Prevention of peanut allergy in children: understanding the LEAP Study
Q&A for the peanut industry
What is LEAP?
“Learning Early about Peanut Allergy” (LEAP) is a randomised and controlled five-year clinical
intervention trial based in London, UK, which reported initial results in 2015. The results were
published in the New England Journal of Medicine on 26 February 2015 as “Randomized Trial
of Peanut Consumption in Infants at Risk for Peanut Allergy” with an accompanying editorial
“Preventing Peanut Allergy through Early Consumption — Ready for Prime Time?” In the
same issue there is a short video explaining the study and its results in graphic form. This
material is in the public domain and can be freely downloaded at
www.nejm.org/doi/full/10.1056/NEJMoa1414850
What is LEAP’s key finding?
The study’s bottom line is the cause and effect demonstration that consumption of a snack
containing peanut protein (Bamba) or peanut butter by infants who are at high‐risk for
developing peanut allergy prevents the subsequent development of allergy in a very high
percentage. Put another way, early dietary exposure to peanut allergen was shown to promote
the development of tolerance to peanuts by the child’s developing immune system and is
highly effective in preventing allergic reactions to peanuts in later life for this high risk group.
The intervention used in LEAP was safe, well-tolerated and, most important of all, highly
effective. At age 5, peanut consumption was associated with an 86% reduction in peanut
allergy among children testing negative for peanut sensitisation when the study began and with
a 70% reduction in peanut allergy among those who had had positive skin-prick test results at
study entry.
Lead investigator Prof Gideon lack, King’s College London, said: “For decades allergists have
been recommending that young infants avoid consuming allergenic foods such as peanut to
prevent food allergies. Our findings suggest that this advice was incorrect and may have
contributed to the rise in the peanut and other food allergies. … This is an important clinical
development and contravenes previous guidelines. Whilst these were withdrawn in 2008 in the
UK and US, our study suggests that new guidelines may be needed to reduce the rate of
peanut allergy in our children."
Has the US peanut industry supported peanut allergy research including LEAP?
Yes. National Peanut Board President and CEO Bob Parker said, “Research like LEAP, which
demonstrates there are ways to reduce the risk of a child developing a peanut allergy, brings
hope to families everywhere. … That is why U.S. peanut farmers – through the National
Peanut Board – have contributed more than $12 million toward independent food allergy
research, education and outreach worldwide over the past 15 years, and plan to continue to be
part of the solution.”
Some online comments have expressed concern that the peanut industry was involved in the
LEAP funding. This support was fully disclosed in the study itself and the industry’s role has
been put into perspective by a statement from FARE (Food Allergy Research and Education)
making it clear that the industry had no influence over the outcome: “ ….the vast majority of
the study’s funding came from the National Institutes of Health and FARE. The National
Peanut Board, a minority funder, was contractually prohibited from influencing any aspect of
the study design or interpretation of the results.”
http://blog.foodallergy.org/2015/03/11/correcting-misconceptions-about-the-leap-study/
A complete list of funders can be found at end of the LEAP study itself published in NEJM.
Does LEAP mean peanut allergy has been cured?
No. The study was about prevention of peanut allergy – not curing existing allergy – in a
selected group of infants under 12 months of age who were at high risk of developing peanut
allergy later in life because they had risk factors such as eczema and egg allergy. The study
children were included because of these risk factors. Children without these risk factors or in
whom it was thought peanut allergy had probably already developed because of the degree of
their sensitisation to peanut, were excluded from the study.
LEAP is not a treatment or a cure for existing peanut allergy in children. The findings are not
applicable to adults.
Dr Andrew Clark, paediatric allergy specialist at Addenbrooke’s Hospital, Cambridge said:
“[LEAP] challenges the way we think about first introduction of foods. In the past there was a
lack of studies telling us what the best way was to avoid children having allergies. It was
thought best you shouldn't give children allergenic foods. That's the whole dogma this study
challenges. In a positive way I think it could mean we can improve the way we feed infants to
reduce the number of food allergies in the future."
Did consuming peanut protein work for all of the children in the LEAP study?
No, but it did create tolerance (known as “unresponsiveness”) to peanut protein in a high
percentage of at risk infants. Of those avoiding peanut during the trial, about 17% had become
peanut allergic by age five. However, of the group eating peanut every week, only 3% were
allergic to peanut by age five. It is important to remember that these were all high risk infants,
not the general population.
LEAP was a very well designed and safe intervention. Ninety-eight percent of the children
remained in the study until the end when they were five years old. Only one child needed
epinephrine (adrenalin) and any reactions which did occur were mild to moderate.
It has to be stressed that these are prevention outcomes. LEAP was not a study looking at
treatment of children with peanut allergy and its results have nothing to say about a “cure” for
peanut allergy or the treatment of anyone who has had prior allergic reactions to peanuts.
