What should you know about IgG antibodies and food intolerance?

IgG is an antibody your immune system can make after exposure to a food. A detected result may reflect contact with that food rather than an illness or a harmful reaction. Food intolerance usually describes symptoms caused by difficulty digesting or processing a food, rather than a classic immediate allergy. Bloating, abdominal discomfort and diarrhoea can have many explanations, so a single antibody result cannot identify the cause.

A clinician may review when symptoms begin, how long they last, what you eat, medicines, bowel changes and your general health. Other conditions can resemble food intolerance, including coeliac disease or infection.

Keep a brief food-and-symptom diary, recording portions, timing and symptoms without removing many foods at once. Take the report to a clinician and ask whether a supervised elimination and reintroduction plan is appropriate. Avoid restrictive diets based only on an IgG panel, because cutting several foods can reduce variety and make it harder to identify the true trigger. A registered dietitian can help protect nutrition while testing a clear hypothesis.

Arrange medical assessment for persistent diarrhoea, repeated vomiting, blood in the stool, unexplained weight loss, fever, night symptoms or signs of dehydration such as very dark urine and dizziness. Seek urgent help for severe abdominal pain, fainting, confusion or trouble breathing. Symptom severity and red flags determine urgency, not the presence of an IgG result.

Ask which diagnosis best fits your symptom pattern, whether any tests should be completed before changing your diet, how long a food trial should last, and how foods should be reintroduced safely.