Celiac disease and gluten sensitivity

Celiac disease (pronounced SEE-lee-ak) is a serious medical condition that can cause significant problems if it is not diagnosed and treated properly. It affects the small intestine, the part of the digestive system responsible for absorbing nutrients from food. In people with celiac disease, eating gluten – a protein found in wheat, rye, and barley – damages the lining of the small intestine and can cause inflammation in other parts of the body.

The part of gluten that causes problems is called the prolamin fraction. Different grains contain different prolamins: gliadin in wheat, secalin in rye, hordein in barley, and avenin in oats. Managing celiac disease means avoiding all gluten-containing foods so that the lining of the small intestine can recover. Even small amounts of gluten can cause harm to someone with celiac disease.

How celiac disease damages the bowel#

The normal lining of the small intestine (also called the small bowel) is covered with tiny, finger-like projections called villi. The cells on the villi break down and absorb nutrients from food.

In celiac disease, gluten triggers the immune system to damage this lining (the mucosa). The villi become inflamed and flattened, a change known as villous atrophy. As a result, the surface area available to absorb nutrients and minerals is greatly reduced, which can lead to nutritional deficiencies.

If celiac disease is left untreated, problems that can develop include malnutrition, osteoporosis, depression, and infertility. Untreated celiac disease also carries a small but real increased risk of certain cancers, such as lymphoma.

Symptoms#

The symptoms of celiac disease can range from severe to mild or atypical, and they may even go unnoticed. Some symptoms are wrongly attributed to irritable bowel syndrome or a sensitivity to wheat or other foods, while others may be put down to stress or aging.

Common symptoms in adults include:

• abdominal pain, bloating and flatulence
• diarrhea or constipation
• nausea and vomiting
• bulky, foul-smelling bowel motions
• fatigue, weakness and lethargy
• chronic anemia
• weight loss, although weight gain is also possible

Common symptoms in children include:

• irritability
• diarrhea or constipation
• nausea and vomiting
• stomach cramps, bloating and flatulence
• weight loss or poor weight gain in older children
• delayed growth or delayed puberty
• tiredness

Risk factors#

A large proportion of people carry a genetic predisposition to celiac disease, meaning they have one or both of the “celiac genes” (HLA-DQ2 and HLA-DQ8). Only a small proportion of people who carry these genes – roughly one in 40 – go on to develop the disease, and many who carry the genes never develop it. Environmental factors play an important role in triggering the condition.

If you are diagnosed with celiac disease, your first-degree relatives (a brother, sister, parent, or child) have an increased risk of having it too. For this reason, it is recommended that first-degree relatives be screened. Often, people with celiac disease have no other family members who have been diagnosed, either in their immediate family or in earlier generations.

Celiac disease should also be considered when certain associated conditions or risk factors are present, including:

• early-onset osteoporosis
• unexplained neurological symptoms, particularly peripheral neuropathy or ataxia
• unexplained infertility or recurrent miscarriage
• being a first-degree relative of someone with celiac disease
• persistently raised liver enzymes with no known cause
• other autoimmune disease, such as type 1 diabetes or an autoimmune thyroid condition
• dental enamel defects
• some chromosomal conditions

How celiac disease is diagnosed#

Because the symptoms of other conditions can closely mimic celiac disease, it is important that the diagnosis be confirmed so the right treatment can be given. Your doctor will usually start with blood tests that measure certain antibodies (known as celiac serology).

If the blood tests are positive, your doctor will refer you to a gastroenterologist. The diagnosis is confirmed with a gastroscopy, a procedure in which tiny samples (biopsies) are taken from the small intestine. It is done under sedation, with a slender instrument (an endoscope) passed through the mouth into the small intestine. In some children, celiac disease can be diagnosed without a biopsy if strict criteria are met.

A diagnosis of celiac disease should only be made by a gastroenterologist – do not try to diagnose yourself. For the blood tests and gastroscopy to be accurate, it is important not to start a gluten-free diet beforehand, because these tests depend on a normal gluten intake.

How celiac disease is treated#

At present there is no cure for celiac disease. The only treatment is a strict, lifelong gluten-free diet, which means avoiding all foods that contain gluten.

