What to know about celiac disease, gluten sensitivity, and gluten-free diets.
A Test for Gluten Sensitivity?
Because gluten sensitivity isn’t yet well understood, Carol has worried that people won’t believe her. Though celiac disease can be diagnosed through a blood test and an intestinal biopsy that shows damage to the villi, there’s no reliable test for gluten sensitivity. The intestine remains normal in appearance, so even a biopsy isn’t useful.
Rather, for gluten sensitivity, “the diagnosis rests on history,” Guandalini says. “We have to believe the patient when they tell us that they actually have experienced side effects when they eat gluten.”
Get Tested for Celiac Disease First
On one point, experts are emphatic: If you think you react badly to gluten, see a doctor for celiac testing before you start any gluten-free diet. “One has to first rule out and investigate celiac disease,” Guandalini says. “We are very passionate about that. If you think you might have celiac disease, the biggest mistake is to begin a diet without being tested.”
The blood test for celiac disease is very sensitive, he says, but a person needs to be eating gluten for the test to detect antibodies that indicate celiac disease.
“The test really has to be done before [quitting gluten]. If you don’t do the test and begin the diet, your antibodies slowly but progressively decrease and become normal within 3 to 6 months,” Guandalini says. That means that a celiac diagnosis can be missed or delayed, especially if the person hesitates to start eating gluten again in order to go through testing.
Eliot has seen many people diagnose themselves as gluten-sensitive and embark on gluten-free diets without getting tested for celiac disease first. But ruling out celiac disease “is what you have to do for your sake and your family’s sake,” she says, because the disease can run in families.
Do Gluten-Free Diets Help Gluten-Sensitive People?
Yes, Dennis says. When gluten-sensitive patients come to her clinic, they’ll still go on a gluten-free diet even if they don’t have celiac disease. “I teach them the same way because the symptoms can mimic celiac symptoms perfectly, and that can be an absolutely miserable life,” she says.
Do these patients need to follow a gluten-free diet as strictly as celiac patients? It’s not clear, Dennis says. “There’s no hard science to say that you must follow it in the exact same, strict, adherent way as someone with celiac disease does.”
But they usually improve on the diet, she says, often dramatically. Carol, for example, feels so much better that she tries to avoid all gluten. “It’s not worth the risk,” she says.
Benefits of Gluten-Free Diet Unproven for Other Conditions
Eliot, the celiac patient, went on to co-found the Gluten Intolerance Group of North America. She believes that a gluten-free diet might even help people with migraines, ADHD, and Down syndrome, she says.
But right now, there’s no evidence that a gluten-free diet helps with these other conditions, Guandalini says.
Nor does it aid weight loss, experts say. “There’s a misconception that it’s very, very healthy and you’re automatically going to lose weight on it,” Dennis says. “Not true. It’s not necessarily healthy. It has to be done properly.”
She warns that eating gluten-free can cause deficiencies in iron, vitamin B12, vitamin D, magnesium, fiber, and other nutrients because people are avoiding breads, cereals, and grains that are fortified. In contrast, many gluten-free products are not fortified, Guandalini says.
Be careful when choosing from the growing number of gluten-free products on the market shelves, Dennis says. They’re typically higher in carbohydrates, fat, and sodium and lower in fiber. “They’re trying to mimic the gluten-containing counterparts,” she says. Instead, people can bake a healthier bread at home, one that’s higher in fiber and protein and made with gluten-free grains that have been certified to be uncontaminated and gluten-free, such as quinoa, amaranth, or millet.