Several mechanisms can produce similar symptoms
IBS involves recurring abdominal pain with changes in bowel habits. The gut may be more sensitive to stretching, and communication between the gut and brain can influence symptoms. Symptoms are real even when routine tests are normal.
The microbiome is an active research area, but an unusual microbiome result does not by itself establish the cause of an individual’s symptoms. Stress can affect symptoms without being the whole explanation.
How is IBS diagnosed?
A clinician reviews the pattern and duration of symptoms, medicines, medical history and any warning signs. IBS can often be diagnosed from symptoms and a targeted assessment. Not everyone needs colonoscopy or extensive testing.
Depending on the presentation, other conditions such as coeliac disease or inflammatory bowel disease may need assessment. Do not start a gluten-free diet before a planned coeliac assessment without asking your clinician, because the diet can affect test results.
IBS, SIBO and food reactions
SIBO and IBS are different concepts, although symptoms can overlap. Breath testing may be appropriate after an individual assessment; results require interpretation alongside symptoms and test limitations. A SIBO test does not automatically establish the cause of IBS.
Lactose and other fermentable carbohydrates can worsen symptoms for some people. Food intolerance is different from allergy. Broad commercial food-reaction tests cannot independently establish which foods cause IBS. Avoid prolonged, extensive restriction without appropriate support.
What may help, and when should you seek care?
Management depends on symptoms and may include dietary changes, a dietitian’s support, medicines and gut–brain therapies. The aim is to improve symptoms and daily life, rather than promise a particular biological explanation or cure.
Blood in the stool, unintended weight loss or new and worsening symptoms need medical assessment. Sudden severe abdominal pain or marked illness needs urgent care. A consultation can review previous investigations and identify appropriate next steps.
Sources and further reading
This is general information and does not replace an individual medical assessment.
