When the Health Ministry confirmed definite allergies to GOS in infant formula recently, we hunted out an allergy specialist to talk to us about them…


The headlines were scary: Milk products! Allergies! Oh no… Everyone promptly raced home or to the kitchen or supermarket and tried to find out what milk powders had this GOS stuff in it. What happens if it’s in your baby’s formula?

A quick check of the infant-formula shelves in local supermarkets didn’t help: Half of them listed galactooligosaccharides (or GOS) in them. And reading the Internet was even more confusing as it stated that normal cow’s milk already had GOS in it naturally. The MOH/AVA statement emphasised that the GOS allergy was a) rare (two confirmed cases since 2007) b) had not so far been identified in babies and c) was found in people who had pre-existing asthma, eczema and such problems. But parents were still twitchy.

We put the questions about this additive, to Dr Lee Bee Wah, a paediatrician practising in Mount Elizabeth:

1) What is GOS?
Galactooligosaccharides (or GOS) are short chains of glucose and…galactose (found in milk). It is a prebiotic — it encourages growth of good bacteria (probiotics in the gut). This is the reason it is added to formula milk.

2) What’s this allergy about?
GOS allergy is similar to any other immediate food allergy. After it’s eaten/drunk (usually within half an hour), there are symptoms that include itchy rashes, swelling of lips, eyes or face, sneezing and a runny nose, and sometimes coughing and wheezing.

3) So is it like lactose intolerance?
They are very different — lactose intolerance only results in gut symptoms such as bloatedness, tummy pain and sometimes diarrhoea.

It is also different from dust-mite allergy, which is an inhalant allergy and usually produces respiratory symptoms such as sneezing, itchiness of nose and eyes, a running nose and sometimes asthma symptoms of coughing and wheezing.

4) Cow’s milk allergy?
GOS allergy is not cow's milk allergy.

5) How do we treat it?
If there is GOS allergy, avoidance of milk or dairy products that is fortified with GOS is needed. In Singapore, only formula milk is fortified with GOS. The additive GOS used is produced by enzymes from bacteria. Its structure is likely to be different from natural GOS present in human milk.

Dr Lee concluded, “We do not fully understand GOS allergy at the moment and we do not know if it can be ‘outgrown’. We have found adults with GOS allergy. The source of GOS [involved] is important.”

Dr Lee Bee Wah is a paediatrician with a special interest in childhood allergy at The Child and Allergy Cinic at Mount Elizabeth.

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