Gluten: What It Is and How It Affects Health

Gluten is a group of proteins in wheat, barley and rye. For most people it is harmless. For people with celiac disease, wheat allergy or non-celiac gluten sensitivity, it causes real problems — and the right test before going gluten-free matters.

Where gluten is found

Wheat (including spelt, durum, semolina, farro), barley and rye — in bread, pasta, baked goods, many cereals, beer, and as a hidden ingredient in sauces, soups and processed foods. Oats are naturally gluten-free but often contaminated; look for certified gluten-free oats. Rice, corn, quinoa, buckwheat, millet and potatoes are gluten-free.

Celiac disease

An autoimmune disease affecting about 1% of people. Gluten triggers an immune reaction that damages the lining of the small intestine. Symptoms vary: diarrhea, bloating, weight loss, anemia, fatigue, skin rash (dermatitis herpetiformis), bone loss — or almost none. It runs in families and is more common with type 1 diabetes and autoimmune thyroid disease.

Diagnosis: a blood test (tissue transglutaminase antibodies) followed by a small-bowel biopsy. Important: keep eating gluten until testing is complete, otherwise the tests can be falsely negative. Treatment: a strict lifelong gluten-free diet.

Wheat allergy

An allergic reaction to wheat proteins, more common in children. Symptoms range from hives and swelling to breathing problems or anaphylaxis. People with wheat allergy usually can eat barley and rye.

Non-celiac gluten sensitivity

Some people have digestive or other symptoms after eating gluten but test negative for celiac disease and wheat allergy. In some of them, fermentable carbohydrates in wheat (FODMAPs) rather than gluten itself may be the trigger. A dietitian can help with a structured elimination and reintroduction.

Is gluten-free healthier for everyone?

No. For people without these conditions, there is no evidence that avoiding gluten improves health. Gluten-free processed products are often lower in fiber and higher in sugar, fat and salt — and whole-grain wheat, barley and rye are linked to lower cardiovascular risk.

Naturally gluten-free whole grains: corn, quinoa, buckwheat, brown rice.