Gluten–a group of proteins found in many grains, starches, and flours–has become one of the most polarizing topics in health and nutrition. We’ve all heard, or have taken a stance on, the debate of whether or not non-celiac diagnosed individuals should be avoiding it. Gluten is highly prevalent in our food system and has been around for centuries – is it actually bad for us?

In this article, we discuss sources of gluten and gluten-free foods, the role of gliadin, an overview of gluten-related conditions, testing for celiac and gluten sensitivity, and what current research indicates about its potential link to various health outcomes.

Let’s start with the basics of where gluten can primarily be found.

Common sources of gluten

Common sources of gluten include bread, pasta, baked goods, and cereal.

The main grains, starches, and flours that contain it:

• Wheat, and its derivatives, including:

> Durum

> Einkorn

> Emmer

> Farina

> Farro

> Graham

> Khorasan

> Semolina

> Spelt

> Wheatberries (and Bulgar)

> Other products made from wheat, such as couscous, orzo, seitan

• Barley
• Rye (and pumpernickel)
• Malt
• Triticale

Less obvious sources

Gluten is hiding in some less obvious food sources such as:

• Beers, ales, lagers
• Breading
• Broths and soup bases
• Brown rice syrup
• Candy
• Croutons
• Drinks mixes (i.e. hot chocolate)
• Gravies and marinades
• Meat and fish substitutes
• Modified food starch
• Processed meats
• Salad dressings
• Soy sauce
• Thickeners and coatings

Gluten-free sources

Grains, nuts/seeds, starches, and flours that are gluten-free include:

• Almond meal/flour
• Amaranth
• Arrowroot
• Buckwheat
• Cassava
• Coconut (and coconut flour)
• Corn
• Flax and chia
• Flours made from nuts, seeds, and beans
• Millet
• Montina
• Oats (certified gluten-free)
• Potato (including potato flour and starch)
• Quinoa
• Rice
• Sorghum
• Tapioca
• Teff
• Yucca
• Other gluten-free whole food sources: vegetables, fruits, beans/legumes, nuts, seeds, seafood, meat, poultry, eggs, and dairy

Gluten proteins – the role of gliadin

Gluten is comprised of two storage proteins called gliadin and glutenin. Gliadin plays a key role in the inflammatory and immune response in individuals sensitive to gluten (with or without celiac disease). We can measure gluten sensitivity and immune response in the gut through the GI MAP stool test. When a marker called anti-gliadin sIgA is elevated, significant fecal antigliadin antibodies are present. This indicates an immune system response and potential sensitivity to gluten within the gut environment. Elevated anti-gliadin sIgA may or may not signal a gluten-related condition. Anti-gliadin sIgA can also be impacted by the presence of parasites, bacterial overgrowth, dysbiosis, and low secretory immunoglobulin A (the GI system’s first line of defense against antigens and pathogens).

Gluten-related conditions – an overview

1. Celiac disease – celiac is a hereditary autoimmune condition in which consuming gluten initiates an immune system attack on the lining of the small intestine. The resulting inflammation can lead to a range of detrimental symptoms, including intestinal damage, atrophy of intestinal villi, malabsorption, and malnutrition. A strict gluten-free (GF) diet must be maintained to avoid severe negative health outcomes. In some cases, celiac disease can be initiated after a viral infection, surgery, severe stress, pregnancy, or childbirth.
2. Non-celiac gluten sensitivity (NCGS) – NCGS is a diagnosis for individuals who have not tested positive for celiac disease and are not allergic to wheat but experience a resolution to their symptoms (which can be intestinal and/or extra-intestinal) once they stop consuming gluten. These symptoms can include bone and joint pain, headaches/migraines, brain fog, depression, nutrient malabsorption, skin reactions (rash, eczema), and a variety of gastrointestinal issues (bloating, diarrhea, abdominal cramping, constipation). There is growing evidence that those with NCGS may experience an immune attack of the gut lining and increased permeability of intestinal mucosa.
3. Wheat allergy – individuals with a wheat allergy are allergic to at least one of the proteins found in wheat. Symptoms may include itchy eyes, mouth, and/ or throat, skin rash, headache, nausea, cramping, vomiting, shortness of breath, or anaphylaxis. If you test negative for a wheat allergy, it’s still possible to have a sensitivity to gluten. Wheat allergies are diagnosed with a positive IgE blood test and food challenge.
4. Dermatitis herpetiformis – those with dermatitis herpetiformis have an autoimmune reaction to gluten ingestion that manifests on the skin as a severe and itchy rash that can be painful and result in blistering. Those who experience this autoimmune skin reaction may not test positive for celiac disease.

Testing for celiac and NCGS

We have worked with many clients who have already received a celiac diagnosis or suspected gluten sensitivity to create a symptom management and health optimization plan. If celiac disease or NCGS is suspected and untested, we order a comprehensive blood panel here at Birchwell. This panel measures antibodies (Total IgA, Anti-tTG IgG, Anti-tTG IgA, Anti-Gliadin IgG, Anti-DGP IgA) and genetic markers (HLA-DQ2 and HLA-DQ8). A deficiency in IgA can result in false negatives on Anti-tTG and EMA IgA tests, which is why a total IgA measurement is included. In these cases, a measurement of Anti-DGP IgG antibodies can still be utilized. Important note: antibody testing will be inaccurate if you are already on a gluten-free diet. You must be actively consuming gluten-containing foods for antibodies to be displayed.

