Oats are a highly nutritious grain with many health benefits.

They’re a popular breakfast porridge and are also found in granola, muesli, and other foods and snacks.

However, you may wonder whether oats and oatmeal contain gluten.

This article explores whether you can include oats in a gluten-free diet.

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Gluten-free diets are very popular.

In fact, surveys reveal that as many as 15–30% of people in the United States try to avoid gluten for one reason or another.

Gluten is a family of proteins found in grains, such as wheat, rye, and barley. These proteins give bread and pasta their stretchy, chewy texture (1, 2, 3, 4).

Most people can eat gluten without any side effects, but these proteins can cause serious health problems for some individuals.

Gluten may cause digestive issues in certain populations because its unique amino acid structure may hinder the digestive enzymes in your gut (1, 2, 3, 4).

If you have celiac disease, your body launches an autoimmune response to gluten, damaging your intestinal lining (5).

If you’re intolerant to gluten, even a tiny amount is harmful, making a gluten-free diet the only way to avoid serious health issues (5, 6, 7, 8).

SUMMARY Gluten is a protein found in grains like wheat, barley, and rye. Most people can tolerate it, but it can harm some individuals.

Pure oats are gluten-free and safe for most people with gluten intolerance.

However, oats are often contaminated with gluten because they may be processed in the same facilities as gluten-containing grains like wheat, rye, and barley.

Studies show that most people with celiac disease or wheat allergy can eat 2–3.5 ounces (50–100 grams) of pure oats per day without adverse effects (9, 10, 11, 12, 13).

One 8-year study in 106 people with celiac disease revealed that half of them ate oats daily — and none experienced negative effects (10, 14).

Additionally, some countries recommend including oats in a gluten-free diet. A few studies note that people with celiac disease living in these countries had better intestinal healing than people in countries that did not (10, 15).

Pure, uncontaminated oats are also safe for people who have a wheat allergy.

SUMMARY Most people who are intolerant to gluten, including those with celiac disease, can safely eat pure oats.

Although oats themselves don't contain gluten, they’re often grown alongside other crops.

The same equipment is typically used to harvest crops in neighboring fields, which leads to cross-contamination if one of those crops contains gluten.

The sowing seed may also be impure, harboring a small amount of wheat, rye, or barley seeds.

Additionally, products made with oats are usually processed, prepared, and packaged in the same facilities as gluten-containing products.

Therefore, it’s unsurprising that studies analyzing regular oat products identified levels of gluten far exceeding the standard for gluten-free foods (16, 17, 18).

One study in 109 oat-containing products on the market in North America and Europe found that the products contained over 200 parts per million (ppm) of gluten, on average (16, 19).

Just 20 ppm of gluten may be enough to cause a reaction in someone with celiac disease (16).

This high risk of contamination means that it’s unsafe to include conventionally grown oats in a strict gluten-free diet.

Notably, a number of companies have begun to process oats with clean equipment and grow them in fields designated gluten-free. These oats can be marketed as gluten-free and must contain less than 20 ppm of gluten (20).

Still, even gluten-free labels may not be completely reliable. One study discovered that gluten levels exceeded safety limits in 5% of products labeled gluten-free.

However, 100% of the oat products passed the test, implying that labels certifying oats and oatmeal as gluten-free can be trusted in most cases (16, 21).

SUMMARY Oats are often contaminated with gluten during harvesting or processing, but many companies now sell uncontaminated products.

A very small number of people with celiac disease (and possibly other conditions) may still be unable to tolerate pure, uncontaminated oats.

Pure oats contain avenin, a protein that may cause problems because it has a similar amino-acid structure as gluten.

The majority of people who are sensitive to gluten do not react to avenin. They can eat pure, uncontaminated oats with no problems (22).

However, a tiny percentage of people with celiac disease may react to avenin. For these few people, even certified gluten-free oats may be unsafe (16, 23).

One study discovered that most people with celiac disease had the potential to react to avenin. However, only 8% of the participants had an actual response after eating a large amount of oats (24).

In those cases, the responses were small and did not cause clinical symptoms or relapse. Therefore, the researchers concluded that people with celiac disease could still eat up to 3.5 ounces (100 grams) of pure oats per day (24).

Additionally, two other small studies found that some people with celiac disease experienced a small immune response and more intestinal symptoms while eating oats than those on a traditional gluten-free diet (25, 26).

Despite these effects, none of the people in these studies experienced any intestinal damage from oats (25, 26).

SUMMARY Oats contain a protein called avenin. A small percentage of people with celiac disease react to avenin and may not be able to tolerate pure oats.

Gluten-free diets often have few food choices, especially in terms of grains and starchy foods.

Including oats and oatmeal can add much-needed variety.

What’s more, several studies show that following a gluten-free diet may result in an inadequate intake of fiber, B vitamins, folate, and minerals like iron, magnesium, selenium, manganese, and zinc (10, 27, 28, 29).

Oats happen to be a good source of all of these vitamins and minerals. They’re also a fantastic source of fiber.

Additionally, oats provide several impressive health benefits:

  • Heart health. Oats can help improve risk factors for heart disease by lowering LDL (bad) cholesterol and raising HDL (good) cholesterol (30).
  • Weight loss. Oats and oatmeal can aid weight loss by helping control appetite and increase fullness (31, 32, 33).
  • Diabetes control. Oats can help improve blood sugar control, blood fat levels, and insulin sensitivity in people with type 2 diabetes (34).
SUMMARY Oats are a good source of many nutrients that are lacking in a gluten-free diet. They can also add variety and provide several health benefits.

Oats are used in many gluten-free products, and oat flour is popular in gluten-free baking. Oatmeal is also a breakfast favorite for many people.

While there are many benefits to including oats in your gluten-free diet, it’s important to buy only products that are labeled or certified as gluten-free. This ensures that the oats are pure and uncontaminated.

In the United States and Europe, products certified gluten-free are required to have fewer than 20 ppm of gluten, an amount so low that foods with less than this amount are generally considered safe (20).

These days, it's easy to buy pure oats in many grocery stores and online.

The decision to include oats should be made on an individual basis.

Since it's not possible to know whether you’ll react to avenin, you might want to consult your medical practitioner before adding oats to a gluten-free diet.

However, the vast majority of people can safely enjoy oats and all of the delicious foods made with them.