If your baby is diagnosed with cow’s milk allergy, you should always follow the advice of a healthcare professional.

Dietary changes for breastfed babies

When breastfeeding, some of the nutrients from the foods you eat are passed to your baby in breast milk. That means when you eat food that contains dairy, your baby may be exposed to cow’s milk protein. In babies with cow’s milk allergy, this exposure to cow’s milk protein can cause an allergic reaction. But this is not a reason to stop breastfeeding. Breast milk provides the best nutrition for babies. 

If a breast-fed baby is diagnosed with cow’s milk allergy, it may be suggested by a healthcare professional that all dairy products are eliminated from the mother’s diet and that the mother takes daily calcium and vitamin D supplements. Milk and milk products such as yogurt and cheese are obvious sources of dairy to exclude, but other foods like breads, cereals and salad dressings can contain milk too. This means all food labels need to be carefully checked for hidden milk ingredients like casein and whey

If a mum is advised by a healthcare professional to remove dairy from their diet, this might need to be done for 2 weeks or longer to allow time for the baby’s symptoms to settle. After then, it may be recommended that the dairy-free diet continues until the baby is completely weaned off breast milk or until the healthcare professional recommends reintroducing cow’s milk protein into the baby’s diet. 

Dietary changes for formula-fed babies

In formula-fed babies with cow’s milk allergy, it’s the cow’s milk protein in routine formulas that causes the allergic reaction. In this case, healthcare professionals may recommend substituting the baby’s routine formula with a hypoallergenic formula that is specially formulated for the dietary management of babies with cow’s milk allergy. The use of a hypoallergenic formula for cow’s milk allergy may be recommended up to 2 years of age alongside a milk-free weaning diet.

Two types of hypoallergenic formulas that may be recommended for the dietary management of babies with cow’s milk allergy are extensively hydrolysed formulas for mild to moderate cow’s milk allergy and amino acid-based formulas for severe cow’s milk allergy.

Extensively hydrolysed formulas

Proteins are made up of lots of amino acids — like building blocks linked together to form long chains. The immune system of a baby with cow’s milk allergy mistakenly sees some cow’s milk protein chains as harmful and allergic reactions occur. Imagine breaking apart these long protein chains into lots of smaller chains. That’s what the cow’s milk protein in extensively hydrolysed formulas looks like. 

The cow’s milk protein chains in extensively hydrolysed formulas are so thoroughly broken down (known as hydrolysed) that the immune systems of most babies with cow’s milk allergy no longer recognise the milk protein as harmful. These formulas are recommended for the dietary management of babies with mild to moderate cow’s milk allergy. Extensively hydrolysed formulas are suitable for around 90% of babies with cow’s milk allergy.

Amino acid-based formulas

Rarely, a baby with cow’s milk allergy reacts severely to cow’s milk protein and may still have symptoms if prescribed an extensively hydrolysed formula. These babies need a hypoallergenic formula made with the individual building blocks of protein: amino acids. Unlike routine infant formulas in which hundreds of amino acids link to form long chains of cow’s milk protein, or extensively hydrolysed formulas in which fewer amino acids link to form small protein chains, amino acid-based formulas have no cow’s milk protein chains. The proteins in these formulas are in their simplest form and are composed of individual amino acids, the compounds that form proteins. Amino acid-based formulas are also recommended for babies with multiple food allergies and other conditions that require an elemental diet.  

What to expect if a hypoallergenic formula is recommended by a healthcare professional

Due to their special formulation, hypoallergenic formulas for the dietary management of babies with cow’s milk allergy smell and taste different to breast milk, regular infant formulas and cow’s milk. This means it can take some time for babies to become comfortable and familiar with their new diet. As the new diet allows the symptoms to start to resolve, babies should become more settled and their appetite may improve.