Lactose Intolerance in Babies: What You Need to Know

Lactose intolerant babies may struggle to digest your breast milk, but it's important to understand the different types of lactose intolerance and how it is diagnosed and treated.

Are you concerned your baby may be lactose intolerant? Lactose intolerance is actually quite common among adults and older children. New parents who know the symptoms – or maybe experience lactose intolerance themselves – often wonder if their baby might be lactose intolerant too. Here’s everything you should understand about lactose intolerance, how it is diagnosed, and the best way to treat it in babies if your little one does in fact have this condition confirmed by their pediatrician or healthcare provider. 

What is Lactose Intolerance?

Lactose intolerance is an inability to digest lactose, a milk sugar. All milk contains lactose, including cow milk and human breast milk. Our bodies produce an enzyme called lactase, which breaks lactose into smaller sugars called glucose and galactose, which are then absorbed into the gut.

If a baby does not produce enough lactase, the lactose is not broken down and cannot be digested. It stays in the intestine, where it can cause diarrhea and other hallmark symptoms of lactose intolerance.

Symptoms of Lactose Intolerance in Babies

Some of the most common lactose intolerance symptoms include:

  • Excess gas
  • Nausea
  • Abdominal pain
  • Bloating
  • Diarrhea and liquid stools

Is Lactose Intolerance the Same as a Milk Allergy?

Lactose intolerance is not a milk allergy. In fact, these are actually two different conditions. Lactose intolerance is a digestive issue caused by an inability to digest lactose. Milk allergies, in contrast, occur when a baby’s immune system reacts to a substance in the milk and causes an allergic inflammation. Lactose intolerance may be uncomfortable and even painful for a baby, but it cannot result in life-threatening anaphylaxis like an allergy can.

Can Babies Be Lactose Intolerant?

Babies can be lactose intolerant, but it is rare and, in most babies, a temporary case that often resolves in time and on its own. There are two primary causes of lactose intolerance in babies:

  • Secondary lactose intolerance: This means that your baby can produce lactose, but a separate illness or allergy has damaged the gut lining and temporarily prevented lactose production. This type of intolerance only lasts until your baby’s gut heals.
  • Congenital lactose deficiency: This is a genetic condition in which a baby cannot digest lactose. This is an extremely rare condition that often results in severe diarrhea from birth.

Premature babies are more likely to be lactose intolerant. However, most premature babies can digest lactose, and those that are lactose intolerant at birth usually develop the ability to digest lactose soon after.

Diagnosing Lactose Intolerance

Your pediatrician may diagnose lactose intolerance in your little one with a hydrogen breath test. This is done because lactose intolerant children have more hydrogen in their breath. They may also request a stool sample from your little one to check for acid or glucose in the stool, which could indicate the presence of undigested glucose.

Depending on how your baby is fed, lactose intolerance may be diagnosed with an elimination diet. For exclusively breastfed babies, you can start by removing lactose from your own diet – things like milk, cheese, butter, yogurt, and even some chocolate.

Treating Lactose Intolerance in Babies

Medical professionals usually advise breastfeeding mothers to continue feeding their baby with breast milk, even if your little one is diagnosed with secondary lactose deficiency (which is by far the most common type of lactose intolerance in babies). Weaning is not recommended because the benefits of breast milk are important at this age. Your milk has valuable nutrients just for your little one and consuming it can help him or her produce more lactase. 

Conversely, babies with congenital lactose deficiencies require a special diet and treatment plan guided by a pediatrician. Though much rarer, partnering with your pediatrician can help you and your little one work through this based on your family’s unique needs and situation.

Breastfeeding Guidance for New Moms

Remember, mama, parenthood isn’t always for the faint of heart! Though there may be challenges along the way, Medela is here for you through every step of your prenatal and breastfeeding journey. Consult one-on-one via e-mail with our board-certified lactation consultants, who can help answer your breastfeeding questions, or sign up for Medela Family to unlock a world of breastfeeding support right to your Inbox today.

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