What Is Gluten? An In-Depth Look At This Family Of Proteins

What Is Gluten? An In-Depth Look At This Family Of Proteins

Gluten is a family of proteins that is responsible for the elasticity of dough. While many are familiar with popular gluten-containing foods such as bread and pasta, the exact composition of gluten and how it works aren’t usually as well known. Read below to find out what gluten really is.

According to a 2013 survey over 30% of the American population is actively trying to remove or limit gluten in their diet. However, only 1 out of 100 people have celiac disease.

As popular as the gluten free diet has become many people still don’t truly understand what gluten is or why they should avoid it.

In this article, we’ll be covering the topic of gluten in-depth to help you learn what it is, where it comes from, and how it affects different people.

What Exactly is Gluten, Anyway?

The simplest explanation of gluten is that it is a type of protein found in certain grains including wheat, barley, and rye. When it comes to wheat, in particular, there are two primary types of protein that fall under the gluten category – gliadins and glutenins. These proteins are what gives bread the ability to rise and lends it that characteristic “doughy” texture we all know well.

While wheat is the main culprit when it comes to gluten, there are two other grains to watch out for – rye and barley. Rye is a cereal plant similar to wheat that is commonly grown as an edible grain, a cover crop (grown for the protection and enrichment of the soil), and a forage crop (grown specifically to be grazed by livestock). It is also a large component of the fermentation process through which whiskey is made. Barley is a cereal grain widely used for brewing and, like rye, stock feed. Both rye and barley are grasses like wheat and all three are closely related on a structural level.

Although the glutens found in wheat are different from those found in barley and rye, they all have a similar effect on the body for people who have celiac disease. Celiac disease is sometimes thought of as an extreme version of a wheat allergy but it is actually an autoimmune disease. When a person with celiac disease consumes gluten, their immune system recognizes the proteins as foreign invaders and releases antibodies to neutralize the threat. Unfortunately, this immune response also ends up damaging the lining of the small intestine which leads to celiac-related symptoms. 

Are There Different Types of Gluten?

We’ve already mentioned that there are two primary types of gluten found in wheat, but what about glutens found in rye and barley? The term “gluten” applies to a wide variety of specific proteins found in each of the three so-called “gluten grains.”

The two main types of gluten found in wheat are gliadins and glutenins. Within the gliadin class of proteins, there are four different epitopes (the part of gluten that is recognized by the immune system):

  • Alpha-gliadin
  • Beta-gliadin
  • Gamma-gliadin
  • Omega-gliadin

When you consume wheat-based food products, enzymes in the digestive tract known as tissue transglutaminase (tTG) work to break down the wheat component of the food. In the process, other proteins like deamidated gliadin and gluteomorphins are formed. Celiac disease is a reaction to alpha-gliadin and a particular form of tTG, but the human body can develop a negative reaction to any of the various types of gluten protein and transglutaminases.

Still, the question remains – are there different types of gluten in different grains?

The type of gluten found in rye is called secalin and the gluten found in barley is called hordein. What you need to know is that both of these glutens contain the protein fraction gliadin. So, essentially, negative reactions to protein from different gluten grains are all caused by the same type of protein.

Do People React Differently to Different Glutens?

Celiac disease is a very confusing condition because the range of symptoms is so large and because the disease affects each individual differently. Many people with celiac disease go undiagnosed for years because either their symptoms are too mild to be much of a bother or because they are confused with the symptoms of another disease. Misdiagnosis and underdiagnosis is an often occurrence. In fact, a 2005 survey found a lack of physician awareness of celiac symptoms and testing may contribute to the underdiagnosis of celiac disease.

Trouble can occur if you have a different reaction to one type of gluten than you have to another type. This raises the question – do people react differently to different types of gluten and, if so, why?

As we already mentioned in the previous section, glutens found in wheat, rye, and barley are known by different names but they all contain the protein fraction gliadin. So, if you have celiac disease, you can expect to experience a negative reaction when consuming any of these three gluten grains. But the specifics of your reaction (and its severity) may vary depending which grain you consume.

The gliadin protein is particularly problematic for celiac individuals because it cannot be fully digested by the stomach or by enzymes in the digestive tract. So, when the protein enters the small intestine it has the potential to do some serious damage. There may be a difference, however, in how gliadin from different grains is broken down.

You may be interested to learn that storage proteins in rye, while they still contain gliadin, do not form gluten when they are mixed with water and kneaded into dough. That gluten helps to break down the gliadin just a little bit more during the digestive process which means that some people may have a lesser reaction to rye than to wheat.

So, what about the gluten found in barley?

The specific type of gluten found in barley is called hordein and it is found in the seeds of the plant (the part you know of as the grain). Because the seeds of the plant are the part most commonly used, most barley-containing products are going to produce a reaction in celiac individuals. There is some debate whether foods made only with barley grass contain gluten, but it is largely up to the individual whether they have a reaction or not.

What Foods Should You Avoid on the Gluten Free Diet?

If you have celiac disease, the only medical treatment available is to switch to a gluten free diet. Individuals with gluten sensitivity, gluten allergies, and gluten intolerance will also benefit from making this dietary change.

But where exactly do you find gluten in foods, and which foods should you avoid?

The main foods you need to avoid on the gluten free diet are anything that contains wheat, barley, or rye. Keep in mind, however, that there are different variations of these grains. Here is a list of gluten-containing grains to avoid:

  • Wheat
  • Spelt
  • Kamut
  • Triticale
  • Durum
  • Einkorn
  • Farina
  • Semolina
  • Couscous
  • Barley
  • Rye

The best way to tell whether a food product contains gluten is to read the food label. Start by checking the allergen warning – if the product lists wheat as an allergen, it’s a safe bet that it probably also contains gluten.

After checking the allergen warning, take a look at the ingredients list to check for sources of wheat, barley, or rye. Remember to look for any of the different forms of gluten grains from the list above and do another check for buzz words that suggest gluten. Malt is a great example of a hidden source of gluten that comes from barley (think malt vinegar or malt liquor). If you don’t see any gluten-containing ingredients on the list, the product may be safe to eat. The only way to really guarantee safety, however, is to look for the “gluten free” label.

Wondering which foods pose the highest risk? Here is a quick list of some of the foods which are most likely to contain gluten from wheat, barley, or rye:

  • Cereal
  • Cakes
  • Cookies
  • Crackers
  • Pretzels
  • Pasta
  • Pizza crust
  • Breaded meat
  • Processed cheese
  • Fried foods
  • Baking mixes
  • Cheesecake filling
  • Granola
  • Protein bars
  • Multigrain chips
  • Soy sauce
  • Imitation crab
  • Artificial flavors
  • Licorice and candy
  • Creamy soups
  • Salad dressings
  • Seasonings
  • Beer
  • Malt liquor

Whether you’re going gluten free by choice or by necessity, it will take some time to learn how to identify sources of gluten in common foods. The key is to be extremely careful when purchasing packaged foods and to largely structure your diet around naturally gluten free whole foods like meat, fruits, veggies, nuts, and seeds.