Celiac Disease vs. Gluten Intolerance: What’s the Difference?

Both are sensitive to gluten, but for very different reasons.

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Gluten-free options used to be contained to a couple shelves at the grocery store or the “salad” section of a restaurant menu. Today, gluten-free products and meals are more numerous, accessible, affordable, and delicious than ever.

For someone who doesn’t rely on these gluten-free offerings, it might be confusing to see the gluten-free section of the grocery store continuously grow. It’s a myth that a gluten-free diet is a weight-loss diet, or that it’s “healthier” than other diets. The truth is, a gluten-free diet is often a critical medical treatment.

There are many reasons someone might need to choose a bread made from gluten-free flours, or a pizza crust made from cauliflower. Two common reasons are celiac disease and gluten intolerance—two conditions that are often used interchangeably but are definitely not the same thing.

What Is Gluten Intolerance?

First things first: Gluten is a type of protein. It’s the thing that gives baked goods their shape and holds them together. You most commonly find gluten in wheat, rye, and barley, according to the Celiac Disease Foundation (CDF). Most people think of bread and pastries when they think of wheat, but gluten appears in unexpected foods.

In most people, gluten is effectively digested and is not harmful. But for some people, gluten is difficult to break down. This digestive disorder goes by many names: gluten intolerance, gluten sensitivity, or its formal name, non-celiac gluten sensitivity.

If someone has gluten intolerance, the gluten protein will pass into the colon undigested. This may cause the following symptoms, according to the CDF:

  • Brain fog

  • Fatigue

  • Upset stomach

  • Bloating

  • Diarrhea

  • Depression

  • Headaches

  • And joint pain.

Eating gluten may cause these symptoms in someone with a gluten intolerance, but it will not cause permanent damage to the digestive system. The person will also not test positive for celiac disease or for a wheat allergy.

Some people with gluten intolerance may opt for a strict gluten-free diet, while others may be able to tolerate small amounts of gluten. This is similar to lactose intolerance, in which some people are able to stomach some dairy in small quantities.

What Is Celiac Disease?

Celiac disease also involves an intolerance to the gluten proteins, but its pathology is a bit different. Celiac is an autoimmune disease, which means the immune system is fighting someone’s own body instead of attacking foreign viruses or bacteria.

In the case of celiac disease, the immune system is attacking and causing inflammation in the small intestine, according to the American Academy of Allergy, Asthma, and Immunology. This immune response occurs when the person eats gluten, even in trace amounts. (This is different than a wheat allergy, in which the immune system overreacts to wheat and causes potentially life-threatening symptoms within minutes of consumption.)

If gluten is consumed, someone with celiac disease may experience the following symptoms:

  • Stomach pain

  • Diarrhea

  • Pale and foul-smelling stool

  • Fatigue

  • Dental problems

  • Delayed growth

  • And damage to the small intestine.

The small intestine is lined with microscopic, finger-like projections called the villi. The villi normally help absorb nutrients from food while it passes through the small intestine.

If someone with celiac continues eating gluten, and thus suffers repeated attacks on the small intestine, these villi are damaged, and the small intestine lining begins to appear smooth. This means the small intestine is not adequately absorbing nutrients, and people with untreated celiac disease may suffer nutritional deficiencies.

Without adequate nutrient absorption, it’s common for people with celiac disease to suffer from osteoporosis, anemia, pancreatic insufficiency, and infertility.

Currently, the only treatment that’s shown to be effective is a strict gluten-free diet. That means not only avoiding eating gluten, but avoiding foods that were cooked or handled on the same surface as gluten. By avoiding gluten, the immune system does not attack the small intestine, which prevents painful symptoms and damage to the villi.

Whether someone has gluten intolerance or celiac disease, a registered dietitian skilled in treating gluten sensitivities can help you adapt to a gluten-free diet while getting all necessary nutrients. Thanks to the ever-growing options of gluten-free products in stores and restaurants, this treatment is easier than ever before—and tastier, too.