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 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 Lack said: "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."
He 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, of 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."
The paper, Randomized
Trial of Peanut Consumption in Infants at Risk for Peanut
Allergy, is published in the New England Journal of
Medicine.