• Nutrition & health

Lactose Intolerance: What is it?

By Joanna Koat

Joanna is a Nutrition & Regulatory Lead at Fonterra and holds a Masters of Dairy Science & Technology.

  • Nutrition & health

While milk, yoghurt and cheese products are generally recognised as nutritious food choices, not everyone can always enjoy what dairy has to offer.

Some people have an allergy to cow’s milk protein and have to avoid dairy products completely, but for those with lactose intolerance, dairy isn’t necessarily off the cards!

So what is lactose intolerance, how do you know if you have it, and which dairy products can you still consider consuming?

"For those with lactose intolerance, dairy isn’t necessarily off the cards!"

What is lactose intolerance?

Lactose is the naturally occurring sugar in cow’s milk. When consumed, lactose is digested and broken down into smaller units by an enzyme called lactase, before it is absorbed in the body. Lactose intolerance can occur when we consume more lactose than our body can digest.  Common symptoms of lactose intolerance include bloating, flatulence, diarrhoea and stomach cramps – usually within 30 minutes – two hours of consuming food or drink that contains lactose. 

How common is lactose intolerance?

Lactose intolerance is not as common as you might think because there are a number of gut disorders that have similar symptoms to lactose intolerance, such as irritable bowel syndrome (IBS) or gluten intolerance.  In fact, experts say that the majority of people who think they are lactose intolerant actually might not be.

Lactose intolerance also differs considerably to a cow’s milk protein allergy - which is a far more serious condition and occurs when the immune system reacts to the protein in milk. Reactions to cow’s milk protein can include swelling of the lips, face or eyes, hives or welts, tingling of the mouth, wheezing, eczema or anaphylactic shock and all products containing dairy need to be avoided.

How do I know if I have lactose intolerance?

It’s important to visit your GP to correctly diagnose digestive issues and avoid unnecessary dietary restrictions. Before visiting your GP, keep a diary of what you eat and drink, and record symptoms you experience. Your GP may suggest removing lactose from your diet for a week or two to see if this relieves symptoms. Further testing may be recommended by your GP to confirm if you have lactose intolerance. This can include a hydrogen breath test or a lactose tolerance test. 

What dairy products can I still consider?

While those with cow’s milk protein allergy should not eat any products containing dairy, this is not the case for those with lactose intolerance. If you have lactose intolerance, reducing your lactose intake, rather than avoiding it completely, is recommended. In fact, completely eliminating lactose from the diet can actually worsen the symptoms when lactose is consumed. Dairy is a source of essential nutrients, including protein, calcium, B vitamins, phosphorus and potassium and unnecessary restriction can lead to a lack of certain nutrients that are important for good health unless an effort is made to get them from other foods.

Most people with lactose intolerance can still eat some dairy products and many can have up to a glass of milk every day, particularly if spread out over the day and consumed with meals. Most hard cheeses are low in lactose e.g. Cheddar, Colby, and Edam. Due to their lactose fermenting cultures, yoghurts can help further aid lactose digestion within the gastrointestinal tract so also tend to be well tolerated. There are also low or zero lactose milks available which have been treated with the enzyme lactase to break down the lactose. If you think you might have lactose intolerance, see your health professional for a proper diagnosis and dietary advice tailored to your individual needs. Lactase tablets can help the body better digest lactose, your health professional can advise if this is suitable for you.

Higher lactose products*
Low lactose products
Hard cheese 
A glass of milk
Lactose free dairy products 
Soft cheeses


*These products may still be tolerated if spread throughout the day with meals and/or taking lactase tablets as directed by your health professional. Consult your health professional for more information.