Celiac Disease: What Published Guidance Supports

Key takeaways

• Trigger: gluten, found in wheat, barley and rye
• Testing: blood tests, then usually an upper endoscopy with biopsy
• Most useful single change: Ask for testing before removing gluten from your diet.
• Commonest mistake: Going gluten-free before testing, which can make results falsely normal.
• See a doctor if any of the signs under "When to speak to a doctor" below apply to you.

What it is

An autoimmune condition in which gluten damages the lining of the small intestine. It sits within Digestive Health. Below are the published figures, in one place.

The numbers, in one place

What helps

The advice below comes straight from the guidance cited at the foot of this page.

• Ask for testing before removing gluten from your diet
• Keep eating gluten regularly until tests are done
• Ask for a referral to a registered dietitian after diagnosis
• Encourage parents, siblings and children to ask about testing, as they are at higher risk

What to avoid

What to steer clear of, and why it catches people out.

• Going gluten-free before testing, which can make results falsely normal
• Assuming "may contain" products are safe
• Oats not labeled gluten-free, which are often cross-contaminated

In depth

In celiac disease, the immune system reacts to gluten, a protein in wheat, barley and rye. When gluten is eaten, immune cells in the small intestine trigger inflammation that flattens the villi, the tiny finger-like projections that absorb nutrients. With fewer villi, the bowel absorbs less iron, calcium, folate and other nutrients, which explains many of the effects outside the gut, such as anemia, tiredness and weak bones. Some people have few gut symptoms at all and are diagnosed only because of these effects.

Celiac disease requires specific genes, HLA-DQ2 or HLA-DQ8, but most people with these genes never develop it. Something else, possibly infections, gut bacteria or the timing of gluten exposure, appears to trigger the disease in some people. It can start at any age, from early childhood to old age. It affects roughly 1 percent of people, but many have not been diagnosed because their symptoms are varied, mild or blamed on something else.

The disease is not an allergy and not the same as non-celiac gluten sensitivity, in which people report symptoms after eating gluten but do not have the immune markers or intestinal damage of celiac disease. The difference matters, because celiac disease requires strict lifelong avoidance of even small amounts of gluten, and untreated celiac disease can lead to complications such as osteoporosis, infertility and, rarely, small bowel lymphoma. These risks fall once a strict diet is in place.

Signs and symptoms

• Chronic diarrhea or constipation, bloating and gas
• Fatigue and iron-deficiency anemia that does not respond to iron
• Unexplained weight loss, or poor growth and delayed puberty in children
• An itchy, blistering skin rash called dermatitis herpetiformis
• Mouth ulcers and dental enamel defects
• Bone thinning, joint pain or tingling in the hands and feet
• Raised liver enzymes or fertility problems

Causes and risk factors

• Carrying the HLA-DQ2 or HLA-DQ8 genes
• A parent, sibling or child with celiac disease
• Type 1 diabetes or autoimmune thyroid disease
• Down syndrome, Turner syndrome or Williams syndrome
• IgA deficiency
• Other autoimmune conditions

How it is checked

Testing usually begins with a blood test for tissue transglutaminase IgA antibodies (tTG-IgA), together with a total IgA level, because people with low IgA can have falsely negative results. If IgA is low, other antibody tests are used. These tests are only accurate while you are regularly eating gluten. If you have already cut gluten out, your doctor may ask you to reintroduce it for several weeks before testing.

If blood tests are positive, an upper endoscopy with biopsies from the small intestine usually confirms the diagnosis by showing damage to the villi. In children with very high antibody levels, some gastroenterologists may diagnose without a biopsy. Genetic testing for HLA-DQ2 and DQ8 can help rule celiac disease out, because people without these genes are very unlikely to have it, though a positive gene test alone does not diagnose it.

Treatment and support options

A strict gluten-free diet

The only treatment is removing gluten completely and permanently. This means avoiding wheat, barley and rye, including hidden sources such as malt, brewer's yeast, some soy sauces and many processed foods. Rice, corn, potatoes, quinoa, meat, fish, eggs, dairy, fruit and vegetables are naturally gluten-free. Oats labeled gluten-free are tolerated by most people, though a few react to oats themselves. Check labels on medicines and supplements as well.

Working with a dietitian

A registered dietitian experienced in celiac disease can teach you to read labels, spot cross-contamination risks, eat out safely and keep your diet balanced. Gluten-free processed foods can be lower in fiber, iron and B vitamins and higher in sugar and fat than the foods they replace, so the emphasis is on naturally gluten-free whole foods, with specialty products used where they genuinely help.

Correcting deficiencies

At diagnosis your doctor may check iron, folate, vitamin B12, vitamin D and calcium levels and recommend supplements to correct any shortfalls. A bone density scan may be suggested for adults, since poor calcium absorption can thin the bones. Most deficiencies improve as the intestine heals on a gluten-free diet, so supplements are often needed only for a time. Your doctor will recheck levels to decide when to stop.

