Families with children who have peanut allergy have to be constantly vigilant about their food.
The new study - the first trial to show that consumption of a food is an effective strategy to prevent allergy to it - appears to contradict the idea that children should avoid eating peanuts so they do not develop peanut allergy.
The rate of food allergy has climbed steadily in recent decades. Peanut allergy affects 1-3% of children in the US, Western Europe and Australia, and evidence has emerged that it is also beginning to affect children in Asia and Africa.
Allergy to peanuts develops early in life. Once it develops, it is rarely outgrown and there is no cure. Those most at risk are children with a family history of peanut allergy, who have eczema or are allergic to eggs.
A severe reaction to peanuts is a potentially fatal condition called anaphylaxic shock. The continual threat of this places a heavy burden on the sufferers and their families, who have to be constantly vigilant about the food their children are eating at home and elsewhere.
Israeli children eat peanuts early in life and have lower rates of allergy
Now a clinical trial led by King's College London in the UK and supported by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health in the US, found that introducing peanut products into the diets of infants at high risk of developing peanut allergy was safe and resulted in an over 80% percent reduction in the subsequent development of the allergy.
A report on the findings was presented at the annual meeting of the American Academy of Allergy, Asthma and Immunology in Houston, TX, on Monday and is published in the New England Journal of Medicine.
Trial leader Gideon Lack, a professor and head of the Department of Paediatric Allergy at King's College London, and colleagues decided to carry out the study - called Learning Early About Peanut Allergy (LEAP) - after observing that Jewish children brought up in Israel have lower rates of peanut allergy than Jewish children of similar ancestry brought up in the UK.
Unlike children in the UK, children in Israel are frequently fed peanut-containing products early in life.
The purpose of the LEAP trial was to test the idea that the very low rates of peanut allergy in Israeli children may be due to the fact they start eating peanut products in high quantities early in life.
LEAP is a randomized controlled trial that enrolled 640 babies aged 4-11 months and their families through a London hospital. The children were assessed as having a high risk of developing peanut allergy because they either had eczema or egg allergy.
Trial results show over 80% reduction in the rate of peanut allergy
For the trial, the babies were randomly assigned to one of two groups. In one group, the families of the babies were asked to give their infants peanut-containing products three times a week or more. The other group was asked to avoid giving their babies peanut-containing foods until they were 5 years old.
The researchers checked how well the families followed these requests via questionnaires and also by testing peanut levels in their homes.
Ninety-eight percent of the children completed the study and were assessed at age 5.
The results show that less than 1% of the children who were given peanut products and who completed the study in line with the protocol, developed peanut allergy by the age of 5, compared with 17.3% of those who avoided peanut products in that time.
Even if you count all the children enrolled on the study - including the 13 of the 319 randomized to eat peanuts but who could not tolerate it from the start - the analysis shows there appears to be a powerful protective effect from introducing peanut consumption early in life.
The overall rate of allergy in the children who were given peanut products was 3.2% compared with 17.2% in the avoidance group. This translates to an over 80% reduction in the rate of peanut allergy.
The researchers note that in the peanut group, early introduction of the food was well tolerated and safe.
Importantly, the children were not given whole peanuts - because of the risk of choking - they were given a baked snack containing 50% peanuts and fortified with vitamins and iron that is popular in Israel.
The authors conclude that:
"The early introduction of peanuts significantly decreased the frequency of the development of peanut allergy among children at high risk for this allergy and modulated immune responses to peanuts."
Results question the idea that food should be avoided early in life to prevent allergy
For many years, public health guidelines and the advice of pediatricians and allergy experts was we should avoid giving babies products like peanuts that might trigger allergies.
Prof. Lack says:
"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 also notes that the study did not include babies showing early strong signs of peanut allergy so they cannot say whether early peanut consumption would be a safe or effective allergy-prevention strategy in this group. He advises:
"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."
The researchers are continuing with the trial. One of the questions the further investigation is exploring is whether the protection against peanut allergy is sustained or whether it depends on continuing to consume peanuts, as co-investigator and first author of the study, Dr. George Du Toit explains:
"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."
Dr. Du Toit is consultant in Paediatric Allergy at Guy's and St. Thomas' NHS Foundation Trust and honorary senior lecturer at King's College London.
Meanwhile, Medical News Today recently learned of a study that suggests dishwashers may make children more prone to allergies. In the journal Pediatrics, researchers report the preliminary findings of an observational study where they found families who wash their dishes by hand, rather than in a dishwasher, have children with fewer allergies.