Leading Imperial researcher: Early exposure could reduce later risk of allergy
21 September 2016 • Author(s): Roy Manuell, Digital Content Producer
Following a study conducted by Imperial College London that sought to discover whether feeding babies certain allergens might lead to the prevention of suffering from an allergy to the same substance in later life, New Food decided to investigate further by speaking to lead researcher, Robert Boyle…
1. For the purpose of our readers, could you explain how you arrived at the conclusion of the research that introducing allergens to babies might reduce the risk of the later development of allergies?
Food allergy is a common problem which may be getting more common. We have known for over 100 years that feeding egg to animals such as guinea pigs can prevent egg allergy. However randomised trials of allergenic food introduction for preventing food allergy in human infants have not been done until the past 5-10 years, and have so far yielded mixed results.
One trial for peanut allergy was positive, with less peanut allergy in infants who were fed the food from early in life compared with infants who avoided it for 5 years. Other trials have yielded null findings, but may have been too small to yield a conclusive result. We used a technique called meta-analysis to combine the results of all previous trials of timing of allergenic food introduction and risk of food allergy.
We also evaluated other allergic and autoimmune diseases. Our analysis yielded conclusive results for both egg and peanut – that early introduction of these foods into an infant’s diet might reduce their risk of egg and peanut allergy by around 40-70%. We were surprised to see null findings in our meta-analysis of timing of gluten or wheat introduction and risk of coeliac disease (gluten intolerance) which is a different type of allergy to egg and peanut allergy.
This suggests that early introduction of allergenic foods does not reduce risk of all types of food allergy.
2. What limitations should we be aware of with respect to the conclusion?
The results are based on a small number of studies (5 for egg; 2 for peanut). Although it is unlikely that future studies will show an early egg and peanut consumption doesn’t work for the prevention of egg and peanut allergy, they may show our estimates of precisely how effective this is (i.e 40% and 70% reduction in risk) to be inaccurate. A second limitation is that giving egg and peanut to young infants with troublesome eczema or other signs of food allergy may not be safe, since an allergic reaction can be triggered. Third, it is important to add that whole peanuts are not recommended for young children due to the choking hazard.
3. Will you be continuing research on the subject?
The Food Standards Agency, who funded this project, are now undertaking a risk benefit analysis together with other UK government departments, to evaluate how these findings should impact on infant feeding guidelines.
4. What do you believe the government and central authorities should do in light of the findings?
My personal view is that parents should be advised to feed allergenic foods such as egg and nuts to their infants, if these foods are eaten in the family home. There are two caveats to this: first that as mentioned above whole nuts should not be given to infants, so nuts need to be in the form of smooth nut butters; second that infants with troublesome eczema or other signs of food allergy should not be given allergenic foods without consulting with a doctor first, who may advise an allergy test or assessment by an allergy specialist.
5. On a more general note, what challenges does society as a whole face with respect to allergens compared to say 20 years ago?
Because food allergy is now recognised as a common condition, we have a societal challenge in controlling and monitoring allergenic foods in food supplies. There is still further work to do in food production, labelling, and risk communication. We need simpler approaches to preventing allergic conditions, that are easy for parents to follow; and we need to understand more about severity of reaction in people with food allergy. Allergic diseases are the commonest long-term health conditions in many parts of the world, and we need to know more about them in order to prevent and treat them effectively.
About Robert Boyle…
Clinical Senior Lecturer in Paediatric Allergy, St Mary’s Campus.
Dr Boyle was appointed to Imperial College London as NIHR Clinical Lecturer in 2007, Clinical Senior Lecturer in 2009, and Director of the Paediatric Research Unit from 2013…
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