Originally Posted May 2018 / Updated March 2023

Why Do People Follow a Gluten-Free Diet?

Reducing or avoiding gluten consumption has become more common. 

People follow a gluten-free diet mainly to avoid immune system-mediated inflammation and sensitivity reactions related to gluten or digestive disturbances like gas and bloating they experience after eating gluten-containing grains. 

What to Avoid on a Gluten-Free Diet

Gluten and related compounds are a protein complex found in wheat and related grains such as barley, spelt, and rye. 

Oats contain a different type of protein that may also be an issue for those sensitive to gluten. 

Ricequinoa, amaranth, millet, corn, and sorghum do not contain gluten, so that they can be consumed on a gluten-free diet.

Common Issues With Gluten-Containing Foods

Here are some classifications that are important in understanding the range of issues with gluten-containing foods.

Celiac Disease

Celiac disease (CD) is an autoimmune disorder triggered by gluten sensitivity that damages the fingerlike villi of the small intestinal lining. 200 possible symptoms characterize Celiac Disease, but generally gastrointestinal (GI) issues ranging from very mild GI discomfort to severe malabsorption (e.g., diarrhea, malodorous flatulence, abdominal bloating, and increased amounts of fat and undigested food particles in the stool). The symptoms of CD and the structural damage to the small intestine usually revert to normal on a strict gluten-free diet. The definitive diagnosis of celiac disease involved taking a small intestine biopsy. Screening tests now measure IgA antibodies to proteins (transglutaminase and/or endomysium) from blood samples. In patients with celiac disease, these IgA antibodies signify an immune response and sensitivity to gluten.

Non-Celiac Gluten Sensitivity

Non-celiac gluten sensitivity (NCGS) is also an immune-mediated sensitivity to gluten. Still, it does not produce the classic intestinal damage that celiac disease does or have the same blood markers of autoimmunity. People with NCGS develop various intestinal and/or other symptoms that improve when gluten is removed from the diet. 

Gluten intolerance is a term used to describe gastrointestinal symptoms, such as occasional gas and bloating, that are not mediated by the immune system but occur after the ingestion of gluten.

Wheat Allergy

Wheat allergy can mimic NCGS but is associated with testing positive for the immune system reacting to non-gluten proteins in wheat in a classic allergic response. 

Non-Gluten Related Disorder

Non-gluten-related disorder (NGRD) refers to an intolerance to other components of wheat and other grains that are not mediated by the immune system but can produce minor GI symptoms such as occasional gas, bloating, and indigestion. The most common offending compounds are fiber components, especially oligosaccharides, and fructans. 

Why Is it Important to Rule Out Celiac Disease or NCGS?

If all gluten did was cause some minor gastrointestinal symptoms, it might not be a big deal, but there is a growing list of health conditions linked to CD and NCGS. Perhaps the most serious associated condition is early death. A landmark study looked at almost 30,000 CD patients from 1969 to 2008 and examined deaths in four groups: those with full-blown CD, those with inflammation of their intestine but not full-blown CD, those with latent celiac disease or NCGS (elevated gluten antibodies but negative intestinal biopsy), and a control group with no evidence of celiac disease or gluten sensitivity. The findings were significant as compared to the control group, there was a 39% increased risk of death in those with celiac disease, 72% increased risk in those with gut inflammation related to gluten, and 35% increased risk in those with gluten sensitivity but no celiac disease. 

Another review article listed 55 health conditions linked to celiac disease and gluten sensitivity including: irritable bowel disease, inflammatory bowel disease, anemia, migraines, epilepsy, fatigue, canker sores, osteoporosis, rheumatoid arthritis, lupus, multiple sclerosis, and almost all other autoimmune diseases. Additional studies link CD and gluten sensitivity to fatigue, thyroid abnormalities, type 1 diabetes, psychiatric disturbances (including schizophrenia), lower mood scores, impairment of mental function, and autism. A more ominous association is the increased risk for malignant cancers seen in celiac patients, especially for non-Hodgkin lymphoma. 

The bottom line is that it is important to see a physician if you suspect you might have gluten sensitivity and celiac disease because they carry these associations of increased morbidity (disease) and mortality (early death).

How Soon Does a Gluten-Free Diet Work?

In all gluten sensitivity/intolerance forms, gluten elimination usually brings clinical improvement within a few days or weeks. In CD, 30% respond within 3 days, another 50% within 1 month, and 10% within another month. That said, approximately 10% of patients only respond after 24 to 36 months of gluten avoidance. Another way of looking at this data 8 out of 10 cases of CD respond within a month of eating a gluten-free diet.

Check out iHerb’s gluten-free specialty store for gluten-free supplements, foods, bath and beauty items and more!

Digestive Enzyme Supplement Benefits

Digestive enzyme supplements that break down gluten, like dipeptidyl peptidase IV (DPP-IV), can be helpful to offset a low level of accidental gluten ingestion, but they are not a substitute for a gluten-free diet. 

Studies indicate that even on a gluten-free diet, many people with celiac disease or gluten sensitivity are inadvertently exposed to enough gluten to continue producing symptoms. Fortunately, supplementation with gluten-digesting enzymes can help break down the small amount of ingested gluten. 

While gluten-degrading enzymes are not a treatment for celiac disease or NCGS, they can be used as digestive aids to reduce gluten exposure in case of unintentional intake of small amounts of gluten in both disorders.

The FDA has strict criteria and labeling requirements for food manufacturers to label a food “gluten-free.” However, even with this assurance, it seems that people on a gluten-free diet are ingesting enough gluten to cause issues. Eating as little as 10 mg of gluten can cause problems in some sensitive individuals, while most patients with celiac disease can tolerate up to 100 mg daily. However, a recent analysis uncovered the average inadvertent exposure to gluten by people with celiac disease on a gluten-free diet was estimated to be between 150–400 mg/day by measuring the level of gluten metabolites in the urine and stool.

These numbers indicate that avoiding gluten from a gluten-free diet alone is impossible. Supplemental digestive enzyme preparations containing gluten-digesting enzymes may help people break down small amounts of unintended gluten ingestion. 

However, it must be stressed that gluten-digesting enzymes are not a replacement for a gluten-free diet, especially for people with celiac disease or gluten sensitivity. 


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