Could the approach used in the LEAP study be used to treat peanut allergy?
As LEAP is refined for clinical practice, it may be possible to identify and build up tolerance to
peanut in high risk young children by introducing peanut products such as peanut butter into
their diet from an early stage. This is primary prevention.
For those already with established peanut allergy, there are experimental treatments which
may become available in the future. These include oral immunotherapy (OIT) and skin patch
technology (epicutaneous immunotherapy), both of which have been shown to create
tolerance in some individuals by introducing increasing doses of peanut allergen.
Do the LEAP results have implications for preventing allergies to other foods?
While LEAP was exclusively about peanut allergy, the approach it used is reflected in a study
of early introduction of other foods called EAT – “Enquiring About Tolerance”. This is testing
the hypothesis that the introduction of six allergenic foods (fish, egg, dairy products, wheat,
sesame and peanut) into the diet of infants from 3 months of age, alongside continued
breastfeeding, results in a reduced prevalence of food allergies by 3 years of age. The EAT
study is expected to report in September 2015. www.eatstudy.co.uk/eat-study-info
Is the tolerance to peanut allergen shown in the LEAP results permanent, or will it need
“topping up” in these children from time to time?
This is not known at the moment, but a 12 month follow-on study, called “LEAP-On” should
have the answer in about February 2016. In LEAP-On, the participants from LEAP who ate
peanut and did not become allergic will stop eating peanut completely and undergo a peanut
food challenge 12 months later. This will show if the “unresponsiveness” lasts or not.
The study talks about “consuming peanut”. Is this just another way of saying “children
eating peanuts” or “feeding children peanuts”?
No and the difference is important. Some media reports talked about “babies eating peanuts”
or “feeding peanuts to babies” both of which are misleading and potentially dangerous. The
LEAP trial used peanut protein contained in peanut products, such as the puffed snack food
Bamba (see below) or smooth peanut butter, which were eaten in a supervised clinical setting
and all the children were skin prick tested for peanut sensitivity before being enrolled in the
study. That is what “consuming peanut” means in the context of the LEAP study.
LEAP did not use whole peanuts because of the danger of very young children choking on
them. Nor did it imply that consumption could be done outside of a supervised clinical setting.
Some media reports are dangerously misleading by implying that LEAP gives permission for
parents to start feeding whole peanuts to very young children or to introduce peanut products
to high risk children who have not been screened to determine their degree of sensitivity.
Dr James Baker, CEO of Food Allergy Research & Education (FARE) said, “Parents should
not simply hear a "consume peanut" message. We hope that parents understand this isn't
something you do without consulting a physician and making absolutely sure the child is not
allergic first,"
Some media reports about LEAP use the expression “exposing children early to
peanuts”. What does that mean and is it an accurate description of what happened in
LEAP?
The phrase is ambiguous and should not be used as it does not describe what happened in
the LEAP trial. It is known that exposure via direct skin contact to protein containing peanut
particles or residues can result in sensitisation to peanut in very young children if the skin
barrier is compromised, eg if a child has eczema. LEAP was about the consumption of peanut
protein by eating it so that it was absorbed through the gut not through the skin. “Exposure”,
therefore, is not a good word to use in connection with LEAP, but if it is used it must always be
made clear that “dietary exposure”, ie consuming by eating, is meant.
What is the snack Bamba and why was it used in the LEAP trial?
“Bamba” is the brand name of a popular snack product in Israel, eaten by virtually everyone
from an early age. It is a puffed maize snack product containing peanut butter
http://en.wikipedia.org/wiki/Bamba_%28snack%29 The LEAP trial used 25g (1oz) packs of
Bamba. 17g or 2/3 of the Bamba pack provided 2g peanut protein, and the children consumed
this 3 times per week.
Bamba was used because an observational study in 2008
(www.ncbi.nlm.nih.gov/pubmed/19000582) found that Israeli children have lower rates of
peanut allergy compared to Jewish children in the UK of similar ancestry. The Israeli children
began consuming peanut-containing foods, particularly Bamba, very early in life. LEAP
therefore investigated the hypothesis that the very low rates of peanut allergy in Israeli children
were a result of high levels of peanut consumption beginning in infancy. The Israeli children
consumed about 6-8g of peanut protein per week, so that was used as the upper limit in the
LEAP study. It isn’t known what would have happened if more or less than that amount had
been consumed.
For children in the LEAP trial who did not like Bamba, equivalent amounts of smooth peanut
butter were used instead to achieve the same effect.
Could putting peanut flour or smooth peanut butter into weaning foods for babies be a
way to achieve this result achieved by LEAP?
This has been suggested as an alternative to consuming Bamba or peanut butter, but it will
depend on how the guidelines about childhood allergy and about weaning and breastfeeding
are revised in the light of the LEAP findings and also the EAT study findings. Getting the
“dose” and the feeding frequency right are important. But it is possible that new products along
these lines could be developed once the revised guidelines are available.
