What should you know about lactose intolerance?

Undigested lactose passes into the colon, where bacteria break it down and create gas. Water may also be drawn into the bowel. This can lead to bloating, abdominal pain, rumbling, flatulence, or diarrhoea after dairy foods. Symptoms vary with the amount consumed and with the type of food.

Lactose intolerance is not the same as a milk allergy. An allergy involves the immune system and can cause hives, swelling, wheezing, or vomiting. A new or severe change in digestion may have another cause, so avoiding dairy indefinitely without advice is not always helpful.

Keep a brief food and symptom record, then discuss it with a clinician or dietitian. Many people tolerate small portions, yoghurt, or hard cheese better than a glass of milk. Lactose-free alternatives or lactase products may help, but check labels and maintain calcium and vitamin intake. Nutrition counselling can prevent unnecessary restriction.

Seek prompt care for blood in the stool, persistent vomiting, severe or worsening abdominal pain, fever, dehydration, unexplained weight loss, or diarrhoea that continues. Get emergency help for facial swelling, breathing difficulty, collapse, or a rapidly spreading rash after dairy, because these can indicate a serious allergic reaction.

Ask whether your pattern fits lactose intolerance or another bowel condition. Discuss whether food intolerance testing is appropriate, which foods can remain in your diet, and how to replace nutrients if dairy is reduced. Bring your symptom record and a list of medicines, supplements, and recent infections.