Lactose intolerance is a common digestive condition where the body has difficulty digesting lactose, a sugar found in milk and dairy foods. It occurs when there isn’t enough of the enzyme lactase in the small intestine to break down.1
People with lactose intolerance may experience gastrointestinal symptoms after eating or drinking dairy. Symptoms can include bloating, stomach cramps, gas and diarrhoea and usually occur directly after eating.2
Most people can break down lactose but It’s normal to make less lactase as you age.2
Lactose Intolerance as you Age
It’s normal to lose lactase as you age, so it’s important to make sure you’re getting adequate nutrition to compensate for any protein, calories, vitamins and minerals lost.
Lactose Intolerance: Symptoms, Causes & Dietary Management
Why Does Lactose Intolerance Occur?
Lactose is the primary sugar in dairy products. To digest it properly, the body needs lactase, produced in the small intestine. When lactase levels are low, lactose passes into the large intestine undigested. Gut bacteria then ferment it, which produces gas and discomfort.3
Key Causes of Lactose Intolerance1
● Primary lactose intolerance: a genetic decrease in lactase production over time.
● Temporary intolerance: after gastroenteritis or intestinal inflammation.
● Secondary intolerance: due to gut conditions (like Coeliac disease) affecting lactase production.
Lactose intolerance is not the same as a dairy allergy, which involves the immune system reacting to dairy proteins.6
Common Symptoms of Lactose Intolerance
People can experience different symptoms depending on how much lactose is eaten and/how sensitive a person is. Common symptoms include: 1
● Abdominal pain and cramps
● Bloating and flatulence
● Diarrhoea or loose stools
● Nausea in some cases
Symptoms usually begin within a couple of hours after consuming high-lactose foods.
If you’re experiencing these symptoms, please seek advice from your medical professional.
How is Lactose Intolerance Diagnosed?
Diagnosis may involve:1
● Symptom tracking after dairy consumption
● Hydrogen breath test to measure lactose digestion
● Medical evaluation to rule out other causes like IBS or coeliac disease
It’s best to speak with a GP or Accredited Practising Dietitian (APD) to confirm lactose intolerance and tailor dietary changes.
Dietary Management: What You Can Eat?
It’s important to note that you don’t need to cut out dairy completely. Many people with lactose intolerance can still enjoy dairy in ways that reduce symptoms.
Tips to Enjoy Dairy With Less Discomfort
1. Adjust Serving Sizes1
Drink milk in small amounts (e.g. half a cup) instead of large servings. Consuming dairy with other foods can slow digestion and reduce symptoms.
2. Choose Lower-Lactose Foods3
● Yoghurt: fermented bacteria help break down lactose
● Hard cheeses (e.g., cheddar, Parmesan): naturally low in lactose
● Butter: very low in lactose
3. Try Lactose-Free Alternatives1
Lactose-free milk, yoghurt and cheese have lactase added, making them easier to digest.
4. Use Lactase Enzyme Supplements1
Over-the-counter lactase tablets or drops can help digest lactose when taken with dairy foods.
5. Explore Dairy-Free Milks1
Plant-based milks like soy, oat or almond are naturally lactose-free. Check labels for added calcium.
Nutritional Considerations
Dairy products are important sources of calcium, protein and vitamin D. If you reduce lactose foods, ensure you get adequate nutrients from other sources or fortified alternatives.1
Oral Nutritional Supplements (ONS) like Ensure* can be used to meet the daily requirements of protein, calories, vitamins and minerals. Ensure* are categorised as low lactose†† in accordance with FSANZ guidelines.7
Frequently Asked Questions about Lactose Intolerance
Is lactose intolerance permanent?
Can I still drink milk if I’m lactose intolerant?
Yes, many people tolerate small amounts of milk, especially when consumed with food or as lactose-free milk.4
Is lactose intolerance common?
Yes, in Australia 1 in 4 people suffer from lactose intolerance or sensitivity or live with someone who does. 6
How is lactose intolerance different from a milk allergy?
Lactose intolerance is a digestive issue due to low lactase. A milk allergy is an immune reaction to proteins in dairy.4
* Ensure® is a food for special medical purposes. Use only under medical Supervision.
††Low lactose refers to the product containing no more than 2 g of lactose per 100g.
References
1: Dietitians Australia, Lactose intolerance, https://dietitiansaustralia.org.au/healthadvice/lactose-intolerance, Accessed Jan 2026
2: Health Direct, Lactose Intolerance, https://www.healthdirect.gov.au/lactose-intolerance, Accessed Jan 2026
3: Better Health, Lactose Intolerance, https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/lactose-intolerance, Accessed Jan 2026
4: Dairy Australia, https://www.dairy.com.au/health-and-nutrition/dairy-and-wellness/lactose-intolerance, Accessed Jan 2026
5: NHS Inform, https://www.nhsinform.scot/illnesses-and-conditions/nutritional/lactose-intolerance/#:~:text=Depending%20on%20the%20underlying%20reason,last%20for%20a% 20few%20weeks, Accessed Jan 2026
6: Food Allergy Research & Information, https://www.foodallergy.org/resources/milk-allergy-vs-lactose-intolerance, Accessed Jan 2026
7: Australia and New Zealand Food Standards Code. Standard 2.9.5 – Food for special medical purposes.
