Gluten is a complex mixture of hundreds of related but distinct proteins that accounts for as much as 80% of the total protein content of a grain of wheat. Once mixed with a liquid, these proteins become elastic and stretchy, making yeast bread irresistible even to people who find other foods containing wheat, rye, and barley off-limits. As for the rest of us, depending on which food tribe you identify with, gluten is either a friend or a foe. A small but growing number of people say that gluten makes them feel sluggish, bloated, and just generally unwell. That has driven a market for gluten-free foods that has grown nearly thirty percent in the past seven years.

Based on that, you might think that most people would be better off avoiding gluten. Yet the overwhelming majority of people have no problem with gluten at all and can – nay, should – eat it in large enough quantities to meet their daily iron and B-vitamin requirements. In fact, there is growing evidence that avoiding foods containing gluten could even make people more vulnerable to other health problems. So, rather than avoid gluten or swear that living without gluten wouldn’t be worth it at all, it’s worth understanding what this much-maligned protein mix really is. This guide will help you stand up for or against gluten and ensure that you’re not swallowing misconceptions. Whether you think gluten is a friend or a foe will mostly depend on how you answer the question that began this guide.

1. Understanding Gluten

Gluten can be confusing. There are so many mixed messages about gluten, though, that these conversations feel more like phone tags than an informed discussion. That said, gluten is essential to understand because some people in the population need to avoid it in order to be healthy. We can improve our relationship with this mixture of proteins by understanding what it is, why it is used, and who should avoid it. Gluten may not be suitable for everyone, but fear should not guide our decisions. We need better information to understand when it can bolster the taste and texture of our food. (Demirkesen and Ozkaya2022)

Gluten is a composite of two proteins naturally found in wheat called glutenin and gliadin. It is created when molecules in the wheat flour come into contact with water. Yet gluten does not like water, and it repels water molecules, forming an interconnected web of protein. This network can trap the gas produced by chemical leavening agents or yeast as they ferment, leading to the airy crumb that we love in baked goods. Gluten also provides the structure in dough. Because of gluten, dough can stretch to contain gas bubbles without bursting while holding the shape of the loaf as it rises. This is also why gluten provides the chew in a pizza crust and the heft for a great baguette. Even though wheat gluten contains several hundred proteins, only a small number of them cause adverse reactions. Most notably, the majority of people with a gluten-related disorder are unable to digest gliadin, so we will focus on this specific protein in the discussion that follows. Only a few types of grains contain gliadin-laden gluten, making it possible for pasta, bread, and pastries to be safely enjoyed by those with a gluten-related disorder by avoiding any of these grains.

1.1. What is Gluten?

Gluten is the name given to a protein complex found in wheat, as well as its other forms: triticale, and spelt, kamut, and other ‘ancient’ wheat species. The term ‘gluten’ literally means ‘glue’ and refers to this protein’s ‘stickiness’ or ability to form a cohesive mass inside dough. This characteristic manifests as small, generally insoluble particles that embed themselves in a primarily starch-based matrix to add elasticity and chewiness. Gluten is composed of two primary proteins: gliadin, which gives dough its final ‘curvature’, maintaining its shape as it rises during baking; and glutenin, which is responsible for the majority of the sticky, tough behavior characteristic of gluten. Together, gliadin and glutenin create a dough that can stretch into thin sheets without breaking, and since the earliest days of leavened bread more than 4,000 years ago, it is gluten that has provided the crumb texture critical for evaluating the ‘quality’ of bread and other baked goods. (Cappelli et al., 2020)

As members of the family of proteins called ‘prolamins’, gluten and gliadin are similar to the prolamin proteins found in other grains, such as ‘zein’ in corn and the ‘avenins’ of oats. And those who react poorly to gluten will no doubt not harp on the differences. Nevertheless, there are indeed differences: most notably the fact that while prolamins in other grains are quite similar to people in their native form, the prolamin in wheat is not. This is unlikely to make much meaningful difference in most people’s lives since the majority of prolamin peptides do not survive the digestive process intact to make this point worth worrying over, but it is an interesting scientific twist on what sets gliadin and gluten apart from other prolamins. Regardless of what it is, and in what other grains it may or may not occur, gluten is an essential foundation to the way we eat and live.

