Contemporary Weaning - An Allergist's Perspective
A common question asked of the Paediatrician is when to wean and onto which foods.
Weaning is inevitable as exclusive breastfeeding will be inadequate at sustaining growth from around 6 months of age onwards. The World Health Organisation (WHO) target remains for exclusive breastfeeding until 6 months but sadly this goal is not achieved by the majority of infants. Weaning occurs earlier than 6 months for more than 90% of infants in the UK due to infant hunger or maternal and societal factors, this will either be as a top-up or alternative infant milk formula or solid food. In most cultures around the world, weaning is typically onto root vegetables, fruits, and/or cereal grains but there is no hard science behind the optimal first foods other than these foods would need to be in a physical form that is easy and safe to swallow. Once swallowing is safely accomplished, and the infant appears hungry, I encourage mothers to trust their maternal instincts and to commence weaning. This should not be before 4 months of age but is considered safe from 4 months of age in hungrier babies; ideally, weaning would commence with ongoing breastfeeding as this will facilitate optimal nutrition and a healthy biome. Frustratingly, breastfeeding has a limited effect on the prevention of food allergies. There are of course a plethora of other good reasons why breastfeeding is healthy for both mother and infant and there is some weak evidence that breastfeeding may impact asthma and eczema outcomes.
In allergic families, or infants with eczema, the risk of developing food allergies is increased especially if the eczema is of early-onset, generalised and severe.
The window of opportunity for prevention as shown in our LEAP and EAT studies starts closing from 4 months of age. We, therefore, encourage that young infants with eczema are assessed for common major allergies such as peanut, egg, milk, cashew, wheat, fish, soy, and sesame in order that this can facilitate early expansive weaning which at the very least will be healthy, satiating and nutritious, but for some allergens, this may well be protective against developing an allergy. For example, our LEAP study showed an 81% reduction in infants with eczema in those who ate peanut between 4-11 months of age compared to those who did not.
So for the above reasons we encourage all parents of at-risk infants to consider applying allergy prevention strategies, particularly in the UK where rates are high if their infant has eczema. In the absence of eczema or any concern around GI symptoms or allergies in the family, then there is less urgency for early allergen weaning, but the intervention is, in any case, healthy and safe and so may also be applied.
The British Society for Allergy & Clinical Immunology (BSACI) early feeding recommendations have advice on peanut and egg. The Australasian (ASCIA) and American recommendations encourage early allergen exposure in the diet (NIAID). With regards to peanut, there are helpful tips for the introduction of peanut if you have the green light on the babysfirst.org website.
In summary, commence weaning on to solids when your baby displays hunger mannerisms, but not before 4 months of age. They should have good head control and have lost their ‘tongue thrust’ when challenged with foods in order to safely swallow solids. Hunger mannerisms would include more frequent waking, increased ‘hunger cries’, following foods attentively… If there are no risk factors, weaning may include all common food allergens as early in the weaning regimen as possible and without testing, indeed this is how most children are weaned in the world. For those infants with risk factors, particularly early-onset eczema, screening is wise prior to introducing the more common food allergens e.g. egg, milk, and peanut.
George Du Toit
Professor of Paediatric Allergy