The evolution of food allergy management – Dr Adam Fox and Julia Marriott at Food Matters Live 2018
At the FreeFrom seminars, at last year’s Food Matters Live event, Dr Adam Fox and paediatric allergy dietician 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 his presentation. By Michelle Berriedale-Johnson.
Dr Adam Fox –
President of the British Society of Allergy & Clinical Immunology; Commercial Medical Director for Guy’s & St Thomas’ Hospitals NHS Foundation Trust; Reader in Paediatric Allergy at King’s College London; founding Director of the King’s College London Allergy Academy and a trustee of Allergy UK and chair of their Health Advisory Board.
In 2006 management of food allergy was all about avoidance:
- Strictly avoid suspected allergenic foods in hope that allergy would not develop
- Make sure that the child ate a nutritious diet
- Teach the family how to manage reactions if and when they happened.
- Wait and watch in the hope that ‘tolerance’ of the allergen would develop.
Twelve years later, thanks to some seminal research studies during that time, the approach is far more proactive.
- An early introduction of the suspect food allergen (especially peanut) is now encouraged in the hope of ‘inducing tolerance’ before the allergy can develop
- Children with milk and egg allergy are being subdivided into those who may be able to tolerate those foods baked and those who cannot. The children who can tolerate baked egg and milk are being encouraged to eat them regularly.
- There is a growing awareness of the role of gut bacteria and the microbiome in the development of food allergy.
- There is a growing interest in how pre and probiotics might affect the likelihood of developing an allergy.
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:
- Being a single child – no siblings
- Caesarean delivery (so no acquisition of the mother’s bacteria as the child passes through the birth canal)
- Being fed junk baby foods
- Being treated with antibiotics
- Coming into contact with too many disinfectants and antiseptic agents
On the other hand, increasing gut bacteria diversity by any/all of the following would reduce the risk of allergy:
- Having siblings and communal childcare
- Having pets
- Having a natural birth
- Living on a farm
- Being breastfed
- Eating raw milk, fermented foods, high fibre foods and homemade foods
- Ingesting probiotics and exposure to a wide variety of organisms.
Cow’s Milk allergy
Management of cow’s milk allergy, like the management of peanut allergy, had traditionally been based on total avoidance. 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 various 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 Addenbrooke’s 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.
Julia Marriott, Community Paediatric Lead Dietitian at Essex Child & Family Wellbeing Service
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:
- Is it really an allergy?
- Why has this happened?
- Will they always have this allergy?
- Why did not pick up on it earlier?
- Is it OK to give the child artificial milk?
What can I feed them?
Parental reactions, concerns and issued can include:
- Denial – I don’t think they really have an allergy
- Fear of a reaction and how to deal with it
- Poor understanding of what an allergy is or means
- Lack of money
- Poor cooking skills/facilities
- Prejudice against specialist formulas or Free From products because they don’t like them, or someone told them they are horrible
- Advice (incorrect) from well-meaning family and friends
- Social media! (Some sites can give very confusing and/or misleading advice.)
So what does the dietitian need to take account of?
- Is this the first child with an allergy, or do they have an older sibling?
- Weight. Are they growing as expected? Do they need additional calories? Are symptoms affecting intake or absorption?
- Can they read English? Can they read labels? Do they know what they are looking for? Are they checking all foods or just obvious sources?
- Can they cook? Do they have extended family locally who can help? Do they have facilities at home for cooking? What shops/supermarkets are accessible?
- Who else is in the family home? Who else feeds the children (childminder/nursery/grandparents)?
- What can they afford?
So the discussion needs to include:
- Milk Substitutes – dairy/soya alternatives. Encourage them to use fortified substitutes whenever possible.
- Breads and wheat bread alternatives
So what can the dietitian offer?
Two or three ideas for:
- Family Meal
- Places nearby to eat out
It is also helpful to discuss:
- Cost – a free from diet maybe 30-40% more expensive than a normal diet – how are they going to afford that?
- Reading labels and learning to identify their problem food in an ingredients list.
- Suitable staple foods: fruit & veg/meat, fish & pulses/potatoes, rice and pasta – base meals round these foods
- Get some examples of family foods eaten so you can talk through which are safe, which can be adapted easily and how.
- Discuss common causes of accidental exposure – processed meat products/bread/coconut latte
- Find out where they shop, have an idea of suitable safe foods available to give examples
Advise on adapting standard recipes:
- Straight swap margarine for dairy/soya free spread. Hard margarine or shortening e.g. Stork block/Trex/Cookeen has lower water content and is better in pastry
- Biscuit/pastry recipes work with a straight swap to gluten free flour
- Cake recipes may need less flour or more liquid if converting to gluten free
- In a recipe with 1 egg, it can be substituted with 60mls fluid, fruit puree, mashed banana. (more than two eggs in recipe more difficult)
- Aqua faba (chickpea water) can be used in place of beaten egg white/meringue
- Beaten egg for coating can be replaced with batter made from milk substitute and flour/gf flour – use to stick on crumbs/cornflakes.
Milk substitutes may need additional flour/cornflour to thicken sauces.
This article was first published in Allergy Newsletter No. 125 Spring 2019