You do if you have celiac disease or gluten sensitivity, a condition that doctors once dismissed but now recognize as legitimate. So says Stefano Guandalini, MD, director of the University of Chicago Celiac Disease Center.
Before you go gluten-free, there's something you should do first.
If you've noticed that you react badly to gluten -- with symptoms like diarrhea, stomach upset, abdominal pain, and bloating -- see a doctor to get tested for celiac disease. Do that before you start any gluten-free diet.
If you have celiac disease and you eat gluten, the lining of your small intestine becomes inflamed and gets damaged, making it harder for your body to absorb nutrients. That can lead to malnutrition and weight loss.
Getting diagnosed involves taking a blood test. Depending on the results, you would also get an intestinal biopsy.
"If you think you might have celiac disease, the biggest mistake is to begin a diet without being tested," Guandalini says.
Quitting gluten before you get the blood test for celiac disease might backfire. By the time you get tested, your immune system might not be making the antibodies that the test checks for.
"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 might delay getting diagnosed.
What Is Gluten Sensitivity?
What if you don't test positive for celiac disease but still react badly to gluten?
"These patients absolutely do exist," Guandalini says. "They do have real symptoms."
Unlike celiac disease, gluten sensitivity doesn't damage the intestine. There's no accepted medical test for gluten sensitivity, so you should tell your doctor about your symptoms.
"We have to believe the patient when they tell us that they actually have experienced side effects when they eat gluten," Guandalini says.
People with gluten sensitivity may have symptoms as severe as those of celiac disease, says Melinda Dennis, RD, co-author of Real Life with Celiac Disease and nutrition coordinator of the Celiac Center at Beth Israel Deaconess Medical Center in Boston.
Besides gastrointestinal symptoms, gluten-sensitive people often have fatigue and headaches, says Dennis, who has celiac disease.