Lactose Intolerance

Difficulty digesting lactose, the sugar in milk, causing bloating, gas and diarrhoea after dairy foods.

DigestionLast updated: 21 October 2026

Quick Summary

Primary Symptoms

Bloating, wind, tummy cramps, diarrhoea and nausea from 30 minutes to a few hours after milk or dairy.

Common Treatments

Reducing or spacing out dairy, choosing curd or lactose-free milk, and lactase supplements.

Risk Factors

Common in adults of Asian and African background; also after gut infections or bowel diseases.

OverviewSymptomsCausesTreatmentFAQ

Overview

The body needs an enzyme called lactase to digest lactose. Many adults make less lactase as they get older.

Most people can still have small amounts of dairy, and curd (yoghurt) and hard cheese are often tolerated better than milk.

Symptoms

Bloating and gas

After milk or dairy.

Tummy cramps

And rumbling.

Diarrhoea

Loose stools.

Nausea

Sometimes.

Causes & Risk Factors

Biological Causes

Low levels of the lactase enzyme in the small intestine.

Key Risk Factors

  • Genes and ethnicity Very common in South Asian adults.
  • Gut damage After infections or in coeliac or Crohn's disease.
  • Age Lactase levels fall after childhood.

Management & Treatment

01. Adjust dairy

Smaller amounts spread through the day, with other food.

02. Alternatives

Curd, lactose-free milk and fortified plant milks.

03. Calcium

Make sure you get enough calcium from other foods.

Frequently Asked Questions

Is it the same as a milk allergy?
No. An allergy involves the immune system and can be dangerous.
Do I need to avoid all dairy?
Usually not.

Sources and further reading

Last updated 21 October 2026. For more detail, see these trusted health organisations.