What Is Gluten, Which Foods Include It, and How to Tell Celiac Disease vs. Sensitivity

People with certain medical conditions should avoid gluten

Gluten is a protein found in certain grains, including wheat, rye, and barley. There is nothing inherently bad or unhealthy about gluten. However, some people with certain medical conditions, such as celiac disease or non-celiac-related gluten sensitivity, should avoid it.

This article will cover everything you need to know about foods with gluten, who may need to go gluten-free, as well as gluten-free diet options. 

Person kneading dough

Emilija Manevska / Getty Images

What Is Gluten?

Gluten is a naturally occurring protein found in some grains, including barley, rye, wheat, and triticale (a cross between wheat and rye) and products made from them.

In foods such as bread and baked goods made from these grains, gluten helps bind the product together to provide texture and structure, so they can maintain their shape. Gluten also adds protein and flavor to foods.

Most people are able to safely consume and tolerate gluten-containing foods. However, some people with certain medical conditions, such as celiac disease or gluten-related sensitivity, react to gluten and should avoid it.

What Does a Gluten-Free Label Mean?

In the United States, labeling a food “gluten-free” is a voluntary claim that manufacturers may choose to use, according to the Food and Drug Administration (FDA). Any foods that carry the label “gluten-free,” “no gluten,” “free of gluten,” or “without gluten” must contain less than 20 parts per million (ppm) of gluten.

In addition to containing no more than 20 ppm of gluten, foods labeled “gluten-free” must not also contain any type of wheat, barley, or rye or have not been processed to remove gluten below 20 ppm.

This FDA labeling rule applies to all foods and beverages except for meat, poultry, and certain egg products, which are regulated by the Department of Agriculture, as well as most alcoholic beverages, which are regulated by the Alcohol and Tobacco Tax and Trade Bureau (TTB), Department of the Treasury.

Here are some tips to follow when shopping for gluten-free foods

  • Look for the words “gluten-free” on the label.
  • Avoid any ingredients containing wheat, rye, barley, or triticale.
  • Avoid products that do not say “gluten-free” and that do say “may contain” or “made on shared equipment with” wheat or gluten.
  • Contact the manufacturer if you are unsure if a food or beverage contains gluten.

What Foods Contain Gluten?

People with celiac disease or who have a gluten-related sensitivity should avoid all food products with barley, rye, or wheat in the ingredients list, or that state on the label that the product was manufactured in the presence of wheat, gluten, or gluten-containing ingredients. 

Food products that often contain gluten include:

  • Beer and ale (gluten-free beers and ales are available)
  • Breads
  • Breaded fried foods, such as breaded fish, chicken, or vegetables
  • Brewer’s yeast
  • Cakes
  • Candies
  • Cereals (both hot and cold)
  • Cookies
  • Crackers
  • Malt
  • Meatball or meatloaf (if flour or bread crumbs are used as a binder)
  • Pasta
  • Pastries
  • Pies
  • Pizza
  • Pretzels
  • Roux
  • Salad dressings
  • Sauces
  • Seitan (high-protein meat substitute)
  • Soups (most often cream based)
  • Soy sauce (wheat-free tamari is an alternative)

The Controversy Over Oats

Oats do not contain gluten. However, they are often grown in fields with grains that contain gluten or are processed in gluten-containing facilities or transported with gluten-containing foods. This sets up the possibility of cross-contamination (when a gluten-free product comes into contact with something that is not gluten-free).

If you choose to eat oats, be sure to only use oat products that are labeled as gluten-free. This means the manufacturer has taken measures to prevent gluten-containing foods from cross-contaminating the oats.

Additionally, oats contain a protein called avenin that is similar to gluten. Some people with celiac disease also have an immune reaction to avenin and thus choose to avoid oats altogether.

Medical Conditions That Require a Gluten-Free Diet

Some people with certain medical conditions must avoid gluten and gluten-containing foods and beverages. This is because their body reacts to the gluten and causes an immune reaction, digestive upset, or other symptoms.

