Lactose Intolerance in Babies

Lactose is an important source of carbohydrates for babies and is found in all forms of milk, including breast milk, formula milk and animal milk. When a baby cannot digest the lactose, it is described as ‘lactose intolerance’. Lactose intolerance in babies can cause discomfort, but symptoms can usually be resolved by removing lactose from your baby’s diet.

If you suspect your baby may have lactose intolerance, it's important to see your GP as soon as possible, to rule out anything else that might be causing the symptoms. Your GP may take a medical history, look at how well your baby has been growing and make a note of any symptoms you've noticed. They might also ask you to trial your little one with lactose-free baby milk. Additionally, when it’s time to start weaning your baby, avoiding foods with lactose may be important to trial. This is called an elimination diet. If the symptoms reduce or go away, your GP may ask you to continue your baby with this lactose-free diet.

An allergy involves the body reacting to a protein (such as in milk) with an immune response and is different to an intolerance which causes uncomfortable symptoms. Lactose is not a protein and so it is not possible to be allergic to lactose.

Our bodies produce an enzyme called lactase which breaks down lactose in food to convert into energy. A lactose intolerance is caused by not having enough, or any, lactase. This means the lactose cannot be properly digested and causes uncomfortable symptoms.

Signs of lactose intolerance in babies can vary, but you might notice any of the following:

These symptoms might occur anywhere from within a few minutes to a few hours of having milk or milk products. Lactose intolerance symptoms in babies are general, making them hard to spot, especially in a young baby.

There are four different types of lactose intolerance:

If your baby is diagnosed with lactose intolerance, you'll need to avoid lactose, in milk and foods. For very young babies, this will involve switching to a lactose-free formula milk for babies and weaning diet. Your baby may also need additional calcium, magnesium and zinc to replace what they aren’t getting from milk.

For older babies, you may need to swap from a lactose-free formula to a lactose-free milk (found in most supermarkets), and check ingredients labels on other foods carefully to make sure they don't contain lactose. Look for the word ‘milk’ in bold within the ingredients list.

With primary lactose intolerance, toddlers can sometimes tolerate small amounts of foods with lactose, such as cheese and yoghurt. In this case, your GP or dietitian can advise you. Both the NHS and HSE websites have more information about lactose intolerance.

This can all sound a bit daunting, but there's a silver lining: removing the lactose usually resolves the symptoms, which leads to a healthier, happier baby. Additionally, Lactose intolerance baby formula can be found in many supermarkets, making it easier to eliminate lactose from your child’s diet.

The benefits of switching to a lactose-free formula are a reduction of symptoms for your baby, such as relieving diarrhea or preventing the baby from becoming dehydrated. Your baby may become more settled at feeding times as they’re able to digest their feeds better. Symptoms should also improve quite quickly (within 2-3 days) once you switch to lactose-free.

There are some downsides of lactose-free formulas such as availability. It may be harder to find pre-made lactose-free formulas if you’re away from home, or dairy-free options if you follow a vegan diet. This means that you may need to be extra prepared when taking trips away with your baby.

The other downside is the potential for some nutritional deficiencies. If your baby is low in zinc or iron, this can be given as a supplement and you can speak to your GP, or dietician, about selecting the right lactose intolerance milk for baby.

If you think your baby might be lactose intolerant, make an appointment with your GP who will be able to advise on next steps for your and your baby. There are many lactose-free options available, making lactose-free life more straightforward than ever.

Lactose intolerance can be overwhelming for parents and caregivers, but the good news is that it is treatable. Keep a close eye on your baby’s behaviours around feeding times as well as their wind and faeces. If you are concerned that your baby might be intolerant to lactose, always discuss with your GP.

How can I tell if my baby is lactose intolerant?

Identifying lactose intolerance can be challenging in babies, as the symptoms can overlap with other conditions such as colic or reflux. It is suggested to monitor your baby’s feeding patterns, what their faeces look like, and overall behaviour after feeding. If you are concerned about symptoms, speak with your GP.

What does lactose intolerant poop look like?

Babies with lactose intolerance may have faeces that are loose and watery, and may look green or yellow. Faeces may also look bulky or frothy.

Can lactose intolerance cause acid reflux in babies?

Reflux and vomiting can occur in lactose intolerant babies. While acid reflux is not directly caused by the lactose intolerance, the other symptoms such as digestive bloating can cause reflux or make reflux worse.

What happens if you ignore lactose intolerance in babies?

Ignoring symptoms of lactose intolerance is not recommended as it can cause some health issues such as dehydration, failure to gain weight and ongoing discomfort and irritability. It is

suggested to speak to your GP if you are concerned about symptoms of lactose intolerance.

What is the difference between lactose intolerance and milk allergy in babies?

A milk allergy involves an immune response to the protein in milk, whilst lactose intolerance is caused by the body not being able to break down the lactose found in milk and digest it properly.