Celiac disease, a sensitivity to wheat gluten that can cause intestinal problems and diarrhea, has long been considered a rare condition. New research, however, suggests that it may actually be quite common. It is estimated that more than three-quarters of people living with celiac aren’t aware they have it; it has no symptoms in many people.
Gluten, found in wheat, rye, barley, and related grains, is the substance that gives dough its elasticity and allows bread to rise. It is made up of two proteins, one of which, gliadin, causes an immune reaction in as many as one in 105 Americans. In celiac patients, molecules in gliadin cause bowel inflammation, which damages the small intestine and harms absorption of nutrients. Celiac is particularly common in people with conditions such as type 1 diabetes, lupus, thyroid disease, Down syndrome, and colitis.
As mentioned, celiac is often asymptomatic; people with the condition seem perfectly fine, the inflammation not being severe enough to cause any discomfort or noticeable effects. In others it can produce abdominal gas or cramping, bloated stomach, fatty or greasy stool, chronic diarrhea, and constipation. In addition, malabsorption can lead to various symptoms of malnutrition, such as unexplained weight loss, fatigue, weakness, anemia, osteoporosis, and infertility. In some cases, the disease manifests as irritability or depression; in others, joint pain and muscle cramps.
Celiac is present from early childhood, and if undetected may present in children as failure to thrive or poor growth or, when the child is a little older, delayed puberty. Indeed, failure to thrive is not infrequently the first sign of the condition. Because it so often accompanies other illnesses, symptoms may be difficult to tease out from those of the other conditions—this is particularly a problem when the celiac patient also has lupus, since symptoms of lupus are so subtle and varied.
According to a recent study, as underdiagnosed as the disease is, nearly as many people—1.6 million—have adopted the gluten-free diet people with celiac require despite never having been diagnosed or shown any symptoms. Avoiding gluten has a number of purported benefits for people without celiac disease, though there’s no known scientific basis for many of those claims. At least some success stories may well be people with undiagnosed celiac with very mild and unusual symptoms.