Celiac Disease

Celiac disease is a genetic, autoimmune condition in which the immune system mistakenly attacks the body when gluten is consumed. The immune response to gluten damages the villi in the small intestine (small fingerlike projections that line the wall of the small intestine). This results in decreased or poor nutrient absorption.

It is estimated that 1 in 100 people worldwide are affected by celiac disease. However, only about 30% are accurately diagnosed.

Currently, the only treatment for celiac disease is lifelong adherence to a gluten-free diet. Even consuming small amounts of gluten, such as bread crumbs from a cutting board or toaster, can trigger an immune response and cause damage to the small intestine.

Non-Celiac Gluten Sensitivity 

Some people who do not test positive for celiac disease or a wheat allergy may still experience symptoms similar to celiac disease, which resolve when gluten is removed from the diet. This is called non-celiac gluten sensitivity (NCGS) or non-celiac wheat sensitivity (NCWS) or is sometimes referred to as gluten intolerance.

It was previously thought that people with NCGS/NCWS only experience symptoms, with no damage to the small intestine. However, some research confirms that wheat exposure in these people does trigger an immune reaction and resulting damage to the intestines.

Research has not concluded that gluten is responsible for triggering the immune reaction in NCGS/NCWS. Other possible triggers include amylase-trypsin inhibitors (ATIs) and fructans, which are found in wheat and other gluten-containing foods. Gluten might not be the direct cause of the NCGS/NCWS.

Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder that causes abdominal pain, bloating, distension, excessive flatulence, constipation, and/or diarrhea. The exact cause of IBS is unknown, though it's thought that a combination of factors may lead to symptoms, including eating certain foods.

Gluten itself hasn't been identified as a cause of IBS, though some people with IBS may be sensitive to gluten.

Some people with IBS find that high-FODMAP foods (foods high in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) tend to bring on symptoms. These are carbohydrates such as fructose, lactose, and sugar alcohols that are poorly absorbed in the small intestine.

Some high-FODMAP foods also contain gluten. Consequently, people on a low-FODMAP diet don't often consume a lot of gluten, though this type of eating plan is not a strict gluten-free diet.

Wheat Allergy

A true wheat allergy develops when your immune system overreacts and produces antibodies to proteins found in wheat. Symptoms include hives or skin rash, stomach upset, stuffy or runny nose, sneezing, headaches, asthma, or, less commonly, anaphylaxis (a severe, life-threatening allergic reaction that can hinder breathing and cause the body to go into shock).

People with a wheat allergy need to avoid wheat and all wheat-derived or crossbred grains. Because gluten-free foods do not contain wheat, people with a wheat allergy can eat gluten-free foods. However, not all gluten-containing foods need to be avoided. Those made with rye or barley can be eaten.

If you have a wheat allergy, even if a food is labeled gluten-free, always read the complete ingredients list to ensure no wheat is in a food or beverage before consuming it.

Celiac Disease vs. Gluten Sensitivity or Intolerance

If you suspect your body reacts to gluten, meeting with a healthcare provider, such as a gastroenterologist, is important. They can run tests, including those to rule out celiac disease. If you do not receive a diagnosis of celiac disease, you may still be intolerant or sensitive to gluten.

Gluten intolerance or sensitivity differs from celiac disease, though the conditions may have some overlap. Both can cause pain and discomfort, but celiac disease tends to have more serious or severe symptoms and complications.

Celiac disease is a genetic autoimmune disorder that causes inflammation and damage to the small intestine. It has possible long-term complications if left untreated. Symptoms of celiac disease include:

Non-celiac gluten sensitivity or intolerance is not thought to be genetic and usually causes less severe symptoms than celiac disease. It is a diagnosis considered when celiac disease and wheat allergy are ruled out while a person is on a gluten-containing diet. It may be confirmed if the person's symptoms resolve on a gluten-free diet and return when given a gluten challenge.

Common Gluten Intolerance Symptoms

Common symptoms of gluten intolerance or sensitivity include:

  • Abdominal pain
  • Bloating
  • Change in bowel patterns (such as diarrhea or constipation)
  • Headache
  • Fatigue
  • Joint and muscle pain
  • Skin rash
  • Brain fog

What to Eat on a Gluten-Free Diet

Even though the focus tends to be on what gluten-contain foods need to be avoided, it’s equally important to know what foods are allowed on a gluten-free diet. Below are foods that are gluten-free and safe on a gluten-free diet.

