How much gluten is too much for a person with celiac disease?

The limit of gluten for people suffering with celiac disease is 10 mg per day. It is based on the study by Catassi et al. When those with celiac disease have a limit of 10 mg, it means that they can only have 10 mg altogether in a day to not cause villous atrophy. For example, imagine 10 mg as a pen point of flour, 350th of a piece of bread, or even just a crumb! The only way of managing celiac disease is to have a gluten-free diet, a diet that excludes all grains (barley, rye, oats and wheat). Sometimes, people can buy products that are "gluten-free.” There are strict standards for a product to be "gluten-free,” according to the FDA (Food and Drug Administration), the product has to contain less than 20 ppm/kg (parts per million) to be considered gluten-free. The level of 20 ppm is equal to 20 mg and is the lowest amount that can be detected consistently with scientific tools. Gluten-free bread does not have any gluten, it is made with flours that have zero gluten in it. It is often confused with low gluten bread which contains gluten but to a lesser extent. Also, if a person with celiac disease would like to receive the Holy Communion during Mass, they can receive an alternative—a low gluten host! The low gluten host still has traces of gluten, but has low enough traces for it to become tolerable for people with celiac disease (or gluten sensitivity). The low gluten communion contains about 0.0019 mg. People that suffer from celiac disease can even react to the cross-contamination of gluten left on production lines or kitchen equipment. To avoid cross-contamination, some may wash kitchen equipment very clean or even just have a separate set of kitchen equipment for the person diagnosed with celiac disease. In some cases, even if the air has gluten particles in it, such as a bakery or a sandwich shop, the person suffering with celiac disease can get a reaction as breathing in gluten is another way of ingesting it.

What is celiac disease?

Celiac disease is an inherited, autoimmune disease that can develop at any time and is not curable and leads to malabsorption or the inability of the intestines to absorb nutrients. Celiac disease is also known as gluten-sensitive enteropathy, non-tropical sprue, and celiac sprue. The word “celiac”, originated from a Greek physician named Aretaeus of Cappadocia in the second century AD. The name "celiac", which comes from the Greek word "koiliakos", meaning abdominal, was used by the Greek physician to describe a case of celiac disease that included symptoms like diarrhea and malabsorption. A person's risk of developing celiac disease is 1 in 10 if they have a first-degree relative with the condition, such as a parent or sibling. People with celiac disease often have inherited genetic mutations that predispose them to abnormal immune responses when exposed to certain environmental factors. The abnormal immune response is triggered by the consumption of gliadin, a component that makes up gluten. It is a structural protein found in certain cereal grains. When exposed to gluten, the immune system is inappropriately activated, leading to the production of antibodies and inflammatory cells targeting gluten. This results in damage to the small intestine lining and flattening of the villi (villous atrophy) in the mucosal lining. Villous atrophy leads to a significantly decreased effective mucosal surface area which in turn results in the insufficient absorption of nutrients from our diet.

What exactly is gluten?

Gluten is a naturally-occurring protein found in barley, rye, oats, and wheat (easy to remember with the acronym B.R.O.W.). It contributes to the unique texture and flavour of foods made of these grains. Gluten is commonly found in foods such as pasta, bread, cookies, cake, cereals, etc. Gluten is composed of two proteins, gliadin and glutenin. 

How many people suffer from celiac disease worldwide?

Celiac disease can affect 1 in 100 people across the globe, but only 30% of people are properly diagnosed. Celiac disease can develop at any age after an individual has started consuming gluten. If an individual has a first degree relative, they will have a 1 in 10 chance of developing celiac disease. It mainly develops in people between 8-12 months old, in early childhood, and between the ages of 40-60. According to “The Canadian Celiac Health Survey," the average age of adults getting diagnosed with celiac disease is 46. The ethnic group that is most likely to receive celiac disease are Caucasians of Western European descent. Additionally, females are diagnosed more commonly than males are.

Why is it so important to avoid gluten when you have celiac disease?

It is really important as a person with celiac disease to avoid gluten because eating the slightest amounts can cause damage to the small intestine lining. This can lead to mild to moderate symptoms such as abdominal pain, cramping, weight loss and diarrhea. Over time, the damage to the small intestines and villi may lead to poor absorption of nutrients. This is known as malabsorption. Malabsorption can lead to more severe complications including growth restriction and sometimes organ dysfunction. Late complications can also include the development of certain types of rare and aggressive cancers.

What are some barriers to following a gluten-free diet?

There are many barriers to why someone with celiac disease may have trouble following a gluten-free diet. According to publications from North America, Europe and Asia, some of the common obstacles to gluten restriction are poor access to information as to which foods contain gluten, inability to pay for gluten-free foods and poor motivation in following a restricted diet. At times, if there is external pressure from friends and family this can lead to a lack of support for maintaining this diet restriction. For some individuals, gluten-free foods may not be easily available locally or they may not be able to find gluten-free versions of foods they normally eat. Some patients can find it difficult to avoid consuming foods with gluten at religious celebrations and social gatherings. There can also be a lack of nutritional counseling available to help educate patients.

How do you diagnose celiac disease?

