When you first had your baby, you didn’t run into any problems regarding breastfeeding. She latched on easily, fed for a decent amount of time, and always seemed satisfied and content after a feed. You never worried that she wasn’t getting enough milk or that the milk wasn’t giving her all the nutrients she needed.

However, since you moved onto formula feeding, you’ve started noticing that your little one has a bit of an upset stomach, which is always aggravated by the feed. You wonder - Does this have anything to do with the cow’s milk in the formula?

Many parents run into issues when it comes to feeding their babies formula, so don’t feel that you’re alone in this struggle. If your baby is reacting badly to the cow’s milk in the formula you are feeding them, then it’s possible they could either have a cow’s milk protein allergy (CMPA) or a cow’s milk intolerance. For your information, the two are completely unrelated.

To determine whether your baby needs lactose-free milk, let’s first outline the difference between cow’s milk protein allergy and lactose intolerance:

What is the difference between cow’s milk protein allergy and lactose intolerance?

Cow’s milk protein allergy (CMPA) This is when a baby’s immune system reacts to the proteins found within cow’s milk. This is an extremely widespread allergy. It is also more likely to affect babies that suffer from eczema.

Lactose intolerance If a baby is lactose intolerant, they have trouble digesting lactose, a natural sugar that can be found within milk. Lactose intolerance can last for around 4 weeks, by which point the gut starts to recover and break down lactose once again. Lactose intolerance can occur after a stomach infection.

Now that you know the basic difference between cow’s milk protein allergy and lactose intolerance, it’s time to ascertain whether your baby is most probably suffering from a CMPA or a lactose intolerance. This is how you will know what milk to feed them.

How will I know whether my baby has CMPA or an intolerance to lactose?

In order to know what milk you should feed your baby, it’s best to outline the difference between CMPA and lactose intolerance and how the conditions generally affect babies differently.

CMPA: If your baby has CMPA, they will be allergic to one or both of the proteins the milk contains; casein and whey. While casein is the curd formed when the milk turns sour, whey is the watery part left over after the curd is removed.

Symptoms of CMPA: If your baby has CMPA, they will likely have symptoms similar to colic. They will probably have an immediate reaction after drinking or eating something that contains the proteins within the food or drink that contains the proteins. They might have watery eyes, a stuffy nose, their face will flush, and a rash will appear. They might also have symptoms of diarrhoea or, in rare cases, a severe reaction called anaphylaxis.

What does the doctor recommend if my baby has CMPA? If your baby has CMPA, then your doctor will likely recommend a special hypoallergenic formula. The formula will probably be a fully hydrolysed formula or acid-based milk.

Will my baby grow out of CMPA? Although it’s natural to worry that your baby will have CMPA forever, babies usually outgrow their allergy by the time they are 3 years old. However, this doesn’t mean your baby won’t develop an allergy to something else, as between half and 80 per cent of children who have reacted to milk as babies will develop asthma.

Lactose intolerance: If your baby has a lactose intolerance, they will most probably lack the enzyme lactase. This enzyme is necessary to break down lactose.

Symptoms of lactose intolerance: If your baby has lactose intolerance, they might experience symptoms such as irritability, bulky, frothy and watery faeces, pain and swelling in the tummy, and failure to gain weight.

What does the doctor recommend if my baby has lactose intolerance? Treatment by a doctor in terms of milk will depend on the extent of your baby’s intolerance. You’ll be able to talk through in more detail with your paediatrician.

Does my baby need lactose-free milk?

The naturally occurring sugar isn't for everyone, explains Unii.