Follow-up care

Antibody levels are usually rechecked after several months and then periodically, to confirm they are falling, which suggests the diet is working. Yearly follow-up also covers symptoms, weight, nutrition and related conditions such as thyroid disease. If symptoms persist despite a careful diet, your doctor will look for hidden gluten, other conditions or, rarely, refractory celiac disease. Ask for a referral to a gastroenterologist if this is the case.

Prevention

• Test before removing gluten if you suspect celiac disease
• Ask about testing for first-degree relatives
• Use separate toasters, cutting boards and spreads at home
• Check labels every time, since recipes change
• Ask restaurants about preparation methods, not just ingredients

Day to day

Adjusting to a gluten-free life takes time. Early on, it helps to focus on naturally gluten-free foods and build a list of trusted products. At home, cross-contamination can be reduced with separate toasters, colanders and spreads, and by cleaning surfaces. Many families find it simpler to make most shared meals gluten-free.

Eating out and traveling require planning. Call ahead to restaurants, explain your needs clearly and ask how food is prepared. Carry safe snacks. Gluten can also appear in some medicines, supplements and lip products, so check with your pharmacist. Connecting with a celiac support group can provide tips and encouragement.

For specific groups

Children

Children with celiac disease may have poor growth, irritability, delayed puberty or dental enamel defects as well as gut symptoms. An early diagnosis and a dietitian's help support normal growth. Schools, camps and friends' families need clear guidance about safe foods, and older children benefit from learning to read labels themselves.

People with type 1 diabetes

Celiac disease is more common in type 1 diabetes, and screening is recommended soon after diabetes is diagnosed and periodically afterward. Untreated celiac disease can make glucose levels unpredictable and cause lows because food is poorly absorbed. Starting a gluten-free diet may change insulin needs, so check glucose closely.

Pregnancy

Untreated celiac disease is linked to fertility problems and pregnancy complications. Following a strict gluten-free diet and correcting deficiencies, especially folate and iron, before and during pregnancy are important. Tell your obstetric team about the diagnosis so they can check your nutrition and blood counts.

Questions to ask your doctor

• Should I keep eating gluten until testing is done?
• Which tests do I need, and is my IgA level normal?
• Do I need an endoscopy to confirm the diagnosis?
• Should my family members be tested?
• Do I need a bone density scan or vitamin tests?
• How will we know the diet is working?

More questions, answered

Is a little gluten okay occasionally?

No. Even small amounts of gluten can cause intestinal damage in people with celiac disease, sometimes without any symptoms you would notice. A strict diet is needed to allow the intestine to heal and to reduce the risk of long-term complications such as bone thinning.

Can celiac disease develop later in life?

Yes. Celiac disease can develop at any age, even in people who have eaten gluten without problems for decades. New digestive symptoms, unexplained anemia, bone thinning or raised liver enzymes in adults can be the first signs, so it is worth asking about testing.

Are oats safe?

Pure oats labeled gluten-free are safe for most people with celiac disease. Regular oats are often contaminated with wheat during growing or processing. A small number of people react to oat protein itself, so introduce them carefully and discuss it with your dietitian.

How long does it take to feel better?

Many people notice improvement within weeks of going gluten-free, but complete healing of the intestine can take months in children and up to a couple of years in adults. Antibody levels usually fall over months, which is one way your doctor tracks progress.

What is non-celiac gluten sensitivity?

Some people report gut or other symptoms after eating gluten but do not have celiac disease. The cause is not clear, and in some cases other components of wheat, such as fermentable carbohydrates, may be responsible. Celiac disease should be ruled out first, while you are still eating gluten.

Is gluten-free food covered by insurance?

Gluten-free food is generally not covered by health insurance, but visits with a registered dietitian may be, along with follow-up blood tests and bone density scans when your doctor orders them. Naturally gluten-free staples such as rice, potatoes and beans are often cheaper than specialty products.

Related topics

• The Evidence on Anemia, Without the Hype (Blood Health)
• The Evidence on Dietary Fiber, Without the Hype (Nutrition)
• Gut Health and Immunity: What the Evidence Actually Says (Immunity)
• Mouth Ulcers: What Published Guidance Supports (Oral Health)

Where to go next

• Celiac Disease, Explained Without the Jargon
• Celiac Disease: A Practical Checklist
• Celiac Disease — the reference entry
• Digestive Health: The Complete Guide
• Bloating: Sorting the Evidence From the Noise
• What the Guidance Really Says About Diarrhea

When to speak to a doctor

See your doctor for persistent diarrhea, bloating, unexplained weight loss, mouth ulcers, fatigue or iron-deficiency anemia. Do not remove gluten before testing. Go to the emergency room or call 911 for severe abdominal pain, persistent vomiting or significant blood in the stool.

Where this comes from

• National Institute of Diabetes and Digestive and Kidney Diseases — Celiac Disease
• FDA — Gluten-Free Means What It Says

How this page was put together

Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.

Medical disclaimer

This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.