If you are newly diagnosed, it can feel challenging to find tasty substitutes for the foods you can no longer eat, and the list of foods to avoid may seem very long. Be reassured that you can still enjoy a nutritious, balanced, and delicious diet with a wide range of foods. You can do this by:

• eating naturally gluten-free foods, such as fresh fruit and vegetables; fresh, unprocessed meat and fish; eggs; nuts; seeds; legumes; most dairy foods; fats and oils; and alternative grains such as corn, rice, quinoa, sorghum, buckwheat, and soy
• choosing products labeled gluten free
• selecting products that contain no gluten ingredients, which means becoming very familiar with which ingredients contain gluten and which do not

Some gluten-containing foods are easier to identify than others. Foods with a gluten-containing grain as a main ingredient – such as bread, breakfast cereals, cakes, biscuits, pizza, pasta, pastry, couscous, and semolina – are usually easy to spot and avoid.

Many other prepared and commercial foods also contain gluten, so it is important to read labels carefully. Gluten can be hidden in foods and drinks such as:

• beer and malted drinks
• soy sauce, yeast extract spreads, stocks, gravies, and soups
• sauces, dressings, and some condiments
• sausages, hamburgers, crumbed and marinated meats, and processed deli meats
• confectionery, ice cream, custard powder, icing sugar mixtures, and baking powder

To follow a gluten-free diet safely, you need to become “ingredient aware.” A qualified dietitian can give you advice on which ingredients to avoid and how to plan a balanced gluten-free diet.

A note on oats#

Testing for gluten can measure gliadin from wheat, hordein from barley, and secalin from rye, and a separate test for avenin in oats is also available. Food-labeling rules differ from place to place: in some regions oats can be marketed as gluten free, while in others they cannot. Where oats are labeled gluten free, this generally means there is no measurable contamination with wheat, rye, or barley.

Evidence shows that uncontaminated oats are well tolerated by most people with celiac disease. However, in some people oats can still trigger a potentially harmful immune response. The absence of symptoms when eating oats does not necessarily mean they are safe, because bowel damage can still occur without symptoms. If you wish to include oats in your gluten-free diet, do so under medical supervision. A gastroscopy and small bowel biopsy before and after about three months of regular uncontaminated oat consumption can help guide whether oats are safe for you.

Avoiding cross-contamination#

Even a very small amount of gluten can damage the small intestine, so it is important to avoid cross-contaminating gluten-free foods when preparing, cooking, and serving them. Steps you can take include:

• storing gluten-free products in separate, sealed, labeled containers
• making sure all cooking utensils, appliances, and surfaces used for gluten-free food are clean and free of gluten
• using a clean pot and clean water to cook gluten-free pasta, and straining it with a clean strainer
• protecting gluten-free food from contamination when cooking it alongside gluten-containing food, and not sharing utensils for stirring or serving
• avoiding spreads and condiments that may contain crumbs, by keeping your own labeled gluten-free condiments or using a “single-dip” policy
• using clean oil when deep frying at home (or frying your gluten-free item first), and avoiding food fried in oil also used for crumbed or battered foods
• washing your hands after handling gluten-containing foods

Food labeling and gluten#

All packaged foods carry an ingredient list. Under mandatory labeling standards in many countries, ingredients and additives derived from gluten-containing grains must be declared, and the presence of gluten must be stated. Where a product is labeled gluten free, testing must show no detectable gluten, and where gluten is present above set limits the label must say it contains gluten. Checking labels every time is the safest approach.

Medications and gluten#

Gluten can also be present in some medications. If you are diagnosed with celiac disease, ask your doctor and pharmacist to confirm that any medicines you take by mouth are suitable.

Key points#

• Celiac disease is an autoimmune condition in which gluten damages the lining of the small intestine and can cause inflammation elsewhere in the body.
• Even small amounts of gluten can cause harm, and the damage (villous atrophy) reduces the bowel’s ability to absorb nutrients.
• Symptoms vary widely and can be mild, severe, or absent, so diagnosis should be confirmed by a gastroenterologist before starting a gluten-free diet.
• The only treatment is a strict, lifelong gluten-free diet, including care to avoid cross-contamination and hidden gluten in foods and medicines.

Where to get help#