Celiac disease: symptoms, causes, diagnosis and going gluten-free

Celiac disease is a chronic autoimmune condition affecting the small intestine, triggered when someone with a genetic predisposition consumes gluten – the protein found in wheat, barley, and rye.

Unlike a simple intolerance, celiac disease involves an immune response that damages the lining of the gut, affecting nutrient absorption and overall health.

What celiac disease is and how it shows up

In people who develop celiac disease, specific components of gluten (mainly gliadin) trigger an immune response that leads to inflammation and atrophy of the intestinal villi – tiny finger-like projections that absorb vitamins, minerals, and other nutrients.

When these villi are damaged, the body struggles to absorb essential nutrients, potentially affecting multiple systems in the body.

Celiac disease can appear at any age, in both children and adults, following the introduction of gluten into the diet.

While it’s often recognised in early childhood in its classic form, many adults are diagnosed later because their symptoms aren’t immediately linked to the gut.

At present, there is no drug-based cure for celiac disease.

The only proven and effective treatment is a strict gluten-free diet for life.

Genetics, predisposition and family links

Celiac disease has a strong genetic component, but having the relevant genes doesn’t automatically mean someone will develop it.

The predisposition is closely linked to certain HLA alleles (especially HLA DQ2 and/or HLA DQ8), found in most people with celiac disease but also in a significant portion of the general population who never develop the condition.

The condition tends to run in families: having a first-degree relative with celiac disease significantly increases your risk compared to the general population. However, what’s inherited is the genetic predisposition, not the disease itself.

Key symptoms of celiac disease

Symptoms of celiac disease are not all gut-related and can vary widely, making diagnosis tricky.

Common (but not exclusive) signs include:

• Persistent gastrointestinal issues like chronic diarrhoea, bloating, cramps, and constipation.
• Nutrient malabsorption, which can cause iron-deficiency anaemia, weight loss, or osteoporosis/osteopenia due to lack of calcium and vitamin D.
• Extra-intestinal symptoms such as chronic fatigue, itchy skin rash (dermatitis herpetiformis), headaches, depression, or neurological issues.
• In children, growth delays, late puberty, or poor weight gain may occur.

Since these symptoms aren’t unique to celiac disease, medical diagnosis through blood tests and, if needed, biopsy is essential.

Celiac disease vs non-celiac gluten sensitivity

A common point of confusion is the difference between celiac disease and non-celiac gluten sensitivity (NCGS).

Celiac disease is a well-defined autoimmune condition that causes documented intestinal damage, requires clinical and biopsy confirmation, and needs a lifelong gluten-free diet.

Non-celiac gluten sensitivity occurs when some people report similar symptoms (bloating, fatigue, headaches, etc.) after eating gluten, but show no intestinal damage or autoimmune markers typical of celiac disease.

This condition is still under study and has no definitive diagnostic tests.

Going gluten-free: what to avoid

For someone with celiac disease, going gluten-free isn’t just saying “no to bread.” It’s about recognising which foods and ingredients contain this harmful protein.

Foods to avoid completely include anything containing wheat, barley, or rye, such as pasta, bread, pizza, biscuits, beer, certain sauces, and processed foods.

Less obvious ingredients like malt, semolina, spelt, triticale, or wheat bran should also be excluded.

On the other hand, plenty of foods are naturally gluten-free: rice, maize, quinoa, potatoes, legumes, fruit, vegetables, meat, fish, eggs, milk, and cheese (as long as they aren’t cross-contaminated during processing).

Packaged products should carry a “gluten-free” label, ensuring gluten content is below levels considered safe for celiacs (below 20 ppm, as required by European regulations).

Links with other conditions

Celiac disease may co-occur with other autoimmune disorders like type 1 diabetes or autoimmune thyroiditis, as well as conditions like dermatitis herpetiformis.

If untreated, celiac disease increases the risk of long-term complications, including osteoporosis, infertility, certain intestinal cancers, and other systemic issues.

Gluten-dree diet: balance, safety and quality

A gluten-free diet is the only effective treatment for celiac disease.

However, “gluten-free” doesn’t automatically mean nutritionally balanced; many industrial alternatives can be low in fibre, vitamins, and minerals.

That’s why it’s important to rely on high-quality products and, if needed, guidance from a specialist nutritionist.

Products like ProLon®, including the Fasting-Mimicking Diet, are certified gluten-free and designed to combine safe eating with a balanced nutritional profile.

This allows people with celiac disease to follow structured eating programmes without worrying about gluten contamination, keeping their diet both safe and nutritionally sound.