Can gluten intolerant people eat glucose?

Gluten intolerance, also known as celiac disease, is an autoimmune disorder that affects around 1% of the population. People with celiac disease or non-celiac gluten sensitivity cannot tolerate gluten, a protein found in wheat, barley and rye. When gluten intolerant people eat gluten, it damages the small intestine and prevents it from absorbing nutrients properly. This leads to symptoms like diarrhea, bloating, fatigue and nutritional deficiencies.

Glucose, on the other hand, is a simple sugar that serves as a key source of energy for the cells in our bodies. It is found naturally in fruits, vegetables and honey. Glucose is also produced when carbohydrates are broken down during digestion. For people without gluten intolerance or celiac disease, glucose is generally safe to consume as part of a balanced diet. But can gluten intolerant people also safely eat glucose?

Is glucose naturally gluten-free?

The short answer is yes, glucose is naturally gluten-free. Glucose is a simple sugar molecule made up of carbon, hydrogen and oxygen atoms. It does not contain the proteins found in gluten. Pure glucose is chemically gluten-free.

Glucose occurs naturally in many wholesome, gluten-free foods like fruits, vegetables, honey, maple syrup and sugar cane. It is not inherently derived from gluten-containing grains. When isolated into a pure compound, it does not pose a risk of gluten exposure or intestinal damage for those with celiac disease or non-celiac gluten sensitivity.

Some examples of naturally gluten-free sources of glucose include:

  • Fruits like grapes, apples, bananas, oranges, etc.
  • Vegetables like sweet potatoes, carrots, corn, peas, etc.
  • Honey
  • Maple syrup
  • Sugar cane

Glucose can be safely consumed by gluten intolerant individuals when it comes from these whole food sources. Even white sugar, while highly processed, is derived from sugar cane which is naturally gluten-free.

What about added or processed sources of glucose?

While glucose itself does not contain gluten, there are some potential sources of processed glucose to be aware of:

Corn syrup

Corn syrup is made from cornstarch which is gluten-free. However, since cornstarch is a grain product, there is the risk of cross-contamination with gluten grains during processing. Reputable brands producing corn syrup should follow good manufacturing practices and test for gluten, but it’s still smart for those with celiac disease to choose verified gluten-free corn syrup.


Dextrose is a purified glucose product derived from corn, rice or potatoes. Leading brands of dextrose manufacture their products to be gluten-free to the limit of detection. However, it’s still advisable to look for trusted gluten-free certification on labels. Potential for cross-contamination can exist, especially when dextrose comes from shared corn or rice processing facilities.


Maltodextrin is derived from starchy grains like corn, rice or potato and is used as a food additive. When made strictly from rice or potato starch, maltodextrin avoids gluten exposure. But varieties derived from barley may contain gluten. Checking for gluten-free certification is important with maltodextrin.

Glucose syrup

Glucose syrup, also called confectioner’s glucose, is made by breaking down starch into glucose molecules. Common starch sources include corn, rice, wheat or potato. Wheat-based glucose syrup would contain gluten and must be avoided. But corn or rice-based glucose syrup that is processed in a gluten-free facility would be safe for a gluten-free diet as long as this is confirmed through third-party testing and certification.

Beer brewing products

In beer brewing, sources of glucose like maltodextrin or glucose syrup may be derived from barley malt, containing gluten. Any glucose additives used in beer production would be unsafe.

Other potential sources where cross-contamination may occur include glucose tablets used by diabetics or carbohydrate gels used by athletes. As with any processed food for those with celiac disease or gluten sensitivity, checking labels and product information is important. When sourced from gluten grains, certain glucose additives can pose a hidden risk.

What about glucose tolerance testing for celiac disease?

Healthcare providers sometimes use glucose tolerance testing to help diagnose celiac disease. For this test, a glucose solution is administered orally and blood glucose levels are measured over a period of time.

While the glucose is derived from wheat in some preparations, gluten-free glucose solutions are also readily available. People with known celiac disease or gluten intolerance should be sure to request a gluten-free glucose solution for this test. Most reputable laboratories will accommodate this. With the proper preparation, glucose tolerance testing can be safely performed in those with gluten intolerance.

Tips for identifying safe sources of glucose

For people with celiac disease or non-celiac gluten sensitivity, here are some tips for identifying safe glucose sources:

  • Check labels for gluten-free certification symbols like the crossed grain logo
  • Call manufacturers to inquire about their gluten-free status and testing protocols
  • Opt for glucose sources derived from corn, rice, potatoes or other naturally gluten-free ingredients
  • Avoid glucose sources derived from barley malt or wheat
  • Research glucose additive brands to confirm their gluten-free manufacturing
  • Stick to whole, naturally gluten-free sources like fruits, vegetables and honey when possible

Being an informed consumer and doing some extra homework is key to finding reputable glucose sources that fit into a strict gluten-free lifestyle.

Can glucose tolerance change with celiac disease?

For those diagnosed with celiac disease, adopting a strict gluten-free diet is the key to healing intestinal damage and improving health. Removing gluten sources from the diet allows the gut to start recovering. Over time, this can help resolve malnutrition and return nutrients like glucose to normal absorption levels in the body.

