in the United States," said study co-author Dr. Joseph Murray, a gastroenterologist at the Mayo Clinic, in a clinic news release. "If you detect one person for every five or six [who have it], we aren't doing a very good job detecting celiac disease."
People with celiac disease have trouble digesting wheat, rye and barley. A gluten-free diet can help, but about 80 percent of people on such a diet haven't been diagnosed with celiac disease.
"There are a lot of people on a gluten-free diet, and it's not clear what the medical need for that is," Murray said. "It is important if someone thinks they have celiac disease that they be tested first before they go on the diet."
The researchers came to their conclusions by examining blood-test results and the findings of a national survey.
Celiac disease appears to be especially common in white people.
"Virtually all the individuals we found were non-Hispanic Caucasians," said study co-author Dr. Alberto Rubio-Tapia, a Mayo Clinic gastroenterologist, in the news release. But, he said, the results are head-scratching because research in Mexico has suggested celiac disease is common there.
The research was funded in part by the U.S. National Institutes of Health and the U.S. Centers for Disease Control and Prevention.
The study appears July 31 in the American Journal of Gastroenterology.