Lactose intolerance in babies

Find out what to look out for if you think your baby is lactose intolerant.

In Newborn

    3-minutes read

    At a glance

    If your baby has a hard time digesting milk it could be lactose intolerance

    Lactose intolerance is a rare genetic condition


    Temporary lactose intolerance in babies is more common and usually passes with time

    Temporary lactose intolerance can show up after a tummy bug

    What is lactose intolerance?

    Some babies can have a hard time digesting lactose – the natural sugar found in milk. This can happen temporarily after they’ve had a tummy infection or if they were born prematurely. This is quite common in young babies and fortunately they usually grow out of it. There isn’t an exact figure for true lactose intolerance in babies but it’s very rare. It’s a genetic condition that can only be passed on if both mum and dad have the gene.

    How do I know if my baby is lactose intolerant?

    Lactose intolerance symptoms in babies are often similar to other feeding problems which can be confusing. Symptoms of lactose intolerance will usually occur within a few hours of feeding. To make things a little clearer here’s what to look out for:

    • diarrhoea

    • wind

    • abdominal bloating and pain

    • discomfort and crying

    • fussiness during feeding

    Woman burping baby

    What causes lactose intolerance in babies?

    Unless there’s a genetic condition passed on by the parents, it’s usually caused when a baby doesn’t have (or doesn’t have enough of) the digestive enzyme ‘lactase’. Lactase is produced in the gut to break down the lactose and make it more digestible. Lactose intolerance can even sometimes appear temporarily, shortly after a tummy bug or a long course of antibiotics.

    Some premature babies may have lactose intolerance where their small intestine hasn’t been able to fully develop before coming into the world. This usually improves with time.

    How can I help my baby?

    If you think your baby is lactose intolerant, or if you’re concerned, always seek the advice of your healthcare professional, such as your GP, health visitor or public health nurse. They may advise you to eliminate lactose from their diet, but you should wait for them to advise this before making any big changes yourself. This is especially important since you want to make sure your baby’s still getting all the nutrients they need for healthy growth and development. For bottle-fed babies, your healthcare professional may advise the use of a lactose-free formula but always check with them first before switching.

    If your baby is breastfed you may be recommended lactase drops to help baby digest the lactose found in breast milk.

    What’s the difference between cows’ milk protein allergy and lactose intolerance

    Cows’ milk protein allergy (CMPA) and lactose intolerance are not related. CMPA is one of the most common food allergies in babies and usually appears before 1 year of age. It is a type of milk allergy where a baby’s immune system responds to the proteins found in cows’ milk, causing the baby to have allergic symptoms such as: skin rashes, eczema, diarrhoea, vomiting and stomach cramps. For more information on CMPA read our article.

    Lactose intolerance does not involve the immune system. Symptoms of both condition can be similar so it is important to get the advice of your GP who can help with the diagnosis.

    Next steps

    If your baby has lactose intolerance it should clear up, but keep an eye on them and if you’re ever concerned speak to your GP, health visitor or a public health nurse. Our Careline team are also able to help. As long as the condition is managed and your baby is monitored, lactose intolerance will not affect their development. In most cases the lactose intolerance may only last 4-6 weeks, so make sure you discuss reintroducing lactose with your healthcare professional.

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