The evolution of food allergy management – Dr Adam Fox and Julia Marriott at Food Matters Live 2018
At the FreeFrom seminars, at this years’ Food Matters Live event, Dr Adam Fox and paediatric allergy dietition Julia Marriott gave a fascinating overview of how the management of food allergy, especially among children, has developed over the last 10 years. Below are some notes from their presentations.
Dr Adam Fox -
In 2006 management of food allergy was all about avoidance:
Twelve years later, thanks to some seminal research studies during that time, the approach is far more proactive.
Dual allergen exposure hypothesis
There is also a growing interest in the ‘dual allergen exposure hypothesis’.
This suggests that if the infant’s first exposure to a food allergen is through the skin – usually via broken eczematous skin – then it will be perceived by the infant’s immune system as something dangerous (an allergen). But if its first exposure is via the stomach and the gastrointestinal tract it will not be perceived as being dangerous and ‘tolerance will be induced’.
The LEAP study and the early introduction of allergenic foods
The change in management approach has come about mainly as a result of the LEAP study in 2015 which found that introducing peanuts as a weaning food to infants with severe eczema (and therefore at high risk of developing peanut allergy) dramatically reduced the likelihood of them going on to develop that peanut allergy. These results were also found in further later studies, to apply to egg allergy.
(The study was ‘inspired’ by the observation that Jewish children in Israel who were weaned on, among other foods, a peanut mush, had a very low incidence of peanut allergy whereas Jewish children in the UK – with exactly the same ethnic and societal background – who were prevented from even coming to contact with peanuts, had a very high incidence of peanut allergy.)
Following on from these findings new guidelines for weaning atopic children (those with a high risk of developing allergy) have now been developed.
(And following fast on the development of the guidelines has come the commercial exploitation. Already on the market are early weaning foods, such as Inspired Start, designed to introduce your infant to all of these allergens.)
Faecal microbiota dysbiosis (the disruption of the gut bacteria) and allergy
Increasing evidence suggests that a lack of diversity in infant gut bacteria can also be a factor in the development of childhood atopy and asthma.
It would appear that the following could reduce gut bacteria diversity, thereby increasing the risk of allergy:
On the other hand increasing gut bacteria diversity by any/all of the following would reduce the risk of allergy:
Cow’s Milk allergy
Management of cow’s milk allergy, like the management of peanut allergy, had traditionally been based on total avoidance. However, because cow’s milk is used as an ingredient in so many foods this can be very restrictive.
However, there appeared to be a difference in the behaviour of the IgE antibodies in children who outgrew their milk and egg allergies and those who did not.
It appeared, and varies studies have supported this idea, that those who had the antibodies that suggested that they would outgrow their allergies might be able to tolerate baked milk and egg while they could not tolerate these food raw.
It also appears that eating these foods baked may help to resolve the allergy quicker in those children.
Meanwhile the 2014 trials at Addenbrookes in showed that desensitisation was possible even for serious food allergy.
(Desensitisation – gradually building up tolerance to an allergen by taking tiny but gradually increasing doses of it – has been used successfully for hay fever for a number of years.)
However, although this treatment is now available in the UK via the Cambridge Allergy Clinic – it is very slow and expensive and not yet available on the NHS.
However, both in the US and in Europe, trials continue of other ways to develop peanut (or other allergen) desensitisation treatments. Aimmune Therapies have recently completed a second stage trial on a capsule containing peanut protein and DBV Technologies are also working on a patch.
Putting Allergy management into practice
As Dr Fox has just described, the understanding of allergy is changing rapidly so it is crucial that health care professionals further down the line are kept up to date with the very latest guidelines.
Speed of diagnosis and quality of treatment remains very much a postcode lottery and depends largely on who the parent sees on their first visit. Moreover, the parents are usually quite shocked by the diagnosis and take in little of what they are told. So, at their first appointment with the dietitian they want to know:
And parental reactions, concerns and issued can include:
So what does the dietitian need to take account of?
So the discussion needs to include:
So what can the dietitian offer?
2 or 3 ideas for:
It is also helpful to discuss:
Advise on adapting standard recipes: