What Are Gluten Grains?

It's getting pretty common these days for people to report that they're avoiding the three gluten grains: wheat, barley, and rye. These three grains contain the gluten protein, which causes celiac disease and may cause non-celiac gluten sensitivity.

But unfortunately, not everyone—even some who have been diagnosed with celiac or gluten sensitivity—has a clear idea of what these "gluten grains" actually are. There's a lot of misinformation out there, with some people (mistakenly) saying that grains like corn and rice should be counted among gluten grains (they do not contain the form of gluten that makes people react).

To help combat that misinformation, here's a cheat sheet for determining which are the true gluten grains you need to avoid if you're following the gluten-free diet. I've also included short explanations of where each gluten grain is most likely to be found.

Wheat: the Primary Gluten Grain

This one is easy: the vast majority of people avoiding gluten know that they need to steer clear of wheat.

In fact, wheat is by a large margin the most common of the three gluten grains—in fact, wheat is the leading source of vegetable protein for humans worldwide, and comes in second only to corn in terms of annual worldwide production.

You'll find wheat in conventional bread, pasta, cookies, cakes, and crackers. But you'll also find wheat in processed foods like soy sauce, canned soups, certain candy, and even ice cream. These wheat sources certainly can make it a challenge to eat gluten-free. 

Wheat also can go by other names, including spelt, Einkorn and farro. Nonetheless, all of these are still gluten grains, and you'll need to avoid them if you're eating gluten-free.

Barley: Not Just in Beer

The second most common gluten grain is barley, a close relative to wheat. Barley first was cultivated in western Asia and northeast Africa more than 10,000 years ago and spread from there into Europe and the rest of Asia.

These days, barley-based breads, soups, porridges, and stews are popular in Middle Eastern cuisine and in northern Europe, particularly in the northern British Isles. And, most beer (with the exception of gluten-free beer) contains barley, as do certain types of distilled alcohol.

You also should look for barley as an ingredient in canned soups (pearled barley is a popular ingredient) and in anything malted (malt is almost always made from barley).

Rye: Unusual but Not Unheard Of

Rye, the third gluten grain, is pretty simple to avoid: you generally find it only in certain breads (bakers in Germany and Eastern Europe use more rye than others) and in crackers. It's generally called out on food labels as "rye" since it's an expensive ingredient and the food manufacturers want to disclose it. Rye isn't normally used as an ingredient in other processed foods.

Of course, the exception to this rule is distilled alcoholic beverages. Rye whiskey is made from rye grain, as are some vodkas. Some people with celiac disease and gluten sensitivity react to distilled alcoholic beverages derived from gluten grains, while others can drink them without a problem.

Worth noting: the ryegrass grown on lawns isn't from the same family as rye the gluten grain, so you won't get glutened mowing your ryegrass lawn.

What About Oats? Corn? Rice?

None of these are considered "gluten grains." All grains do contain some form of gluten (which is a generic name for protein in the grain), but only wheat, barley, and rye contain the type of gluten that's a problem in celiac disease and non-celiac gluten sensitivity.

Oats are a special case. Although oats are not a gluten grain, you should be aware that some people who react to gluten grains also react to oats.

In addition, there's some evidence that people with celiac disease may react to corn, which also is not a gluten grain. However, most medical studies show that people with celiac disease and non-celiac gluten sensitivity can consume corn without issue.

A Word From Verywell

There's a considerable amount of disinformation out there on how to best eat gluten-free. In fact, it's not unusual to have doctors and others who seem like authorities on the subject tell you that you have to avoid corn, rice, and other grains in addition to avoiding wheat, barley, and rye.

However, the truth is that most people with celiac disease and non-celiac gluten sensitivity can eat other grains, including corn. If you're confused about what you can eat, or if you believe you're having a reaction to something other than gluten grains, talk to your doctor about additional testing.