Grains

The grain food group is often the trickiest to navigate when it comes to avoiding gluten. However, there are many gluten-free grains that you can eat on a gluten-free diet. These include:

  • Amaranth
  • Buckwheat
  • Corn
  • Millet
  • Gluten-free oats
  • Quinoa
  • Rice
  • Sorghum
  • Teff

In addition to the above grains, when baking at home, there are several wheat-flour substitutes (most of which are grain-free), such as tapioca flour, potato flour, almond flour, coconut flour, or bean flour.

Fruits

All fresh fruits are naturally gluten-free, such as:

  • Apples
  • Bananas
  • Berries, such as raspberries, blueberries, and strawberries
  • Citrus fruits, such as oranges, lemons, and grapefruit
  • Grapes
  • Melons
  • Pears
  • Stone fruits, such as apricots, peaches, and plums

Be cautious with dried fruits, sauces, syrups, jams, jellies, pastries, or other baked goods made with fruit, as they may not be gluten-free. Always read the ingredients list to verify there is no gluten in the product before consuming.

Vegetables

All fresh vegetables are naturally gluten-free, including:

  • Asparagus
  • Beans
  • Carrots
  • Cruciferous vegetables, such as broccoli and cauliflower
  • Leafy greens, such as spinach, kale, and romaine lettuce
  • Peas
  • Potatoes
  • Squash (all varieties), such as zucchini, yellow squash, pumpkin, butternut, and spaghetti squash

Beware of foods containing vegetables along with foods that may not be gluten-free, such as soups, casseroles, savory pastries, or frozen or canned vegetables with added flavorings or sauces.

Dairy

Most dairy products are naturally gluten-free. These include milk, cheese, yogurt, cottage cheese, butter, ghee, cream, and sour cream. 

Check the labels of dairy products with added flavorings or mix-ins, such as flavored or malted milk, flavored yogurt, and ice creams. Additionally, beware of processed cheese products, such as cheese spreads or sauces, or cream-based soups or sauces, as they may be thickened with a gluten-containing product. 

Protein Foods

Most fresh plant and animal proteins are naturally gluten-free. These include:

  • Eggs
  • Legumes, such as beans, peas, lentils, peanuts
  • Nuts, such as almonds, walnuts, pecans, and pistachios
  • Poultry, such as chicken and turkey
  • Red meat, such as beef, pork, and lamb
  • Seafood, such as fish, shellfish, and scallops
  • Seeds, such as flax, chia, and sunflower seeds
  • Soy products (plain varieties), such as tofu, tempeh, and edamame

Use caution and check the labels of processed meats such as lunch or deli meats, hot dogs, salami, pepperoni, sausage, and bacon. Other protein sources that may contain gluten include mixed egg dishes, breaded meat, poultry, or fish, meatloaf or meatballs, or those that have added sauces, flavorings, or marinades.

Fats

All fats and oils are naturally gluten-free, including:

  • Avocados and avocado oil
  • Butter
  • Coconut oil
  • Ghee
  • Olives and olive oil
  • Vegetable and seeds oils, such as canola and sunflower oil

Beware of cooking sprays and oils containing added flavorings, seasonings, or spices, as they might have a gluten-containing ingredient.

Beverages

While some beverages contain gluten, such as wheat-, rye- or barley-based beers and ales, there are many gluten-free beverages allowed on a gluten-free diet. These include:

  • Some alcoholic beverages, such as wine, hard ciders, and beer made from gluten-free grains
  • Coffee
  • Energy drinks
  • 100% fruit juice
  • Lemonade
  • Tea
  • Soda
  • Sports drinks
  • Water

Beware of any beverage with added flavorings or mix-ins, such as flavored coffee beverages and smoothies,  non-distilled liquors, malt beverages, and wine coolers.

