On a gluten-free diet, you do not eat wheat, rye, and barley. These foods contain gluten, a type of protein. A gluten-free diet is the main treatment for celiac disease. Some people believe a gluten-free diet can also help improve other health problems, but there is little research to support this idea.

Celiac and gluten

People follow a gluten-free diet for a number of reasons:

Celiac disease. People with this condition cannot eat gluten because it triggers an immune response that damages the lining of their GI tract. This response causes inflammation in the small intestine and makes it hard for the body to absorb nutrients in food. Symptoms include bloating, constipation, and diarrhea. Over time, weight loss, malnutrition, and vitamin deficiency can occur.

Gluten sensitivity. People with gluten sensitivity do not have celiac disease. Eating gluten causes many of the same symptoms as in celiac disease, without the intestinal damage.

Gluten intolerance. This describes people who have symptoms and may or may not have celiac disease. Symptoms include cramping, bloating, nausea, and diarrhea.

If you have one of these conditions, a gluten-free diet will help control your symptoms. It also helps prevent health problems in people with celiac disease. If you suspect you have one of these conditions, talk with your health care provider before making any diet changes.

Other health claims. Some people go gluten-free because they believe it can help control health problems such as headaches, depression, long-term (chronic) fatigue, and weight gain. However, these claims are unproven.

Because you cut out a whole group of foods, a gluten-free diet can cause you to lose weight. However, there are easier diets to follow for weight loss. People with celiac disease often gain weight because their symptoms improve.

On this diet, you need to learn which foods contain gluten and avoid them. This is not easy, because gluten is in many foods and food products.

Many foods are naturally gluten-free, including:

• Fruits and vegetables
• Meat, fish, poultry, and eggs
• Beans
• Nuts and seeds
• Dairy products

Other grains and starches are fine to eat, as long as they do not come boxed with seasonings:

• Quinoa
• Amaranth
• Buckwheat
• Cornmeal
• Millet
• Oats (that have not been processed with gluten-containing grains)
• Rice

You can also buy gluten-free versions of foods such as bread, flour, crackers, and cereals. These products are made with rice and other gluten-free flours. Keep in mind that they are often higher in sugar and calories and lower in fiber than the foods they replace.

When following this diet, you must avoid foods that contain gluten:

• Wheat
• Barley (this includes malt, malt flavoring, and malt vinegar)
• Rye
• Triticale (a grain that is a cross between wheat and rye)

You must also avoid these foods, which contain wheat:

• Bulgur
• Couscous
• Durum flour
• Farina
• Graham flour
• Kamut
• Semolina
• Spelt

Note that "wheat free" does not always mean gluten free. Many foods contain gluten or traces of wheat. Read the label and only buy "gluten free" options of:

• Bread and other baked goods
• Pastas
• Cereals
• Crackers
• Beer
• Soy sauce
• Seitan
• Breading
• Battered or deep-fried foods
• Oats
• Packaged foods, including frozen foods, soups, and rice mixes
• Salad dressings, sauces, marinades, and gravies
• Some candies, licorice
• Some medicines and vitamins (gluten is used to bind the pill ingredients together)

A gluten-free diet is a way of eating, so exercise is not included as part of the plan. However, you should exercise for at least 30 minutes a day on most days for good health.

People with celiac disease must follow a gluten-free diet to prevent damage to their intestines.

Avoiding gluten will not improve your heart health if you do not eat healthy foods. Be sure to substitute plenty of whole grains, fruit, and vegetables in place of gluten.

Many foods made with wheat flour are fortified with vitamins and minerals. Cutting out wheat and other grains can leave you short of nutrients like these:

• Calcium
• Fiber
• Folate
• Iron
• Niacin
• Riboflavin
• Thiamin

To get all the vitamins and minerals you need, eat a variety of healthy foods. Working with your provider or a dietitian can also help ensure you get proper nutrition.

Because so many foods contain gluten, this can be a hard diet to follow. It can feel limiting when you shop or eat out. However, as the diet has become more popular, gluten-free foods have become available in more stores. Also, many restaurants are now offering gluten-free meals.

The National Institutes of Health has a Celiac Awareness Campaign at celiac.nih.gov with information and resources.

More information and support for people with celiac disease, gluten sensitivity, and gluten-free cooking can be found at:

• Beyond Celiac -- beyondceliac.org
• Celiac Disease Foundation -- celiac.org

There are also a number of books on gluten-free eating. Your best bet is to find one written by a dietitian.

If you think you may have celiac disease or gluten sensitivity, talk with your provider. You should be tested for celiac disease, which is a serious condition.

If you have symptoms of gluten sensitivity or intolerance, do not stop eating gluten without first getting tested for celiac disease. You may have a different health condition that a gluten-free diet cannot treat. Also, following a gluten-free diet for several months or years may make it more difficult to accurately diagnose celiac disease. If you stop eating gluten before being tested, it will affect the results.

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Rubio-Tapia A, Hill ID, Kelly CP, Calderwood AH, Murray JA; American College of Gastroenterology. ACG clinical guidelines: diagnosis and management of celiac disease. Am J Gastroenterol. 2013;108(5):656-676. PMID: 23609613 pubmed.ncbi.nlm.nih.gov/23609613/.

Semrad CE. Approach to the patient with diarrhea and malabsorption. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 131.