1.2. How Gluten Works in Food

How gluten functions in the context of food preparation is relevant given the persistence and wide range of gluten-containing foods in the Western diet. Gluten forms not directly from water and flour, but rather during mixing: flour incorporates some water to form a stiff mass, which allows the glutenins to meet and bind to one another. As mixing continues, the glutenins are drawn into progressively thinner and thinner sheets, with wetter dough having more sheet-like interfaces and a corresponding increase in gluten strength. The final product of mixing and kneading is a network of proteins, both coils and sheets, which work together to provide structure and support for the product. As a result of the increased mixing and kneading time, more interactions form at sheet surfaces, resulting in a higher quality network with increased retention of gas and water during baking.

This network-scaffolding property of gluten is the basis of many gluten-related complaints. Some grains – especially wheat, but also barley and many ancient wheat varieties – naturally contain a large amount of protein, and particularly a plethora of gluten. Most flours milled today from this grain contain enough gluten proteins to bind water and trap gas during baking, resulting in a spongy texture that depends, at least at the micro-structural level, on gluten. In contrast, most gluten-free formulas aim to substitute the benefits of gluten mechanisms, like elasticity and gas retention, with alternative ingredients. Thus, based on this understanding of gluten’s role in the culinary world, bakers seeking to modify their gluten consumption can strategically select a flour composition most consistent with their desired finished product.

2. Gluten-Related Disorders

Although celiac disease is the most widely recognized gluten-related condition, it is not the only one. One of the rarest is wheat allergy, in which the body’s immune response to the protein in wheat, including gluten, results in allergic symptoms such as hives, difficulty breathing, anaphylaxis, and other food allergy-related symptoms. The real trickiness of gluten is associated with two progressively more common complicated conditions: celiac disease and non-celiac gluten sensitivity, which should be differentiated and confirmed with appropriate diagnostic tests.

Celiac disease can develop in severe cases from the malabsorption of nutrients, particularly neurological and skin complications, and can lead to mortality. Because of the autoimmune component, diagnosed persons need to adhere to a strict gluten-free diet for life. Celiac disease is, however, not common. It is found in 1% of the population. Having a list of disorders related to the ingestion of dietary gluten, the most severe of these is celiac disease in only about 1%. Nonceliac gluten sensitivity is being increasingly recognized and is still, from certain standpoints, not completely understood. Current estimates of prevalence range from 0.5% to 10%, and patients may suffer from a gluten-induced symptom that has a generally quick onset and resolves after gluten is withdrawn. Most people can consume gluten without developing any related symptoms or bodily injury.

2.1. Celiac Disease

Celiac disease is a serious autoimmune disease that occurs in genetically predisposed people where the ingestion of gluten leads to damage in the small intestine. Approximately one in 100 individuals worldwide have the genetic factors linked to celiac disease, which are two human leukocyte antigen genes, or HLA genes, DQ2 or DQ8, although not everyone with these gene types will develop celiac disease. Those with a first-degree relative, such as a parent, sibling, or child, who has been diagnosed with celiac disease may have a 1 in 10 risk of developing celiac disease as well. The symptoms of celiac disease are not limited to gastrointestinal issues such as alternating bowel movements or floating, smelly stools stemming from malabsorption. Symptoms can also affect the joints, skin, brain, and much more, including miscarriages.

Those experiencing symptoms should seek out a healthcare provider. A blood test and an intestinal biopsy can be utilized to determine the body’s reaction to gluten ingestion and must be done before a person can proceed on the gluten-free diet that is necessary to manage and heal celiac disease damage. The only treatment for celiac disease is to follow a strict gluten-free diet, which does mean shutting off the ability in the future to return to eating gluten, after biopsy testing and blood work can confirm complete healing and recovery. Those with an official celiac disease diagnosis may also need guidance on how to avoid accidental gluten ingestion given regulations and cross-contact issues and will need a lifelong muscular and social support system. Although celiac disease can be diagnosed, such cases as NCGS or wheat allergy are not uncommon. Family health histories are important because those with a relative who has celiac disease are ten times more likely to develop celiac disease. With gluten-free items readily available, there is confidence that the public needs to learn about celiac disease and start asking questions from their medical providers when they think that they may have celiac disease.

