Written and reviewed by Dr Ali Zad, FRACP gastroenterologist, Brisbane. Last reviewed November 2026 against current Australian and international guidelines. General information only, not a substitute for personal medical advice.
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What is lactose intolerance?
Lactose intolerance means the body does not make enough lactase, the enzyme that digests the sugar in milk. It can cause bloating, wind, cramps and diarrhoea after dairy. Most people can still manage small amounts, and lactose-free products are widely available. Testing options, including breath tests and biopsies at gastroscopy, are explained under lactase, sucrase and maltase deficiency.
Is a food intolerance the same as a food allergy?
No. A food allergy involves the immune system and can cause hives, swelling or anaphylaxis. A food intolerance causes digestive symptoms such as bloating or diarrhoea and is not dangerous, although it can be very uncomfortable.
What is SIBO?
Small intestinal bacterial overgrowth (SIBO) occurs when excess bacteria grow in the small intestine, causing bloating, wind, diarrhoea and sometimes poor absorption of nutrients. It is more likely after certain bowel surgery, with slow gut movement or with some medical conditions. Breath testing can help diagnosis, and it is treated with antibiotics.
How is SIBO treated?
SIBO is usually treated with a course of antibiotics, most often rifaximin. Treating the underlying cause, such as slow gut movement or certain medicines, helps prevent it coming back. Dietary changes may help with symptoms.
What is fructose malabsorption?
Some people do not absorb fructose well, a sugar found in fruit, honey and some sweeteners. Unabsorbed fructose ferments in the bowel and can cause bloating, wind and diarrhoea. It is managed by reducing high-fructose foods, often as part of a low FODMAP approach.
Should I go gluten-free if I feel better without wheat?
Please be tested for coeliac disease before cutting out gluten, because a gluten-free diet can make coeliac tests falsely normal. Some people without coeliac disease feel better with less wheat because of its FODMAP content rather than gluten.
Are food intolerance tests from pharmacies or online reliable?
IgG food intolerance blood tests and hair or bioresonance tests are not scientifically validated and are not recommended. Breath tests and supervised elimination and reintroduction diets with a dietitian are more reliable ways to identify triggers.
Related procedures and information
Book an appointment
If you have symptoms of food intolerances and sibo, see your GP or book a consultation with gastroenterologist Dr Ali Zad on (07) 2111 2600 or request an appointment online. You can book directly; a GP referral is needed for a Medicare rebate.
Dr Zad consults and performs procedures across Brisbane and Moreton Bay: Brisbane City and Spring Hill, North Lakes, Caboolture, Everton Park, Taringa and Redcliffe and Kippa-Ring.