Some ways to diagnose celiac disease is to have serology testing, genetic testing or an upper GI endoscopy. A serology test is a blood test that detects how many antibodies against a certain protein are in the individual’s blood. The most sensitive serologic test looks at antibodies against tissue transglutaminase (tTG). Higher levels of anti-tTG in the blood correlate with an immune system activation by gluten. Genetic testing can be used to examine celiac disease. However, it is more effective in ruling out the disease and or for family screening.  This test looks for a mutation in either the HLA DQ2 and DQ8 genes. Mutations in these genes are associated with a high risk of developing celiac disease. Statistically, HLA DQ2 genes and celiac disease is 90-95% of individuals. People with DQ8 genes and have celiac disease are 5-10% of individuals. If an individual has these genes, it is not guaranteed for them to have celiac disease. Even though 30% of people have HLA DQ2 and DQ8 genes, only 3% of people will develop celiac disease. An endoscopic biopsy is when a doctor will have a long tube with a small camera attached to the end of it. It will then be inserted through the mouth and into the intestines to see if there is a flattening of villi. In some severe cases of celiac disease, the villous atrophy may involve large sections of the small intestine, and this can be visualized by a capsule endoscopy. A capsule endoscopy is when a small camera in a pill sized capsule is swallowed. As it travels through the intestines, it takes images to show doctors if the individual has easily visible changes (macroscopic) or not.

How do you know if a person with celiac disease is compliant?

The gold standard to assess for adequate gluten restriction is to perform an upper endoscopy with biopsies of the small intestine to look for absence of villous atrophy. However, an upper endoscopy is invasive and can be associated with small risk of serious complications such as bowel perforation. Therefore, other less invasive tests are preferred such as serial serology testing. People with celiac disease have higher circulating levels of antibodies in their blood against proteins such as . In a serology test, it can show increased levels of tTG. According to a 2016 study in The American Journal of Gastroenterology¹, they were able to measure a patient's compliance to the gluten-free diet by checking their stools. Gluten immunogenic peptides (GIP) are pieces of gluten that a body of someone that is suffering from celiac disease can not break down. The GIP can cause harm to their small intestine and make them feel unwell. As a result, these gluten pieces show in their stools, it helps doctors see if they are following a gluten-free diet. In the study, they found that 18% of celiac disease patients had gluten pieces in the stools. Interestingly enough, most of the compliance seen was from more of the younger patients (age 3 being the most compliant). Their compliance seemed to increase with each age group. Additionally, they found that men had greater likelihood of having gluten pieces in their stools than women did.

How does gluten affect the intestines of a person with celiac disease?

Gluten can harm the small intestine of a person with celiac disease by damaging the villi, which are tiny finger-like structures in the lining of the intestine. Normally, most people can handle small pieces of undigested gluten as the enzyme, protease, can’t fully break it down. In people with celiac disease, when gluten is eaten, the undigested pieces pass through cells called enterocytes, which are on the surface of the villi. These gluten pieces then build up under the enterocytes, sending a signal to the immune system that something is wrong. The immune system then attacks the enterocytes, causing damage. This leads to gaps between the enterocytes, where there should normally be tight connections. These gaps allow even more undigested gluten to pass through, which makes the damage keep happening.

Are there different types of celiac disease?

Yes, there are. They are separated into 3 different categories: classical, non-classical, and silent/asymptomatic. Classical celiac disease is when someone shows symptoms of abdominal pain, weight loss, diarrhea, steatorrhea (fatty stools), and also signs of malabsorption. Non-classical celiac disease is when someone shows no signs of malabsorption, although they may have symptoms such as diarrhea, stomach pain, etc. Silent celiac disease, also known as asymptomatic celiac disease, is when someone shows no symptoms at all but still has villous atrophy damage (flattening of villi) to their small intestine. The cause of villous atrophy is because of repeated gluten intake.

What are some complications of celiac disease?

Some complications include:

• Iron deficiency which leads to anemia (low supply of red blood cells)
• B12 deficiency which can lead to neurological conditions and anemia as it helps form and regenerate nerves and red blood cells
• Vitamin D deficiency which leads to osteoporosis (low bone mass) and high risk of fractures
• Certain antibodies are overproduced and can deposit in the skin and can lead to dermatitis herpetiformis (rash on the skin)
• The most serious complication that can be seen with celiac disease is the development of cancer of the small bowel and intestinal lymphoma, these are very aggressive diseases and have a poor prognosis

Is there treatment available for celiac disease?

There is no cure for the disease yet, so the only treatment is to have a lifelong diet excluding all gluten products. It will help prevent further damage to the small intestines. Within two years of beginning a gluten-free diet, intestinal mucosal recovery may be complete in up to 95% of children with celiac disease. There is less certainty on the rate of mucosal healing in adults with celiac disease following the gluten-free diet.

What does the gluten-free diet consist of?

The gluten-free diet consists of foods that exclude gluten (barley, rye, oats, wheat, spelt, durum, malt, etc.) and may contain fruits, vegetables, meats and other gluten-free foods. Some items that contain gluten include pastries, pasta, cereal, and even sauces like soy sauce and teriyaki sauce! A good alternative is millet as it is a gluten-free grain.

Adapted from: Caio et al, BMC Medicine, July 23, 2019

In conclusion, my project showed that even small amounts of gluten can be harmful to people with celiac disease. This research made me understand the practical implications and challenges of following a gluten-free diet. This shows how important it is for people with celiac disease to avoid gluten completely to stay healthy. Overall, my project helped me understand more about what celiac disease is, who it affects, and how gluten contributes to it. This project also helped me better understand what people with celiac disease experience and how I can support them

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Margaret Seto, RD Team Lead, Nutrition Services, PLC

I would like to express my sincere gratitude to everyone who helped me complete this science fair project. First, I would like to thank my science teacher for guiding me throughout the project, providing valuable advice, and encouraging me to think critically. I am also very grateful to my parents and family for their constant support, encouragement, and help in gathering materials. A special thanks to my printer, which bravely printed this project despite running low on ink. Finally, I appreciate all the resources, books, and websites that provided useful information for my research. This project would not have been possible without the help and support of all these amazing people.