Bloating after eating: allergy or intolerance?
Bloating after meals is common and annoying, and people often reach for an allergy test first. Here is the straight answer: bloating on its own is rarely a food allergy. Our test measures IgE sensitisation to 300 allergens and allergen components. It does not test for food intolerance, and this page explains the difference.
Allergy and intolerance are different things
A food allergy involves the immune system. IgE antibodies recognise a food protein and trigger a fast reaction, usually within minutes to two hours: hives, itchy mouth, swollen lips, vomiting, wheezing. That is what our test measures.
A food intolerance does not involve IgE. Lactose intolerance, for example, happens because the gut makes too little lactase, the enzyme that breaks down milk sugar. Undigested lactose is fermented by gut bacteria, which causes gas, bloating and loose stools. Fructose malabsorption and sensitivity to fermentable carbohydrates (FODMAPs) in onions, beans and wheat work in a similar way. None of these show up on an IgE test.
What we don't measure, and why
Some tests sold as food intolerance tests measure IgG antibodies to foods. IgG to foods is a normal sign that you have eaten them, and the European Academy of Allergy and Clinical Immunology (EAACI) advises against IgG food tests for diagnosing food allergy or intolerance. We do not offer it.
If you suspect lactose intolerance, a doctor or dietitian can advise on how to check it.
When an allergy test can be relevant
If bloating comes with other signs within a couple of hours of eating, an IgE allergy is more worth considering:
- Itchy mouth, tingling or swollen lips.
- Hives or flushing on the skin.
- Vomiting soon after a specific food.
- Wheezing or a hoarse voice.
What the test shows
The lab checks IgE to 300 allergens and allergen components, including cow's milk, hen's egg, wheat, soy, peanut, hazelnut, fish and shellfish. Each gets a measured value and class, from Negative to Very high. A Negative cow's milk result does not rule out lactose intolerance; it only means no IgE to milk proteins was measured.
Coeliac disease, an immune reaction to gluten, is also not an IgE allergy, and doctors diagnose it with different tests. If coeliac disease is a question for you, talk to a doctor before you change your diet.
When to see a doctor first
See a doctor if bloating comes with weight loss you can't explain, blood in your stool, persistent diarrhoea or constipation, vomiting, night-time symptoms, anaemia, a family history of bowel cancer or coeliac disease, or if it started after age 50. These need investigating, and an allergy test is not the right tool.
Allergens often linked to this
Related symptoms
300 allergens. One test.
A finger-prick sample at home, sent by post. A detailed lab report typically 5 days after the lab receives your sample, and our plain-English guide to reading it. €300, €1 per allergen.
Questions
Will this test tell me if I'm lactose intolerant?
No. Lactose intolerance is an enzyme issue, not an immune reaction, so it does not involve IgE. A doctor can advise on the right test. Our test shows IgE sensitisation to milk proteins, which is a different question.
Do you test IgG for food intolerance?
No. We test IgE, the antibody involved in allergy. IgG to foods mostly reflects what you eat, and EAACI, the European allergy society, advises against IgG food tests for diagnosing food allergy or intolerance.
Can a food allergy cause bloating?
It can be part of an allergic reaction, but it rarely appears alone. Allergic reactions to food usually also involve the skin, mouth or breathing, and start within about two hours.
Is wheat allergy the same as gluten intolerance or coeliac disease?
No. Wheat allergy is IgE-mediated and the test checks for it. Coeliac disease is a different immune reaction to gluten that doctors diagnose with different tests. Non-coeliac gluten sensitivity has no reliable lab test.