LEAP studied high-risk children living in Britain, so are the findings applicable to
children in other countries?
LEAP included 640 high risk infants under 12 months old. Having an egg allergy or eczema
typically means a 15-20% chance of developing peanut allergy later. This number was chosen
to give statistical robustness to the study. If the group had been drawn from the general
population, the numbers needed for the study would have been several thousand and thus
unmanageable over five years.
All infants were screened using a peanut protein skin prick test to identify those already
showing signs of an allergic reaction. Those with large wheals (areas of raised or reddened
skin >4mm diameter) were excluded from the study because they probably already had a
peanut allergy. Those with slight wheals (< 4mm) were included in LEAP, but analysed
separately to those showing no skin reaction.
The LEAP study children were all living in the United Kingdom and predominantly white with
eczema and/or egg allergy. Geography and ethnicity must be considered before extrapolating
the results to other populations, for example older children or African-American or Hispanic
infants in the US or infants with multiple food allergies. However, the investigators have stated
that subgroup analyses of the data of Black and Asian children in LEAP suggests that the
intervention works regardless of ethnicity.
Are clinical skills at the right level to identify children at high risk of developing peanut
allergy so parents can be advised what steps to take?
Skill levels and access to clinicians with allergy expertise are real concerns for the LEAP team.
Investigator Dr George du Toit, King’s College London and Guy’s and Thomas’ NHS
Foundation Trust said, “We believe there's an urgent need for clinicians to be skilled in
identifying the at-risk population. This means a basic knowledge about atopic eczema, egg
allergy, and milk allergy, which are all risk factors for peanut allergy, and then of course skinprick testing, which in the LEAP study we found to be invaluable for dissecting risk categories.
Worldwide, not all patients — in fact a real minority of allergic patients — have access to even
those basic diagnostic skills."
Does the LEAP finding about preventing peanut allergy mean that educational
approaches to food allergy management in schools and other settings will not be as
important in future?
No and in many ways these initiatives will become even more important. Encouraging as LEAP
is for the future, no one should be under any illusion that LEAP’s findings mean that peanut
allergy is no longer a serious issue for many individuals who are already allergic. The need for
allergy-safe and evidence-based management practices – particularly in schools and other
settings where children are present - and the provision of accurate information to food allergic
consumers has not gone away because of LEAP. In many ways the need for these things will
become more urgent and the American peanut industry will continue to support such initiatives.
We want the 98% of the population who are not peanut allergic to be able to enjoy peanut
products without food bans and restrictions while the 2% or thereabouts of the population who
may have an allergy to peanuts can be safe and well-informed.
What are some reliable online sources of information about LEAP and its implications?
There is no substitute for reading the published study and the accompanying editorial in NEJM.
In addition, LEAP team members and other leading paediatric allergy specialists and patientled bodies have discussed the findings widely. Below are links to some of online sources
which are reliable and which also correct some of the misunderstandings which may develop
around the study and its implications.
Anaphylaxis Campaign www.anaphylaxis.org.uk/living-with-anaphylaxis/news/new-studyfinds-peanut-consumption-can-protect-infants-at-risk-of-developing-peanut-allergy
FARE (Food Allergy Research and Education) http://blog.foodallergy.org/2015/03/09/follow-upon-the-leap-study-qa-with-fare-ceo-james-r-baker-jr-md/
Scientific American www.scientificamerican.com/article/how-can-peanut-allergies-beprevented/?WT.mc_id=SA_Twitter
Huffington Post http://live.huffingtonpost.com/r/segment/new-study-claims-eating-peanuts-asinfant-prevents-peanut-allergy/54e7b38d78c90a8ed1000a51
NHS Choices www.nhs.uk/news/2015/02February/Pages/peanut-butter-for-non-allergicbabies-may-help-reduce-later-allergies.aspx
National Institutes of Health www.nih.gov/news/health/feb2015/niaid-23.htm
Medscape
www.medscape.com/viewarticle/840336?nlid=77043_2843&src=wnl_edit_dail&uac=11056SK
AsthmaAllergiesChildren.com http://asthmaallergieschildren.com/2015/02/25/breaking-downthe-landmark-leap-study-what-does-it-mean/
Kids with Food Allergies http://community.kidswithfoodallergies.org/blog/new-peanut-allergystudy-does-not-say-parents-are-to-blame-1
Massachusetts General Hospital for Children
https://foodallergy.partners.org/public/LEAP_response.pdf
Allergic Living http://allergicliving.com/2015/03/19/what-leap-means-to-your-family/
Compiled March 2015 by
Dr Andrew Craig
Health Consultant
American Peanut Council
Lansdowne Building (Room 222)
2 Lansdowne Road
Croydon CR9 2ER
Tel: + 44 (0) 208 263 6254
[email protected]