Gluten is a group of proteins found in wheat and related grains, including barley and rye. It is responsible for the elastic texture of dough, helping it rise and maintain its shape. Gluten is a crucial component in many baked goods, providing the chewy texture that is often desired in bread and other products.

Composition of Gluten

Gluten is composed of two main proteins: gliadin and glutenin. These proteins are found in the endosperm of the grain and are activated when flour is mixed with water. Gliadin is responsible for the extensibility of the dough, allowing it to stretch, while glutenin provides strength and elasticity. Together, they form a network that traps air bubbles, giving bread its structure and texture.

Sources of Gluten

Gluten is primarily found in:

Wheat (including varieties like spelt, kamut, farro, and durum)
Barley
Rye
Triticale (a hybrid of wheat and rye)

It is also present in many processed foods as an additive for texture and flavor. Common foods containing gluten include:

Bread and baked goods
Pasta
Cereals
Beer
Sauces and dressings

Gluten in the Diet

For most people, gluten is a harmless part of the diet. However, some individuals may experience adverse reactions to gluten, leading to various health conditions.

Celiac Disease

Celiac disease is an autoimmune disorder where the ingestion of gluten leads to damage in the small intestine. It affects about 1% of the population worldwide. When people with celiac disease consume gluten, their immune system attacks the lining of the small intestine, leading to malabsorption of nutrients. Symptoms can include:

Diarrhea
Fatigue
Weight loss
Bloating and gas
Anemia

The only effective treatment for celiac disease is a strict gluten-free diet, which allows the intestine to heal and prevents further damage.

Non-Celiac Gluten Sensitivity

Some individuals experience symptoms similar to celiac disease when consuming gluten, but do not test positive for celiac disease. This condition is known as non-celiac gluten sensitivity (NCGS). Symptoms can include:

Abdominal pain
Bloating
Diarrhea or constipation
Headaches
Fatigue

The exact cause of NCGS is not well understood, and diagnosis is typically made by ruling out celiac disease and wheat allergy. A gluten-free diet is often recommended to alleviate symptoms.

Wheat Allergy

Wheat allergy is an allergic reaction to proteins found in wheat, including gluten. It is more common in children and can cause symptoms such as:

Skin rashes
Respiratory issues
Gastrointestinal problems

Avoiding wheat and wheat-containing products is necessary for managing a wheat allergy.

Gluten-Free Diet

A gluten-free diet excludes all foods containing gluten. It is essential for individuals with celiac disease and may benefit those with NCGS or wheat allergy. Foods that are naturally gluten-free include:

Fruits and vegetables
Meat and poultry
Fish and seafood
Dairy products
Beans, legumes, and nuts

Grains and starches that are gluten-free include:

Rice
Corn
Quinoa
Buckwheat
Millet
Amaranth

Many gluten-free alternatives are available for traditionally gluten-containing foods, such as gluten-free bread, pasta, and cereals. However, it is important to read labels carefully, as gluten can be present in unexpected products.

Considerations and Challenges

Adopting a gluten-free diet can be challenging, as gluten is prevalent in many foods. It requires careful planning and label reading to ensure all sources of gluten are avoided. Additionally, gluten-free products can be more expensive and may lack certain nutrients found in their gluten-containing counterparts.

For those without a medical need, there is no evidence that a gluten-free diet provides health benefits. In fact, unnecessarily avoiding gluten can lead to nutritional deficiencies if not properly managed.

Gluten in wheat: What has changed during 120 years of breeding?

In recent years, the number of people affected by celiac disease, wheat allergy or gluten or wheat sensitivity has risen sharply. But why is this the case? Could it be that modern wheat varieties contain more immunoreactive protein than in the past? Results from a study by the Leibniz-Institute for Food Systems Biology at the Technical University of Munich and the Leibniz Institute of Plant Genetics and Crop Plant Research are helping to answer this question.

Wheat grains contain about 70 percent starch. Their protein content is usually 10 to 12 percent. Gluten accounts for the lion's share of proteins, at around 75 to 80 percent. Gluten is a compound mixture of different protein molecules. These can be roughly divided into two subgroups: "gliadins" and "glutenins."

It has long been known that wheat proteins can trigger disorders such as celiac disease or wheat allergies. Approximately 1 or 0.5 percent of the adult population is affected worldwide. In addition, non-celiac gluten sensitivity (NCGS) is becoming increasingly important in the western world. Many people fear that modern wheat varieties contain more immunoreactive proteins than in the past and that this is the cause of the increased incidence of wheat-related disorders.

60 wheat varieties from the period 1891 -- 2010 analyzed

Analyses by the team of scientists show that, overall, modern wheat varieties contain slightly less protein than old ones. In contrast, the gluten content has remained constant over the last 120 years, although the composition of the gluten has changed slightly. While the proportion of critically viewed gliadins fell by around 18 percent, the proportion of glutenins rose by around 25 percent. In addition, the researchers observed that higher precipitation in the year of the harvest was accompanied by a higher gluten content in the samples. Scherf also points out that not all protein types contained in wheat have been investigated with regard to their physiological effects. Therefore, there is still a lot of research to be done.