2.2. Non-Celiac Gluten Sensitivity

Many individuals report adverse reactions upon consuming gluten, despite not having celiac disease. Research supports a distinct profile of symptoms experienced by non-celiac gluten sensitivity (NCGS) individuals, with gastrointestinal discomfort and systemic symptoms such as fatigue being most common. However, the underlying cause of these symptoms remains elusive. NCGS refers to adverse reactions to gluten ingestion absent of the autoimmune response to gluten that characterizes celiac disease. For unknown reasons, the pathological processes of NCGS have to date evaded scientific scrutiny, leaving this area controversial. Immunological and extraintestinal manifestations, primarily described after wheat consumption, are part of the symptoms characterizing NCGS. Historically, the inclusion of these atypical symptom manifestations in gluten-related disorder classification systems has been surrounded by controversy. These disorders were only recently collectively termed ‘wheat-associated disorders.’ NCGS is also a controversial topic in the field because currently there are no specific biomarkers or diagnostic tests for it. The diagnosis relies mainly on the identification of symptoms to gluten that are rapidly relieved by gluten withdrawal and that recur upon gluten challenge after a period of exclusion tailored according to the lines of those of each specific gluten-related disease. However, the exact pathophysiology of NCGS is not completely clear yet. NCGS may utilize multiple (possibly overlapping) pathogenetic pathways and, in any single individual, a particular pathway may have different gears that may play a more relevant pathophysiologic role. Taken together, these observations suggest that the characterization of NCGS is more complex than originally thought, and its understanding will require a more tailored and multidisciplinary diagnostic strategy ultimately relying on patient-reported outcomes. There are still a few ongoing debates about NCGS, most notably regarding its epidemiology, disease recognition, and expert recognition. Some researchers and clinicians do not consider NCGS a genuine disease and believe that it is predominantly a psychosomatic condition that can be fueled by mass media and anxious and confused patients, leading to an overestimated disease prevalence. The persistence in this line of thought hurts patient care and contributes to a general marginalization of patients with non-celiac wheat-sensitive complaints. It only fuels stigmatization, and the objective of the scientific community should be to find a role in the context of gluten-related disease. Overall, there is growing evidence attesting to the existence of patients with non-celiac gluten sensitivity, and several mechanisms have been identified that support the presence of a new pathological condition. Reactive gastrointestinal and systemic symptoms in NCGS might be mediated by the activation of the innate immune system and the activity of neutrophils, changes in gut barrier function and an impaired gut-brain stem axis, viral infections and/or changes in the gut microbiota, β-glucans and amylase-trypsin inhibitors, carbohydrate malabsorption, the type of wheat and gluten, and a placebo/nocebo effect.

3. Debunking Common Myths

Gluten has received more attention in the health and nutrition field than the usual macronutrients like protein and fats. Media has painted gluten to be very unhealthy and a culprit of gaining weight. Despite the numerous headlines against it, gluten isn’t something fundamentally unhealthy. Gluten is just another protein source found abundantly in grains. Grains, in general, are very rich in nutrients and should be consumed daily. Grains offer a good amount of fiber for gut health, energy in the form of complex carbohydrates, healthy fats, and a good amount of essential vitamins and minerals. Enriched grains provide essential nutrients, including iron, niacin, riboflavin, folic acid, and fiber, to our diet that the body can’t make on its own from synthesizing other nutrients.

Should everyone eat pure wheat with gluten all the time? No, gluten or any other protein should be consumed in moderation. One of the biggest problems is that people are quick to eliminate gluten because they think gluten is making them gain weight or feel unhealthy. Many of these same consumers typically will turn around and make a purchase of gluten-free food items that contain sugar, such as gluten-free ice cream, cookies, and cake; all of which were unhealthy to begin with. Furthermore, eating gluten-free products will not guarantee quicker weight loss, weight loss in general, or make you healthier overall. Gluten-free and wheat-free products are not healthier for anyone, and they are not intended for the general public. The public should always look to a registered dietitian or nutrition expert for nutritional advice to ensure the diet meets all of their nutritional needs.