The benefits of regularly consuming peanut-containing foods early in life to prevent the development of peanut allergy continue even after stopping peanut consumption for one year, according to a new study led by Gideon Lack, M.D., of King’s College London. Lack announced the results at last week’s meeting of the American Academy of Allergy, Asthma and Immunology in Los Angeles. National Peanut Board provided funds for LEAP-On and its predecessor LEAP.

Building on 2015 LEAP study

Published in the latest issue of New England Journal of Medicine, the LEAP-On study was the next phase of the LEAP (Learning Early About Peanut Allergy) study, which found that the majority of infants at high-risk of developing peanut allergy (i.e., those with egg allergy, severe eczema or both) are protected from peanut allergy at age five years if they eat peanut frequently, starting within the first 11 months of life.

To maintain tolerance, do subjects have to continue to eat peanut?

LEAP-On asked whether those infants who had consumed peanut in the LEAP study would remain protected against peanut allergy if they then stopped eating peanut for 12 months. The study findings conclude that the early introduction of peanut protects against the development of peanut allergy, and such protection continues even when peanut is no longer consumed for 12 months.

The LEAP-On study was completed with 550 participants. All participants were instructed to avoid peanut for 12 months after they had completed the LEAP study, regardless of whether they had been avoiding or eating peanut in the LEAP study. At the completion of LEAP-On, participants completed an oral peanut challenge. Additional peanut allergy assessments were made by questionnaire, skin prick test (SPT), and peanut-specific immune markers IgE and IgG4 were also measured in participants’ blood.

After one year of peanut avoidance, prevalence of allergy was reduced by 74% for those who were introduced early to peanuts

The study found that at 6 years of age, there was no statistically significant increase in allergy after 12 months of avoidance, in those who had consumed peanut during the LEAP trial (3.6% at 60 months versus 4.8% at 72 months). The study also found that peanut allergy was significantly more prevalent in those who had avoided eating peanuts in LEAP, than those who consumed (18.6% vs 4.8%). There were only 3 subjects from the peanut consumption group who developed new peanut allergy during the 12 months of peanut avoidance, but there were also 3 subjects from the avoidance group who developed new peanut allergy.

The authors therefore concluded that in infants at high-risk for allergy in whom peanut was introduced in the first year of life, and continued until age 5, a 12-month period of peanut avoidance was not associated with a significant increase in peanut allergy. Overall, the study saw a 74% relative reduction in the prevalence of peanut allergy in those who consumed peanut compared to those who avoided.

Unknowns: How much or how often peanut should be consumed in early life to prevent allergy

The authors caution that the LEAP study design did not allow a determination of the minimum frequency or amount of peanut consumption required in early childhood to prevent an allergic response to peanut. Further studies are planned to establish whether the effects of early-life peanut consumption followed by ad-lib consumption of peanut over many years maintains this protection against allergy.

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