High-Risk Infants Fed Peanuts Developed Allergy At Lower Rate Than Other Babies - Study May Pave Way for New Prevention Strategies

Feeding peanut butter to infants at risk for developing peanut allergies prevented those same babies from developing the allergies by the age of five – reducing their risk by a stunning rate of about 70% to 80%, researchers reported today in The New England Journal of Medicine.

In an editorial accompanying the study, Dr. Hugh A. Sampson of the Jaffe Food Allergy Institute at the Icahn School of Medicine at Mount Sinai, and Dr. Rebecca S. Gruchella at the University of South Texas Southwestern Medical Center in Dallas, called the report a “landmark study” that may be a game changer for how we feed infants at risk for peanut allergy.

Professor Gideon Lack reported on the study team’s findings Monday afternoon in Houston at the annual American Academy of Asthma, Allergy and Immunology meeting.

The study, called Learning Early About Peanut Allergy (LEAP), randomized more than 600 babies into two groups – those who would eat peanuts, and those who would avoid. At the time that they entered the study, they were between 4 months and 11 months old, and all underwent a skin-prick test to peanut to determine how sensitive they were. They also had an in-office feeding challenge to peanuts.

The babies were deemed “high risk” because they had severe eczema, egg allergy, or both.

“This is an exciting and monumental study that may forever change the way we view the role of dietary intervention in the protection against the development of food allergy,” said Dr. David Stukus, an assistant professor of pediatrics in the Allergy/Immunology Section of Nationwide Children’s Hospital in Columbus, Ohio, and chair of the Kids With Food Allergies Medical Advisory Team.

The study, which took a few years to complete, was called an “open-label” study, meaning the parents of the children knew whether they were in the group eating a peanut snack or not. The peanut snack chosen for the study is called Bamba, a peanut snack popular in Israel.

The roots of this study lay in an earlier observation researchers made previously. Then, they saw that Jewish babies in the UK, who avoided eating peanut, had much higher rates of allergy than Jewish babies in Israel, who routinely snacked on a peanut snack called Bamba. The study released Monday was specifically designed to test that theory.

This study found that:

Among the 530 infants who initially had negative results on the skin test, by the age of five, if they had strictly avoided peanuts, 13.7% of them had developed a peanut allergy.

But only 1.9% of the children who had been actively eating peanuts – the equivalent of about 8 peanuts three times a week - had become allergic.

Even in the group of 98 infants who had positive skin results as infants (meaning they were already sensitized to the peanut allergen), the results were striking. In the group of babies who avoided peanuts, 35.3% of them went on to develop a peanut allergy by the age of five. But only 10.6% of the babies eating peanuts had developed an allergy.

There was no significant difference in the rate of serious reactions between the two groups. Some babies did have to drop out of the study, but only one needed epinephrine. Most reactions were mild to moderate.

Dr. Stukus warned that parents and well-meaning friends and relatives need to proceed with extreme caution before feeding infants peanut butter.

“First, every child in this study underwent skin prick testing and physician -supervised oral challenge towards peanut before eating it at home for the first time. About 10% of possible study participants were deemed too risky to enroll due to the large size (greater than 4 millimeter) of their skin test,” he noted.

“In other words, formal evaluation and consultation by a board-certified allergist will be paramount in making sure this is the proper and safe choice to make before giving peanut to high-risk infants.”

In their editorial, Dr. Sampson and Dr. Gruchalla said that other studies are now “urgently needed” to answer questions raised by this important study, such as: Should feeding guidelines for infants be changed? If regular peanut eating is discontinued, will babies keep their tolerance? How much do they have to eat to maintain tolerance? Can the findings from this study be applied to other foods, like milk, eggs and tree nuts?

Dr. Stukus noted that the study was not 100% successful for all children who ate peanut regularly from infancy. “Roughly 2% of children with negative skin tests and 11% of children with mild skin tests developed peanut allergy. More research is needed to better determine why some children still developed peanut allergy and also whether this can be applied to other foods as well.”

Another allergist sounded a note of caution as well.

"While the results of this study were exceptionally favorable, in particular in the skin test positive group, overall there are still many unknowns regarding early introduction,” said Dr. Matthew Greenhawt, MBA, MSc and Research Director of the University of Michigan Food Allergy Center as well as Assistant Professor in the Division of Allergy and Immunology at the U-M.

“While this was a randomized controlled trial, it still involved relatively small numbers and requires further replication, in particular in US populations,” said Dr. Greenhawt, who like, Dr. Stukus, is also a member of the KFA Medical Advisory Team. “Therefore, it would seem wise to have restraint in making any sweeping recommendations to early feeding practices or early screening for peanut sensitization, as is suggested in the accompanying editorial."

Dr. Cary Sennett, President and Chief Executive Officer of the Asthma and Allergy Foundation of America, which operates Kids With Food Allergies, agreed. He noted that the current generation of children, teenagers and adults with peanut and other food allergies are still waiting for a cure.

“It is clear that we need a deeper understanding of the causes of food allergy as well as additional research for a food allergy cure. We applaud the work, not only of those who are doing this research, but those who are funding it,” said Dr. Sennett. “At the same time, we must recognize that those critical investments will pay off only in the future. We cannot forget that we still need to keep those currently living with food allergies safe and healthy until a cure is found through ongoing efforts in education, public awareness and advocacy.”

The full text of the study is available at:

http://www.nejm.org/doi/full/1...Moa1414850#t=article