Don’t Cut Gluten From Your Diet Until Talking With a Healthcare Provider

If you think you have an issue with gluten, speak with a healthcare provider. Eliminating gluten from your diet can result in inaccurate or invalid test results. In order to properly test for celiac disease and receive an accurate diagnosis, you must currently be consuming gluten in your diet.

After you have been fully tested, a healthcare provider may then advise you to commence a gluten-free diet, depending on your diagnosis.

Summary

Gluten is a protein found in certain grain products, including wheat grains, rye, and barley and foods and beverages made with or derived from those grains. Most people are able to safely consume gluten without any adverse health effects.

However, some people with certain medical conditions, such as celiac disease or non-celiac gluten sensitivity, need to avoid gluten-containing foods and beverages. Other conditions, such as irritable bowel syndrome (IBS) or wheat allergy, may need to eliminate some gluten-containing grains and foods from their diet but generally do not need to completely avoid all sources of gluten. 

Consuming gluten with celiac disease results in inflammation and damage to the villi of the small intestine. Symptoms may include abdominal pain, bloating, foul-smelling stool, weight loss, anemia, or failure to thrive. Common symptoms of gluten sensitivity or intolerance include abdominal pain, bloating, and a change in bowel patterns. 

Labeling products “gluten-free” is voluntary, but if a food label displays a “gluten-free” label, it must contain less than 20 parts per million (ppm) of gluten. Gluten-free foods include all fresh fruits, vegetables, animal and plant proteins, fats and oils, most plain (unflavored) dairy products, and whole grains outside of wheat, rye, and barley. 

If you suspect you have issues related to gluten, schedule an appointment with a healthcare provider. Do not stop consuming gluten prior to your appointment, as this may yield inaccurate results when testing for celiac disease.

19 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Celiac Disease Foundation. What is gluten?

  2. Food and Drug Administration. Gluten and food labeling.

  3. Celiac Disease Foundation. Sources of gluten.

  4. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & causes of celiac disease.

  5. Celiac Disease Foundation. What is celiac disease?

  6. MedlinePlus. Gluten sensitivity.

  7. Uhde M, Ajamian M, Caio G, et al. Intestinal cell damage and systemic immune activation in individuals reporting sensitivity to wheat in the absence of coeliac disease. Gut. 2016;65(12):1930-1937. doi:10.1136/gutjnl-2016-311964

  8. Al-Toma A, Volta U, Auricchio R, et al. European society for the study of coeliac disease (ESsCD) guideline for coeliac disease and other gluten-related disorders. United European Gastroenterol J. 2019;7(5):583-613. doi:10.1177/2050640619844125

  9. Roszkowska A, Pawlicka M, Mroczek A, Bałabuszek K, Nieradko-Iwanicka B. Non-celiac gluten sensitivity: a review. Medicina (Kaunas). 2019;55(6):222. doi:10.3390/medicina55060222

  10. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & causes of irritable bowel syndrome.

  11. Volta U, Pinto-Sanchez MI, Boschetti E, Caio G, De Giorgio R, Verdu EF. Dietary triggers in irritable bowel syndrome: is there a role for gluten?. J Neurogastroenterol Motil. 2016;22(4):547-557. doi:10.5056/jnm16069

  12. van Lanen AS, de Bree A, Greyling A. Efficacy of a low-FODMAP diet in adult irritable bowel syndrome: a systematic review and meta-analysis. Eur J Nutr. 2021;60(6):3505-3522. doi:10.1007/s00394-020-02473-0

  13. American College of Allergy, Asthma, & Immunology. Wheat.

  14. Celiac Disease Foundation. Non-celiac gluten/wheat sensitivity.

  15. Celiac Disease Foundation. Symptoms of celiac disease.

  16. Catassi C. Gluten sensitivity. Ann Nutr Metab. 2015;67 Suppl 2:16-26. doi:10.1159/000440990

  17. Celiac Disease Foundation. Gluten-free foods.

  18. Whole Grains Council. Gluten free whole grains.

  19. Celiac Disease Foundation. Testing.

By Brittany Poulson, MDA, RDN, CD, CDCES
Brittany Poulson, MDA, RDN, CDCES, is a registered dietitian and certified diabetes care and education specialist.