Home › Health Topics › Nutrition > 

Lactose intolerance in babies

lactose; intolerance; baby; pain; lactase; solid; diet; nutrition; milk; breastmilk; breastfeeding; diarrhoea; free; formula ;

Lactase is an enzyme, or chemical, which the body uses to digest the sugar in milk (lactose). If there is not enough lactase, undigested milk sugar gets into the large bowel and may cause gut pains and diarrhoea. This is called lactose intolerance.

Breastmilk always contains lactose, as does infant formula made from cow's milk (except when the formula is modified so that it has a different sugar).


Lactose 'overload'

Many young breastfed babies who are growing well show signs of lactose 'intolerance' (being more unsettled with lots of watery or frothy poos).

  • The problem is that they are getting too much lactose - an overload of lactose.
  • This can almost always be helped without stopping breast feeding (have a look at Breastfed babies below).
  •  It makes babies uncomfortable, but they still get all the nutrition they need.
  • The lactose in breastmilk is made in the breast, and breastmilk always contains lactose.

Some bottle fed babies also do not fully digest all of the lactose that they get in their milk, and show signs of lactose overload. This can be managed in ways that are below in this topic.

Causes of lactose intolerance

  • It is common for adults and children over 4 or 5 years from many ethnic groups, to be somewhat intolerant of milk because of the lactose in it - they do not have as much of the enzyme (lactase) that breaks down lactose.
    • This is normal in peoples who don't often drink milk after babyhood (eg Asian, Australian Aboriginal) but does not usually affect babies in these groups because their babies have more lactase than older children and adults.
  • Gastro (gastroenteritis, tummy upset, bowel infection, infectious diarrhoea) can damage the lining of the small bowel and cause lactose intolerance for a few weeks after the illness in babies (or at any age.)
  • A severe food or milk allergy may cause lactose intolerance. Have a look at the topic Reactions to food for more about this.
  • Very rarely newborn babies do not make any lactase, and become really sick in the first week of life. They do not grow until lactose is removed from their diet.

What you can do

  • If your older child seems to get loose poos and tummy pains after drinking milk, you will need to see a doctor to be sure of the reason and to get information about ways to give him the foods he needs for healthy growth and development. There is information about this in the topic 'Low lactose diet for children'.  
  • If your young breastfed or bottle fed baby is unsettled with lots of watery or frothy poos, you need to check with your doctor as there could be many reasons for this.
    • It is most likely due to lactose overload.
    • Your doctor may arrange to have some tests done for lactose intolerance. A 'Breath Hydrogen Test' may be carried out. However, they are often positive in healthy young babies so they are not helpful in most cases.

If your doctor does say that your baby probably has'lactose overload or lactose intolerance you need to know that this will not harm your baby as long as she or he is otherwise well and growing normally. It makes babies uncomfortable, but they still get all the nutrition they need.

  • Lactose intolerance does not cause vomiting or eczema.
  • The lactose in breastmilk is made in the breast, and is not affected by the mother's diet.  Breastmilk always contains lactose. Lactose intolerance is not caused by, or made worse by, the mother drinking cow's milk.
  • A severe cow's milk allergy may cause similar symptoms, though, and if this is the cause, sometimes a baby is more settled if the mother avoids all dairy foods.

Breastfed babies

  • It is usually better to keep breastfeeding - feeding the baby with a lactose-free formula is sometimes suggested but it does not always help a baby feel more comfortable and be more settled.
  • You may like to try some settling ideas. See the topic 'Crying baby'.
  • When breastfeeding, make sure your baby finishes the first breast (to try to get more of the fatty milk) before trying her on the other breast, as this often helps. Fat in milk slows down digestion, so more lactose is broken down by the lactase and absorbed.
  • Try to space feeds a little, perhaps aiming for about 3 hours from the start of one feed to the start of the next. If your baby wants a feed during this time, put her back to the 'empty' side.

There is much more information in this topic on the Australian Breastfeeding Association website

You could also have a look at our topic Breastfeeding - too much milk

Bottle fed babies

  • A young, unsettled bottle-fed baby with frothy, watery poos could have a trial of lactose-free cow's milk formula. If there is no improvement, return to your baby's usual formula.
  • While soy infant formulas are lactose free, they are not generally recommended for lactose intolerance. See 'Bottle feeding - soy infant formulas'

References and further reading

Anderson J. 'Lactose intolerance and the breastfed baby' Essence Magazine, Reviewed October 2012. Published by the Australian Breastfeeding Association

Anderson J 'Lactose overload in babies' Published by the Australian Breastfeeding Association (Reviewed May 2016)

National Institute of Diabetes and Digestive and Kidney Diseases (NIH-USA) 

Raising Children Network (Australia) 

back to top

The information on this site should not be used as an alternative to professional care. If you have a particular problem, see a doctor, or ring the Parent Helpline on 1300 364 100 (local call cost from anywhere in South Australia).

This topic may use 'he' and 'she' in turn - please change to suit your child's sex.

Home › Health Topics › Nutrition >