What is lactose intolerance?
Lactose intolerance happens when your child’s body can’t break down a sugar called lactose because your child doesn’t have enough lactase enzymes.
Lactose is present in all breastmilk, dairy milk and other dairy products. It makes up around 7% of breastmilk and infant formula.
Causes of lactose intolerance
There are three main causes of lactose intolerance.
Lactase non-persistence (hypolactasia)
This happens when your child’s lactase enzymes gradually start to decrease. This is genetic and very common – about 70% of people have this type of lactose intolerance. Symptoms can start to happen after the age of five but are usually more noticeable in teenagers and young adults. Children can usually still tolerate small amounts of lactose in their daily diet.
Congenital lactase deficiency (alactasia)
This happens when babies are born with no lactase enzymes at all. This is genetic but extremely rare. Babies with this kind of lactose intolerance have severe diarrhoea from the first day of life. To thrive, they need a special diet from the time they’re born.
Secondary lactose intolerance
This can happen if a child’s digestive system is upset by tummy bugs like gastroenteritis, which irritates the lining of the stomach and small intestine. This kind of lactose intolerance is short term and usually improves after a few weeks.
Conditions like coeliac disease can also cause secondary lactose intolerance. Once these conditions are being managed properly, lactose intolerance shouldn’t be a problem.
Common symptoms of lactose intolerance
Symptoms of lactose intolerance in children include:
Babies with lactose intolerance might also have symptoms like:
- nappy rash
- trouble settling
- attachment problems during breastfeeding
- failure to gain weight.
Even if your baby has these symptoms, it doesn’t always mean she’s lactose intolerant. Some or all of these symptoms are common in healthy breastfed infants.
If you think your child has the symptoms of lactose intolerance, you should talk with your GP.
Diagnosing lactose intolerance
These are the two main ways to diagnose lactose intolerance:
- Hydrogen breath test: this tests the amount of hydrogen gas in a child’s breath. Lactose-intolerant children have higher levels of hydrogen in their breath.
- Elimination diet: this involves removing foods containing lactose from a child’s diet to see whether symptoms improve. If the symptoms come back once the foods with lactose are reintroduced, lactose intolerance is most likely the cause of the problem.
Because some of the symptoms of lactose intolerance and food allergy are similar, diagnosing lactose intolerance can sometimes be tricky.
Treatment: lactose intolerance in babies
The treatment for lactose intolerance in babies often depends on the cause. And no matter what’s causing your baby’s lactose intolerance, it’s important to soothe and comfort your baby when he’s showing symptoms.
Secondary lactose intolerance
For a breastfed baby with secondary lactose intolerance caused by gastroenteritis, you should be able to continue breastfeeding.
Weaning isn’t usually recommended because breastmilk has so many nutritional benefits and lactose is good for your baby’s growth. Your child can usually tolerate a small amount of lactose, and gradually increasing it can help her body produce more lactase.
If your baby is formula fed or you’re considering giving him formula, consult your GP or a dietitian before using or changing to a low-lactose or lactose-free infant formula. If your child is under six months, avoid using soy-based infant formula.
Treatment and management: lactose intolerance in older children and teenagers
If your older or teenage child is diagnosed with lactose intolerance, you can reduce the amount of lactose in her diet. But you don’t need to get rid of products with lactose completely, especially if your child eats only small amounts of them with other foods during the day.
The following food and diet tips can help.
These foods are OK:
- cheeses with very small lactose content – brie, camembert, cheddar, colby, edam, fetta, gouda, havarti, mozzarella, parmesan, Swiss and Tilstat
- yoghurt – the bacteria in yoghurt breaks down the lactose so it’s usually fine for your child to eat
- calcium-fortified soy products – soy yoghurt, soy milk, soy ice-cream and soy cheese
- lactose-free cow’s milk
- butter and cream – these contain only small amounts of lactose and are usually fine to eat
- bread, cereals, fruit, vegetables, meat and other protein foods
- full-fat milk – the fat in full-fat milk gives your child’s body longer to digest lactose.
Watch out for these foods:
- milk ice-cream and milk desserts
- cream cheese, processed cheese and cheese spread
- muesli bars
- instant mashed potato and vegetables with added milk or white sauces.
Check the ingredients in these foods:
- biscuits, cakes and cake mixes
- milk chocolate.
Lactose overload in babies
Lactose overload isn’t the same as lactose intolerance – that is, it isn’t a problem with the production of lactase. Rather, lactose overload happens when a baby consumes large amounts of lactose at one time and can’t break it all down.
Lactose overload can happen when:
- mothers have a natural oversupply of breastmilk in their baby’s early weeks
- breastfed babies feed frequently and switch breasts before the breasts have been emptied
- breastfed babies have a pattern of short breastfeeds – sometimes mothers shorten breastfeeds because of problems like sore nipples or mastitis or to comfort babies with colic
- breastfed babies drink more first milk than last milk. The lactose-rich first milk passes through the digestive system faster than the last milk, and there’s not enough time for all the lactose to be broken down
- bottle-fed babies drink a lot of milk (this isn’t common).