While gluten is found in grains like wheat, rye, and barley, it may also exist in many foods you wouldn't expect.
Gluten is a type of protein that acts as a binder, or "glue," to keep certain foods together.
It's found in several grains, including:
- Wheat (including durum, semolina, spelt, emmer or farro, Khorasan, einkorn, and freekeh)
- Triticale (a cross between wheat and rye)
While oats don't naturally contain gluten, many commercial varieties of oats and oat products are exposed to gluten during storage, transportation, or processing.
Traces of gluten may exist in many foods that you wouldn't expect, so if you're avoiding gluten for health reasons, be sure to look carefully at all ingredients listed and understand what they mean.
In addition to foods, some tablet and capsule medications contain gluten.
The National Library of Medicine offers two databases that let you look up ingredients in medications: Pillbox and DailyMed.
Still, not all medications may be listed, so talk to your doctor about whether any medications you take may contain gluten.
A gluten-free diet is one that eliminates all gluten.
This type of diet is primarily used to treat celiac disease, an autoimmune condition in which the body's immune system attacks the small intestine.
When people with celiac disease eat gluten, their small intestine becomes inflamed.
Over time, this inflammation can damage the lining of the small intestine, leading to malabsorption of nutrients.
Nutrient deficiencies can lead to health complications, such as osteoporosis, infertility, nerve damage, and seizures.
People with gluten sensitivity — a condition that is not celiac disease but causes gastrointestinal discomfort — also find relief when they eliminate gluten from their diet.
In recent years, there has been a growing trend to go gluten-free for various reasons unrelated to celiac disease or gluten sensitivity.
Some of these reasons include losing weight, boosting energy levels, treating autism, or feeling healthier.
But there isn't much research or evidence to support any relationship between a gluten-free diet and these outcomes.
Whether you want to avoid gluten for health or lifestyle reasons, it's important to talk with your doctor before eliminating gluten from your diet to avoid nutritional deficiencies.
Many gluten-containing foods also provide essential nutrients, such as vitamin B, folic acid, and fiber.
Knowing how to obtain these nutrients from other foods is important to staying healthy on a gluten-free diet.
The following foods are naturally gluten-free if they aren't processed and don't include any gluten-containing additives or preservatives:
- Beans, peas, and lentils
- Nuts and peanuts
- Meat, poultry, and fish
- Fruits and vegetables
- Dairy products
The following starches are gluten-free if they aren't mixed with gluten-containing grains:
- Gluten-free flours (rice, soy, corn, potato, bean, and others)
- Corn and cornmeal
- Hominy (corn)
- Potatoes and sweet potatoes
- Rice and wild rice
Editorial Sources and Fact-Checking
- What Is Gluten? Celiac Disease Foundation.
- Gluten-free diet; Mayo Clinic.
- Gluten in Medication; Celiac Disease Foundation.
- H. Strawbridge (2013). "Going gluten-free just because? Here's what you need to know." Harvard Health Publications.