Gluten-free diets are becoming increasingly popular, especially due to the growing awareness surrounding gluten intolerance.
In turn, this has fueled a rapid rise in the mainstream availability of gluten-free food options. In fact, the gluten-free food industry grossed over $15 billion in sales in 2016 (1Trusted Source).
The introduction of these products took what was once an extraordinarily difficult diet to follow and made it much simpler and considerably more accessible for the many people who need it.
This article reviews everything you need to know about gluten, including what it is, which foods contain it, and how it may affect those with gluten intolerance.
What is gluten?
Gluten is a family of storage proteins — formally known as prolamins — that are naturally found in certain cereal grains, such as wheat, barley, and rye (2Trusted Source).
Many different prolamins fall under the gluten umbrella, but they can be further classified based on the specific grains in which they’re found.
For instance, glutenins and gliadins are the prolamins in wheat, secalins are in rye, and hordeins are in barley (3Trusted Source).
Gluten offers a variety of functional culinary benefits and is responsible for the soft, chewy texture that is characteristic of many gluten-containing, grain-based foods (3Trusted Source).
When heated, gluten proteins form an elastic network that can stretch and trap gas, allowing for optimal leavening or rising and maintenance of moisture in breads, pasta, and other similar products (4Trusted Source).
Because of these unique physical properties, gluten is also frequently used as an additive to improve texture and promote moisture retention in a variety of processed foods.
Gluten-free diets are more common than ever, but gluten does not pose a health risk to the majority of the population. That said, people with celiac disease cannot tolerate gluten and must eliminate it from their diets to avoid harmful, adverse reactions.
Foods that contain gluten
Gluten may be found in a variety of whole and processed foods, including:
Grains: whole wheat, wheat bran, barley, rye, triticale, spelt, kamut, couscous, farro, semolina, bulgur, farina, einkorn, durum, wheat germ, cracked wheat, matzo, mir (a cross between wheat and rye)
Processed grain-based products: crackers, bread, breadcrumbs, pasta, seitan, wheat-containing soba noodles, some veggie burgers, cookies, pastries
Other foods and beverages: barley malt, malt vinegar, soy sauce, certain salad dressings, sauces or gravies thickened with flour, bouillon and some broths, certain spice blends, flavored chips, beer, certain kinds of wine
Because gluten is often used in food production as a thickener or stabilizer, it’s not always clear whether a particular food contains it.
What’s more, many commercial food operations share preparation equipment with gluten-containing foods. Thus, even if a food is inherently gluten-free, it could be contaminated with gluten during processing.
If you follow a strict gluten-free diet and are unsure about a particular food’s gluten status, check the package for a gluten-free label or contact the manufacturer prior to purchasing it.
Oats
When it comes to gluten-free diets, oats are a bit of a conundrum.
One of the main issues with oats is that they’re frequently transported and processed with equipment shared with wheat. This leads to widespread gluten contamination of oats, even if there isn’t mention of wheat or gluten on the product label (5Trusted Source).
Still, it’s easy to find oats that are certified and labeled gluten-free. Gluten-free oats are just regular oats that have been processed using equipment and facilities that are free of gluten contamination.
However, some experts argue that there’s no such thing as gluten-free oats — even if they’re labeled as such.
Oats contain a protein called avenin that is structurally very similar to the proteins in gluten.
Early research suggests that, in rare cases, a small percentage of people with existing gluten intolerance may experience a similar reaction to avenin as they do to gluten (5Trusted Source, 6Trusted Source).
That said, the vast majority of current evidence suggests that most people with gluten intolerance can tolerate gluten-free oats with no issues (4Trusted Source).
In fact, uncontaminated oats are often encouraged for gluten-free diets due to their rich supply of fiber and essential nutrients (5Trusted Source, 6Trusted Source).
Ultimately, more research is needed to better understand how avenin in oats affects digestion and immune function in people with gluten intolerance.
If you suspect that you may be intolerant to oats, consult your healthcare provider.
Foods to Avoid
Completely avoiding gluten can be challenging.
This is because it is found in many common ingredients that are added to foods.
These are the main sources of gluten in the diet:
Wheat-based foods like wheat bran, wheat flour, spelt, durum, kamut and semolina
Barley
Rye
Triticale
Malt
Brewer’s yeast
Below are some foods that may have ingredients containing gluten added to them:
Bread. All wheat-based bread.
Pasta. All wheat-based pasta.
Cereals. Unless labeled gluten-free.
Baked goods. Cakes, cookies, muffins, pizza, bread crumbs and pastries.
Snack foods. Candy, muesli bars, crackers, pre-packaged convenience foods, roasted nuts, flavored chips and popcorn, pretzels.
Sauces. Soy sauce, teriyaki sauce, hoisin sauce, marinades, salad dressings.
Beverages. Beer, flavored alcoholic beverages.
Other foods. Couscous, broth (unless labeled gluten-free).
The easiest way to avoid gluten is to eat unprocessed, single-ingredient foods. Otherwise, you should read the food labels of most foods you buy.
Oats are naturally gluten-free. However, they are often contaminated with gluten, as they might be processed in the same factory as wheat-based foods .