While this testing is a crucial first step, it is not diagnostic. Celiac diagnosis is a somewhat complex process that is classified by several subtypes. An endoscopy and intestinal biopsy by a physician are usually needed, which assess several factors and signs of damage. However, a positive biopsy result on its own (without the presence of antibodies or genes associated with celiac) is not sufficient for diagnosis. Genetic testing alone is also not diagnostic but can provide a more comprehensive clinical picture and indicate susceptibility.

NCGS does not currently have established diagnostic criteria or a specific biomarker, despite high estimates of its prevalence among patients. Research also indicates that IBS and NCGS frequently occur simultaneously with overlapping symptoms, making diagnosis more challenging. However, research to develop standardized diagnostic criteria is growing and successful symptom management has been possible for many patients with individualized nutrition, lifestyle, and supplement protocols.

What the current body of research says

Overall, research on gluten in the food system and its potential involvement in various health conditions is growing but still mixed. 

Pilot studies and small clinical trials have indicated that it may play a role in conditions such as Hashimoto’s thyroiditis, rheumatoid arthritis, lupus, irritable bowel syndrome, and neurodegenerative diseases in susceptible populations. Both celiac and NCGS have been linked with various autoimmune conditions. Thus, individuals with a predisposition to autoimmune disease seem to be the most at risk of experiencing issues with gluten. At Birchwell, we typically find that clients with autoimmune conditions feel better and experience symptom reduction when avoiding gluten.

Recent research indicates that gluten does not appear to be problematic for healthy individuals without a physiological susceptibility or sensitivity to it.

While the overall body of evidence is inconclusive and requires larger-scale randomized controlled trials to clearly identify gluten’s potential role in these conditions, the clinical experience of qualified practitioners is paramount to informing optimal symptom management and individualized care for gluten-sensitive individuals.

Theories behind the rise in gluten sensitivity

There are differing theories hypothesizing contributions to the rise in gluten sensitivity and intolerance:

1. Molecular mimicry – molecular mimicry has been identified as a factor in the pathogenesis of many autoimmune diseases. Molecular (or antigenic) mimicry occurs when the immune system confuses two different antigens due to a functional, structural, or immunological similarity between them. For example, the immune system can confuse gliadin proteins with transglutaminase enzymes (found in the thyroid gland) due to their similar structures. Intestinal hyperpermeability can allow gluten molecules into the bloodstream, triggering immune cells to produce antibodies against gliadin. Similar to bacteria, viruses, or other substances foreign to the body, gluten proteins are now viewed as a threat to the body’s immune system. When gluten makes its way into the bloodstream, these gliadin antibodies can mistakenly mount an autoimmune attack against the body’s own cells (via the thyroid gland’s transglutaminase enzymes) instead of attacking the similarly structured gliadin proteins. This is one theory behind gluten’s link to autoimmune thyroid disorders such as Hashimoto’s as well other autoimmune conditions.
2. Incomplete enzymatic breakdown via protease – Proteases are used by the body to break down proteins. The issue with gluten proteins is that they cannot be completely broken down by protease, allowing residual gluten to move through the small intestine and potentially create an autoimmune response in susceptible or inflamed individuals. Some research has suggested enzyme replacement therapy for its potential to improve gluten breakdown and sensitivity symptoms.
3. Glyphosate – glyphosate is the active ingredient in the herbicide Roundup (previously produced by Monsanto and now by Bayer) used to control weeds in the production of various food crops. While the EPA’s current stance is that glyphosate does not pose a risk to human health, some research based primarily on experimental and animal models hypothesizes a potential link between the widely used herbicide and intestinal permeability. This research suggests the theories that 1) glyphosate may weaken the tight junctions of the intestinal wall leading to potential systemic inflammation and 2) glyphosate may interfere with the crosslinking of amino acids and transglutaminase enzymatic pathways enhancing gluten sensitivity. Human research in this area remains unsurprisingly difficult due to ethical issues.

Gluten – Final Thoughts

The research on gluten’s impact on human health is still evolving. If you suspect you have a sensitivity to it or notice particular symptoms after consuming foods that contain it, it’s worth further investigation. A negative test for celiac and/or wheat allergy does not rule out the potential for NCGS, an inflammatory response, or immune response to the consumption of gluten-containing foods (especially if you have an autoimmune condition). There are indeed many ultra-processed GF food products as there are ultra-processed gluten-containing products. Nutrient-dense, healthy, and balanced GF diets, when needed, are absolutely achievable with professional nutrition guidance and planning (that’s where we come in). However, if you don’t currently experience any negative symptoms after consuming gluten, you don’t need to avoid it and can incorporate it as part of a balanced diet.