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expert reaction to two studies investigating peanut allergy and peanut consumption in early years

Publishing in the New England Journal of Medicine two groups of researchers have investigated the effects of consumption of certain foods as a baby on allergy later in life.


Prof. Barry Kay, Emeritus Professor of Allergy and Clinical Immunology, Imperial College London, said:

“A Department of Health publication, ‘Birth to Five’, published in 2007 recommended that peanut or peanut products “should not be given to babies from ‘atopic’ or ‘allergic’ families until they are at least three years old.” Despite this advice the prevalence of peanut allergy, including deaths from anaphylaxis, continued to increase.

“In their first LEAP study, published in 2015, Professor Lack and colleagues found just the reverse i.e. that controlled early introduction of peanuts to high-risk infants, within the first 11 months, was associated with protection against food allergy. The team now follows up* this seminal work by demonstrating that after five years of treatment, tolerance was maintained after discontinuation of peanuts for one year.

“In an accompanying articleǂ they demonstrate that early introduction of allergic foods to breastfeeding infants at risk is also associated with a low prevalence of food allergy. In this paper, there was a statistically significant difference between those who kept to the protocol and those that didn’t (lower rate of food allergy in those that kept to the protocol) but not in the group as a whole (i.e. the intention to treat group which include ‘protocol violations’).

“These are landmark studies which have occupied a committed team of investigators over a 10 year period. The results point the way to completely fresh thinking on the mechanisms of tolerance to allergenic foods in “at risk” infants and have the potential to provide future advice for prevention based on stringent experimentation. They rank amongst the most important studies ever published in the field of food allergy and are a credit to the dedication and ingenuity of British clinical scientists.

“A note of caution – these studies were performed by trained allergists under controlled conditions. There are a few questions still to be answered before new, general, advice can be given. For instance, what are the correct amounts of foods needed to induce tolerance, and what is the age where it is too late to induce tolerance? There are also issues around the preparation of foods to make them easier for parents to administer. So, don’t try this at home yet.”


Michael Walker, of Michael Walker Consulting Ltd, and Consultant Referee Analyst to the Government Chemist, said:

“The two studies ‘LEAP-On’* and ‘EAT’ǂ published today in the New England Journal of Medicine are important and reassuring additions to our knowledge about possible prevention of food allergy. Both were conducted to high standards by well-regarded teams. In particular the participation and adherence rates were excellent.

“LEAP-On studied infants at high-risk of developing peanut allergy. Infants at high-risk of developing peanut allergy were defined for the study as those with suspected egg allergy based on skin prick testing, and /or with severe eczema based on a clinical evaluation that combined the extent, severity and subjective symptoms of the eczema, and the treatment required.

“The earlier LEAP (Learning Early About Peanut Allergy) study from 2015 found, somewhat counter-intuitively, that the majority of such high risk infants can be protected from peanut allergy at age 5 years if they eat peanut frequently, starting within the first 11 months of life. The LEAP-On findings are that early peanut introduction protection is sustained even when peanut is no longer consumed for 12 months.

“EAT (Enquiring about Tolerance) in contrast looked at breast fed infants from the general population and the early introduction of six major allergenic foods, peanut, cooked egg, cows’ milk, sesame, whitefish and wheat. There were very encouraging findings that peanut and cooked egg allergy in particular and food allergy generally was lower with early introduction. Moreover, although not easy, such introduction was safe.

“Taken together these are reassuring findings that pave the way to stem the epidemic of peanut allergy. These studies were carried out under the close guidance of allergy doctors. Parents shouldn’t attempt to replicate what the studies did by themselves but should follow general guidance, for example that encourages mums to breast feed, and common sense attitudes to weaning, introducing a wide variety of foods as appropriate. Parents and carers, especially with infants at high risk, should bring any concerns to their GP for advice.”


* ‘Effect of avoidance on peanut allergy after early peanut consumption’ by George Du Toit et al. published in the NEJM on Friday 4 March 2016.

ǂ ‘Randomized trial of introduction of allergic foods in breast-fed infants’ by Michael R Perkin et al. published in the NEJM on Friday 4 March 2016.


Declared interests

Prof. Barry Kay: “I have no conflicts.”

Michael Walker: The views expressed here are those personally of Michael Walker and do not represent the official views of LGC.  Interests:

Paid employment or self-employment – I manage analytical allergen detection research in the publically funded Government Chemist Programme in LGC, I was facilitator for the Safefood publically funded Food Allergy & Food Intolerance Network 2011 – 2015 under contract to LGC,

Grant funding – see above

Voluntary appointments – Chair FSA in NI Strategic Food Surveillance Committee

Memberships – Michael Walker Consulting Ltd is a corporate member of Anaphylaxis Campaign, Michael Walker is a member of the European Academy of Allergy & Clinical Immunology

Decision-making positions – none directly relevant

Other financial interest – none

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