Gluten is a group of proteins – mainly gliadins and glutenins – found in wheat, rye and barley, as well as in related grains such as spelt. It gives dough its elasticity, helps bread rise and keeps pasta firm.
Strictly speaking, the gluten network forms when flour is mixed with water and kneaded: the proteins link up into a stretchy mesh. The word “gluten” comes from the Latin for “glue”.
For most people, gluten is harmless. For some, however, it causes real health problems – and in recent years, gluten-free eating has also become a trend. This article explains who really needs to avoid gluten and what the research says.
Where is gluten found?
Gluten is found naturally in wheat, rye and barley, and therefore in many processed foods:
- bread, rolls, cakes, pancakes, pizza
- pasta, dumplings, noodles
- breadcrumbs, crackers, pie crusts
- breakfast cereals and muesli
- soy sauce, soup powders, bouillon cubes
- some flavored yogurts and processed cheeses
- some sausages, pâtés and ready meals
- beer made from barley or wheat
- some medications and supplements as an excipient
Note: Oats are naturally gluten-free, but are often contaminated with wheat during cultivation and processing. People with celiac disease should choose certified gluten-free oats. A small proportion of people with celiac disease also react to oat protein itself.
In the EU, gluten-containing cereals must be highlighted in the ingredient list.
Who needs to avoid gluten?
Celiac disease
Celiac disease is an autoimmune disease affecting about 1% of the population. In people with a genetic predisposition, gluten triggers an immune reaction that damages the lining of the small intestine. Possible consequences include digestive problems, weight loss, iron deficiency, osteoporosis, tiredness and, in children, growth problems. Many people have only mild or atypical symptoms and remain undiagnosed for years.
The only treatment is a strict, lifelong gluten-free diet – even small amounts can damage the gut.
Important: Celiac disease is diagnosed with blood tests and usually a biopsy of the small intestine. These tests only work reliably while you are still eating gluten. So get tested before you cut out gluten.
Wheat allergy
A wheat allergy is a classic allergic reaction to wheat proteins, which can cause skin rashes, breathing problems or digestive symptoms. It is more common in children and is diagnosed by an allergist.
Non-celiac gluten or wheat sensitivity
Some people without celiac disease or wheat allergy report symptoms such as bloating, abdominal pain, tiredness or headaches after eating wheat products, which improve on a gluten-free diet. This condition is real, but not yet fully understood. In many cases, it is not the gluten but other components of wheat – especially fermentable carbohydrates called fructans (FODMAPs) – that cause the symptoms.
Has wheat changed?
It is often claimed that modern wheat contains much more gluten than older varieties. Studies comparing old and new wheat varieties have not found a substantial increase in gluten content. What has changed is how we eat: more highly processed foods, faster bread production with less fermentation, and in some products added wheat gluten.
Traditional sourdough breads with long fermentation times break down some of the fructans and may be easier to digest for people with irritable bowel syndrome. For people with celiac disease, however, sourdough bread made from wheat or rye is not safe.
What a gluten-free diet can – and can’t – do
When it helps
- In celiac disease, a gluten-free diet heals the gut lining, relieves symptoms and improves nutrient absorption.
- In dermatitis herpetiformis, an itchy skin condition linked to celiac disease, it clears the skin.
- In non-celiac gluten sensitivity, it can relieve digestive symptoms, tiredness and headaches.
- In irritable bowel syndrome, a low-FODMAP diet, which reduces wheat, can relieve symptoms.
What is not proven
- For people without these conditions, there is no evidence that a gluten-free diet reduces inflammation, gives more energy, improves skin or sleep, or strengthens the immune system.
- Celiac disease is more common in people with other autoimmune diseases such as type 1 diabetes or Hashimoto’s thyroiditis, so screening is recommended for them. Without celiac disease, a gluten-free diet has not been shown to improve these conditions.
- There is no reliable evidence that a gluten-free diet improves ADHD symptoms in children without celiac disease. Children with ADHD and digestive complaints should be tested for celiac disease.
- Gluten does not cause leaky gut in healthy people. In people with celiac disease, it increases intestinal permeability.
Possible downsides
- Whole grains such as wheat, rye and barley are an important source of fiber, B vitamins and minerals. Large studies link whole-grain consumption with a lower risk of heart disease and type 2 diabetes.
- Many gluten-free products are highly processed and contain more sugar, fat and salt and less fiber.
- Gluten-free products are often more expensive.
If you avoid gluten, focus on naturally gluten-free whole foods rather than gluten-free replacement products.
What can you eat instead?
There are many naturally gluten-free foods:
Gluten-free flours and grains:
- buckwheat
- chickpea flour
- coconut flour
- almond flour
- quinoa
- amaranth, teff, millet, brown rice, sorghum, corn
Bread and baking ideas:
- buckwheat bread with flaxseed
- chickpea or pea pancakes
- tarts with a nut base
Vegetables, fruit, legumes, potatoes, nuts, seeds, eggs, fish, meat and dairy products are naturally gluten-free.
Hidden gluten
For people with celiac disease, even small amounts matter. Gluten can be found in:
- spice blends and sauces
- some medications and supplements
- sweets and ice cream
- some flavored coffee drinks
- products prepared on the same surfaces as wheat (cross-contamination)
Always check the label – “organic” does not mean gluten-free. Gluten in cosmetics is only a problem if it is swallowed, for example in lipstick.
Did you know?
- Traditional East Asian cuisines are largely based on rice and therefore contain relatively little gluten – although soy sauce usually contains wheat.
- In Ethiopia, the flatbread injera is traditionally made from teff, a naturally gluten-free grain.
- Tennis player Novak Djokovic has said that a gluten-free diet improved his performance – a personal experience, not a scientific study.
- Celiac disease is one of the most common food-related diseases, yet most people affected are not diagnosed.
Is gluten-free right for you?
If you regularly have digestive problems, tiredness, iron deficiency or other symptoms that could be related to gluten, see your doctor and get tested for celiac disease – while you are still eating gluten. If celiac disease and wheat allergy are ruled out, a dietitian can help you test whether reducing wheat or FODMAPs helps.
If you feel well, there is no need to avoid gluten. A diet rich in whole grains, vegetables, legumes and fruit is one of the healthiest ways to eat.
