King's College. UK: New evidence shows that the majority of infants at high-risk of
developing peanut allergy are protected from peanut allergy at age 5
years if they eat peanut frequently, starting within the first 11 months
of life.
For many years Public Health Guidelines, Paediatricians and
Allergists have recommended avoiding foods in infant’s diet that cause
allergies such as peanut. However, the LEAP (Learning Early About Peanut
Allergy) study led by Professor Gideon Lack, King’s College London, and
published in the New England Journal of Medicine, is the first
study to show that consumption is an effective strategy to prevent food
allergy, contradicting previous recommendations.
The incidence of food allergy has risen in recent decades, and
peanut allergy now affects up to 1 in 50 school age children in the UK;
the occurrence of peanut allergy has more than doubled in the last 10
years in the UK and North America. It affects between 1-3% of children
in Western Europe, the USA, and Australia and in recent years has become
an important cause of food allergies in African and Asian countries.
Peanut allergy develops early in life, is rarely out-grown and there is
currently no cure. It imposes a considerable burden, impacting
negatively on quality of life for patients and their families.
The LEAP study, a randomized controlled trial, enrolled 640
children aged 4-11 months from Evelina London Children’s Hospital, who
were considered at high-risk of developing peanut allergy due to
pre-existing severe eczema and/or egg allergy. To determine whether
peanut consumption or avoidance is the most effective strategy to
prevent peanut allergy, half of the children were asked to eat
peanut-containing foods three or more times each week, and the other
half to avoid eating peanut until 5 years of age. Adherence to peanut
consumption or avoidance advice was assessed using a food frequency
questionnaire at regular intervals during the study and by measuring
peanut levels in the child’s home environment.
Remarkably, less than 1% of children who consumed peanut as per
study protocol and completed the study developed peanut allergy by 5
years of age, while 17.3% in the avoidance group developed peanut
allergy. Even when considering all children enrolled - including those
participants who were unable to tolerate peanut consumption (13 of the
319 children who were randomised to peanut consumption had some allergic
responses to peanut during the study) - a powerful protective effect
against the development of peanut allergy remains: the overall
prevalence of allergy in all children asked to consume peanut was 3.2%
versus 17.2% in the avoidance group. This represents a greater than 80%
reduction in the prevalence of peanut allergy. Nearly all participants
enrolled on the LEAP study completed the final assessment at age 5 years
(98%).
Importantly, the early introduction of peanut-containing foods was
found to be safe and well tolerated; infants were not fed whole peanuts
which carry a risk of choking in young children.
The study was therefore able to conclude that early, sustained
consumption of peanut is safe and associated with a substantial and
significant decrease in the development of peanut allergy in high-risk
infants by the age of five. Deliberate avoidance of peanut in the first
year of life is consequently brought into question as a strategy to
prevent allergy.
Professor Gideon Lack, Head of Department of Paediatric Allergy,
King’s College London and Head of the Children’s Allergy Service at
Guy’s and St Thomas’ NHS Foundation Trust, who led the study, presented
the findings at the American Academy of Allergy, Asthma and Immunology
meeting (AAAAI): “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.”
Professor Lack further noted that: “The study also excluded
infants showing early strong signs of having already developed peanut
allergy; the safety and effectiveness of early peanut consumption in
this group remains unknown and requires further study. Parents of
infants and young children with eczema and/or egg allergy should consult
with an Allergist, Paediatrician, or their General Practitioner prior
to feeding them peanut products.”
Dr George Du Toit, consultant in Paediatric Allergy at Guy’s and
St Thomas’ NHS Foundation Trust and honorary senior lecturer, King’s
College London, co-investigator of the study, said: “The next stage of
our work, the LEAP-On study, will continue to monitor those children who
consumed peanut to see if they remain protected against allergy even if
they stop consuming peanut for 12 months. The LEAP-On study will help
establish if the protection provided against the development of peanut
allergy is sustained and not dependent on ongoing peanut ingestion.”