Research shows that successfully following a gluten-free diet can help normalize glucose tolerance in those with celiac disease. In one study, a group of adults with celiac disease who had not been on a gluten-free diet were given a glucose tolerance test. Results showed impaired glucose tolerance in 15% of the untreated celiac patients compared to none of the control group.1

However, after following a gluten-free diet for an average of 1 year, 100% of the celiac patients showed normal glucose tolerance on repeat testing. Their glucose absorption rates returned to the same normal levels as the control group thanks to gut healing on the gluten-free diet.

Additional studies have shown:

  • Children with celiac disease following a gluten-free diet for about 2 years improved glucose tolerance compared to those not on the diet.2
  • healed intestinal damage and normal glucose absorption. 3
  • Adults with celiac disease on gluten-free diets for around 5 years showed glucose tolerance test results in the normal range.4

The overall consensus is that avoiding gluten and following a gluten-free diet allows gut healing and can normalize glucose tolerance in those with celiac disease. Glucose absorption returns to healthy levels once the intestines have recovered from gluten damage.

Should blood glucose levels be monitored with celiac disease?

Given the link between celiac disease and impaired glucose tolerance, monitoring blood glucose levels is recommended for those with celiac, especially:

  • At time of diagnosis before starting a gluten-free diet
  • Children and adolescents with celiac disease
  • Celiac patients who continue having symptoms like gastrointestinal upset that could relate to blood glucose control
  • Celiac patients with other autoimmune diseases like type 1 diabetes where blood glucose is affected

Checking both occasional fasting blood glucose and HbA1c levels can help identify glucose management issues associated with untreated celiac or poor gut healing. Blood glucose testing can also screen for early signs of secondary diabetes development.

Some experts recommend occasional glucose tolerance testing in higher risk celiac patients, especially children. This can trace recovery of glucose tolerance after adopting a strict gluten-free diet. The frequency of glucose screening should be determined on an individual basis with the healthcare team.

Luckily, most celiac patients see their glucose absorption return to normal once on a gluten-free diet. But blood glucose monitoring can be used in concert with celiac disease antibody levels and intestinal biopsies to ensure complete gut healing is achieved.

Are there other links between celiac disease and blood sugar?

Beyond glucose tolerance, researchers have uncovered other associations between celiac disease and blood sugar disorders:

  • Higher rates of type 1 diabetes: Up to 10% of people with celiac disease also have type 1 diabetes. The autoimmune reaction in celiac disease promotes insulin autoantibodies which can damage insulin-producing cells in the pancreas.5
  • Increased risk of developing type 2 diabetes: One study found a 30% increased risk of type 2 diabetes in patients with celiac disease compared to the general population.6 The exact mechanisms require further study.
  • Hypoglycemia: Some case reports have described low blood sugar hypoglycemia occurring in celiac patients, especially children. This may relate to impaired starch digestion.
  • Metabolic syndrome: There is a higher prevalence of metabolic syndrome and related biomarkers like elevated blood lipids and blood pressure levels in some untreated celiac patients.7

Therefore, beyond glucose itself, celiac disease has implications for overall carbohydrate and insulin metabolism. Following a strict gluten-free diet and avoiding gluten cross-contamination are critical for anyone with dual celiac disease and diabetes. Preventing further autoimmune damage helps stabilize blood sugar control.

What about wheat allergy vs wheat and gluten sensitivity?

It’s important to distinguish celiac disease from other conditions like wheat allergy and non-celiac gluten sensitivity:

Wheat allergy

  • An allergic reaction to wheat proteins, not gluten specifically
  • Mediated by IgE antibodies and histamine release
  • Symptoms may include hives, breathing difficulties, or anaphylaxis after eating wheat
  • Complete wheat avoidance is needed as treatment
  • Does not cause the intestinal damage seen in celiac disease
  • Glucose tolerance is unlikely to be impaired

Non-celiac gluten sensitivity (NCGS)

  • Sensitivity to gluten without the autoimmune component of celiac disease
  • Intestinal damage is typically mild or absent
  • Symptoms like fatigue, headaches and diarrhea after gluten exposure
  • May follow a gluten-free diet but not to the extent needed for celiac disease
  • Glucose tolerance can remain normal

Someone following a gluten-free diet for wheat allergy or NCGS does not necessarily have the same glucose absorption issues as an untreated celiac patient. The degree of intestinal damage tends to be much less.

However, any persisting digestive symptoms in wheat/gluten-sensitive individuals may justify checking glucose tolerance from time to time. Impaired nutrient absorption is still possible and can affect blood sugar levels. Monitoring glucose can give insights into intestinal health.


In summary, glucose itself is safe for consumption by those with celiac disease or gluten intolerance when it comes from gluten-free sources. However, some processed types of glucose additives may pose cross-contamination risks if derived from gluten-containing grains.

Celiac patients, especially children, may experience impaired glucose tolerance when diagnosed before starting a gluten-free diet. Thankfully, following a strict gluten-free diet allows healing of the gut lining and typically restores normal glucose absorption within 1-2 years.

Persistent symptoms or multiple autoimmune conditions may justify periodic blood glucose monitoring for those with celiac disease. Testing glucose levels, along with celiac antibodies and intestinal biopsies, can help confirm mucosal recovery and stabilization of blood sugar status on the gluten-free diet.

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