What should you know about slight lactose intolerance?

Lactose is the natural sugar in milk. Lactase, an enzyme in the small intestine, breaks it down. When lactase is limited, undigested lactose reaches the colon, where it can draw in water and be fermented by bacteria. This may lead to gas, bloating, cramps or loose stools after dairy.

The amount tolerated differs between people and may vary by food. Hard cheeses and yoghurt can be easier for some people than a large serving of milk. These symptoms do not prove lactose intolerance; infection, coeliac disease, irritable bowel syndrome and other causes can overlap.

Keep a short food-and-symptom diary, noting the dairy type, portion and timing. Try smaller portions with meals rather than removing every dairy food at once. Lactose-free products or lactase products may help some people; follow product directions. Ensure calcium and vitamin D come from suitable foods or supplements, especially if reducing dairy. Nutrition counselling can help make changes balanced and sustainable.

Arrange a review for ongoing diarrhoea, weight loss, blood in stool, nighttime symptoms, persistent abdominal pain, vomiting or symptoms that began suddenly. Seek urgent help for severe pain, dehydration, fainting or an allergic reaction such as swelling or breathing difficulty. Food intolerance testing may be discussed when the history is unclear, but testing should sit alongside a clinical assessment.

Do my symptoms fit lactose intolerance, or should another cause be checked? How can I test tolerance without risking poor nutrition? Would food intolerance testing or nutrition counselling be appropriate for me?