Why is my baby reacting to his formula?

Reading time: 8 min

If your baby is fussy and you suspect it may be formula related, you just might be right.

Before you start jumping between brands, or feeding soy formulas one day and cow’s milk the next, let’s try to think through this conundrum logically and systematically, together. It gets rather fiddly, so stay with us.

What’s in formula that my baby may react to?

Most baby formulas are made from a blend of cow’s milk and other ingredients. Milk contains two proteins that are potentially allergenic: whey and casein. Both proteins are present in human breast milk too but in different forms, which is why your baby may develop symptoms if you’ve been breastfeeding and are weaning your baby onto formula milk. Formula milk (and breast milk) also contain lactose, a type of sugar. Lastly, some formulas use soy as an alternative to cow’s milk. Soy is also a known allergen.

But first, what is an allergy and what is a food intolerance, and what is the difference?

Food intolerance vs. food allergy

A food allergy is an abnormal reaction to a foodstuff. Your immune system mistakes allergens for foreign invaders and mounts a response to them, leading to reactions such as skin rashes, nausea, vomiting, diarrhoea, pain, problems breathing, and others.

In a classic type 1 or immunological allergy, your body makes immunoglobulin E (IgE) antibodies in response to the allergen. A true cow’s milk protein allergy (CMPA) involves IgE antibodies, and soya can also cause this type of allergy.

If you have this type of allergy, you’ll know all about it straight away, says Dr Peter Barrow, a gastroenterologist at the Donald Gordon Medical Centre in Johannesburg with an interest in paediatrics. “With a type 1 allergy, you have an immediate response after eating certain foods: your face swells up, you develop a rash, you cannot breathe – you may have an anaphylactic reaction and need to be rushed to hospital. If you suspect that your child has a type 1 sensitivity to a food, it is luckily very easily tested and managed.”

There are other reactions that do not involve IgE antibodies being produced. Type 2 to type 4 allergies fall under this umbrella, and the body’s reactions are usually slower and less severe, and include digestive issues, respiratory issues, arthritis and eczema.

“Unfortunately, there is no good test for this type of allergy,” says Dr Barrow. “Antibody tests are nothing more than a glorified food diary,” he says, because all people will produce antibodies to all foodstuffs to which they have been exposed. “If you have been exposed to, say, bananas, then the antibody test will indicate this, but that does not mean to say there’s an allergy, or a negative reaction, there. The kit has simply recorded your exposure to bananas.”

“The only reliable diagnostic tool is an elimination test,” says Dr Barrow. “If you suspect a food is causing symptoms in your child, eliminate it from his diet, and then challenge the body with the food again in a few weeks’ time. If there is a reaction, you know which food to avoid for now. Luckily, many children outgrow these allergies over time.”

Lactose intolerance is another matter entirely. It’s not an allergy; it happens when you can’t properly digest the lactose in milk. “Lactose intolerance means you don’t have enough of the enzyme lactase,” says Dr Barrow, “and the condition is usually genetic. For example, 90% of Chinese people don’t produce lactase (and traditionally there is no dairy in a Chinese diet). For Europeans, the prevalence is about 10%.”

“The sugar in the milk gets to the gut and the bacteria in the large colon ferment the lactose and produce gas, which can be painful. The lactose itself can act as a laxative, so it can cause diarrhoea, pain and bloating,” he adds.

Most people’s production of lactase naturally drops off after the age of about four years, the time when early humans would probably have stopped breastfeeding (and before early humans started to drink the milk of other mammals).

“A food allergy is an abnormal reaction to a foodstuff […] Lactose intolerance is another matter entirely. It’s not an allergy; it happens when you can’t properly digest the lactose in milk.”

But very rarely, young babies can show symptoms of lactose intolerance. Premature babies may struggle with discomfort as their bodies catch up with making lactase, and babies who have been sick with diarrhoea may have dropped their lactase production for a short while. Babies with diseases such as coeliac disease or Crohn’s disease would also battle. Luckily, there are lactose-free formulas available, even ones you can use for a short while if your baby’s been sick, for example.

Symptoms of food allergies or intolerances

Nobody wants to see their precious baby suffer needlessly! If your baby seems to have discomfort after feeding, including colic, cramping, pulling up legs, spitting up, crying and diarrhoea, bleeding from the rectum, or constipation, take them to the doctor for an IgE test. If that’s negative, it’s worth doing the elimination diet to see if whey, casein, lactose or soy may be the culprit.

This sounds exactly like my baby! What do I feed him now?

The good news is you have options. The bad news is they tend to be expensive.

  • Lactose-free: For suspected lactose intolerance, start with a lactose-free formula such as Novalac Allernova Smooth, Novalac Aminova, Nan Lactose-Free Stage 1 or S26 Lactose-Free. Novalac’s unique selling point is that you can choose how many feeds of lactose-free formula to give your baby, according to his needs and what he can tolerate, and you can happily alternate between Novalac Allernova Smooth and Novalac 1 without harming your baby.
  • Reduced lactose: It may work for your baby just to reduce the amount of lactose he is exposed to. Novalac AC (Anti-Colic) contains less lactose, so you can see if your baby can cope with a reduced amount.
  • Extensively hydrolysed: If you suspect the problem lies with the casein or whey, there are extensively hydrolysed formulas on the market, where the protein chains have been treated to be much shorter and easier to digest. These formulas are called hypoallergenic (this means they do not cause a reaction in 90% of allergic infants, and there are strict guidelines on what formulas are allowed to call themselves hypoallergenic). Novalac Allernova Smooth, Similac Alimentum, Nutricia Pepticate and Nestlé Alfaré are South African products on the market.
  • Amino acid based: For the 10% of allergic infants who still react to extensively hydrolysed formula, amino acid-based formula is the final feeding option (other than breastfeeding with diet restriction for the mother). Amino acids are the building blocks of proteins. Infants with a proven severe cow’s milk protein allergy (CMPA) should proceed directly to amino acid formula, according to the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN). Novalac’s Aminova, Nutricia Neocate and Nestlé Alfamino are options.
  • Partially hydrolysed: Babies who have used extensively hydrolysed or amino acid formulas successfully, whose symptoms have cleared up, can now be challenged with a partially hydrolysed formula. That’s why this option, counterintuitively, comes after the extensively hydrolysed formula. Novalac HA is for babies at risk of developing allergies. It is made from partially hydrolysed whey proteins (which digest faster) and contains no casein (which takes longer to digest).
  • Soy-based formula: If your baby has a proven very severe cow’s milk allergy even against extensively hydrolysed formula, or if your family has a religious or ethical objection to cow’s milk, you may choose a soy formula, although the recommendation is that this be from the age of six months only, and only if your baby seems to tolerate soy formula better than cow’s milk formula, and if you can’t afford the extensively hydrolysed formulas. This is because soy is not good at preventing allergies – it is, in fact, an allergen. There is no evidence that soy formulas help prevent colic or reflux. There has been controversy in past years about other ingredients in soy, none have been proven to be harmful.

You can find a discussion on elimination diets by the renowned paediatric dietitian Alison Lang and others in the South African Medical Journal online.

Disclaimer: This is not a sponsored post and is based on personal experience and personal brand preference of the content author. BabyYumYum reserves the right to its opinions and fully supports the notion of promotion that breast is best in line with the World Health Organisation (WHO) infant feeding guidelines. Breast milk is the best food for infants. Good maternal nutrition is essential to prepare and maintain breastfeeding. If breastfeeding is not applied, an infant formula may be used according to the advice of health professionals. Preparation and storage of any infant formula should be performed as directed on the tin in order not to pose any health hazards.