What should you know about effects of lactose intolerance?

Lactose is the natural sugar in milk and some dairy products. When the small intestine does not make enough lactase, lactose reaches the bowel without being fully digested. Bacteria then break it down and produce gas, while extra fluid can contribute to loose stools. Symptoms may begin after eating or drinking dairy and can vary with the amount consumed. Lactose intolerance is different from a milk allergy, which can cause immune reactions such as hives, swelling or breathing difficulty.

Keep a food and symptom record rather than removing every dairy food without guidance. Some people tolerate small portions with meals, yoghurt or lower-lactose products. If dairy is reduced, choose suitable calcium and vitamin sources and ask a nutrition professional for help with a balanced plan. A clinician may recommend food intolerance testing or a supervised dietary trial when the pattern is unclear.

Arrange an assessment if diarrhoea, pain or weight loss persists, symptoms wake you at night, or you are avoiding many foods. Seek urgent help for swelling of the lips or tongue, wheezing, trouble breathing, faintness or a rapidly spreading rash after dairy, because these symptoms can indicate an allergic reaction.

Ask whether your symptoms fit lactose intolerance, how to test the pattern safely, which foods need replacing, and how to distinguish intolerance from allergy or another bowel condition.