Gluten is the main storage protein of wheat grains. Gluten is a complex mixture of hundreds of related but distinct proteins, mainly gliadins and glutenins. Similar storage proteins exist as secalin in rye, hordein in barley, and avenins in oats and are collectively referred to as "gluten." The objective was to discuss the biochemical and functional properties of the gluten proteins, including structure, sources, and dietary intakes. Literature was reviewed from food science and nutrition journals. The gluten protein networks vary because of different components and sizes, and variability caused by genotype, growing conditions, and technological processes. The structures and interactions of this matrix contribute to the unique properties of gluten. The resulting functions are essential to determining the dough quality of bread and other baked products. Gluten is heat stable and has the capacity to act as a binding and extending agent and is commonly used as an additive in processed foods for improved texture, moisture retention, and flavor. Gliadin contains peptide sequences that are highly resistant to gastric, pancreatic, and intestinal proteolytic digestion in the gastrointestinal tract. The average daily gluten intake in a Western diet is thought to be 5-20 g/day and has been implicated in several disorders. Gluten containing grains (wheat, rye, barley, and oats) are important staple foods. Gluten is among the most complex protein networks and plays a key role in determining the rheological dough properties Gluten Review

There are over 100 forms of disease that gluten can exacerbate and contribute to. But, is it the gluten??

Effect of wheat gluten hydrolysate on the immune system in healthy human subjects Activity of NK cells was significantly higher in wheat-eaters than gluten-free eaters. NK cells are an important first line of defense.

Articles/Studies

Biochemistry of Gluten

Risks

Gluten in pharmaceutical products: a scoping review
Clinical and diagnostic aspects of gluten related disorders
Many probiotics are contaminated with traces of gluten
Common weed could spell bellyache for gluten intolerant The gluten-like proteins found in ryegrass could be mixing with crops commonly used as gluten-free products or wheat replacements and causing a reaction among people with coeliac disease or gluten intolerance.
Gluten in pharmaceutical products: a scoping review
Is gluten the great etiopathogenic agent of disease in the XXI century?
The opioid effects of gluten exorphins: asymptomatic celiac disease

Cardiovascular Effects

Long term gluten consumption in adults without celiac disease and risk of coronary heart disease: prospective cohort study Long term dietary intake of gluten was not associated with risk of coronary heart disease. However, the avoidance of gluten may result in reduced consumption of beneficial whole grains, which may affect cardiovascular risk. The promotion of gluten-free diets among people without celiac disease should not be encouraged.

Diabetes

Associations of Gluten Intake With Type 2 Diabetes Risk and Weight Gain in Three Large Prospective Cohort Studies of US Men and Women Our findings suggest that gluten intake may not exert significant adverse effects on the incidence of T2D or excess weight gain. Limiting gluten from diet is thus unlikely to facilitate T2D prevention and may lead to reduced consumption of cereal fiber or whole grains that help reduce diabetes risk.

Low gluten diets linked to higher risk of type 2 diabetes

Child's gluten intake during infancy, rather than mother's during pregnancy, linked to increased risk of developing type 1 diabetes a child's intake of gluten at age 18 months is associated with a 46% increased risk of developing type 1 diabetes for each extra 10g of gluten consumed.

Dietary gluten and the development of type 1 diabetes - PubMed

In infants, amount, timing and mode of introduction have been shown to affect the diabetogenic potential of gluten, and some studies now suggest that a gluten-free diet may preserve beta cell function. Other studies have not found this effect. There is evidence that the intestinal immune system plays a primary role in the pathogenesis of type 1 diabetes, as diabetogenic T cells are initially primed in the gut, islet-infiltrating T cells express gut-associated homing receptors, and mesenteric lymphocytes transfer diabetes from NOD mice to NOD/severe combined immunodeficiency (SCID) mice. Thus, gluten may affect diabetes development by influencing proportional changes in immune cell populations or by modifying the cytokine/chemokine pattern towards an inflammatory profile.

Enteropathy

Gluten-induced enteropathy: the effect of partially digested gluten.

Schizophrenia

Effects of Gluten on Schizophrenics

Previous studies have suggested that a cereal-and milk-free diet may be beneficial to schizophrenics and that the gluten in regular diets is harmful to schizophrenics. In an effort to replicate these findings, with improved control vehicles, patients on a locked ward were placed on a cereal-and milk-free diet. Thirteen schizophrenics were given gluten-free peanut-flour supplementary cookies and 13 were given virtually identical cookies with gluten added. Tests and rating scales before and after the ten-day study period showed no greater improvement for those receiving the gluten-free cookies than for those receiving the gluten-added cookies. Contrary to expectations, the group receiving gluten-added cookies showed significantly greater improvement on Profile on Mood States measures of tension-anxiety and anger-hostility. Previous findings were not supported. Perhaps a longer time on the diet is required for any beneficial effects to appear.

Reducing Harmful Effects

Bacterial-Based Strategies to Hydrolyze Gluten Peptides and Protect Intestinal Mucosa - PubMed

Effects of edible plant polyphenols on gluten protein functionality and potential applications of polyphenol-gluten interactions - PubMed

Tannin-gluten interactions may be used to reduce inflammatory effects of gluten experienced by those with gluten allergies and celiac disease.

Gluten-degrading bacteria: availability and applications - PubMed

Gluten

See Gluten Sensitivities

See Also Whole Grain Foods and Wheat amylase trypsin inhibitors (ATIs)

VIDEOS:

You’ve Been Lied to About Gluten