Peanut Allergy Prevention: Research Update

The first 5 years may be the time offer peanut to prevent allergy.. Chad Springer/Getty Images

If you have a child with food allergy, you’ve probably asked yourself (a million times!) if there was anything you could have done to prevent the development of food allergies. I know I asked myself that question after my son was diagnosed with a tree nut allergy.

While there are some well-researched strategies for preventing food allergies in young children, such as not offering solid food to babies before 4 months of age, researchers are continuously looking for ways to manage food allergies better, and are investigating how to reduce the incidence of food allergies, and perhaps even cure it.

The most recent study, appearing this past February in the New England Journal of Medicine and conducted in the UK, looked at the prevention of peanut allergy in infants who were at high risk for developing peanut allergy.

The authors studied 640 infants between ages 4 and 11 months with severe eczema, egg allergy or both. They divided the babies into two main groups using a skin-prick test before the study: one group of babies were sensitive to peanut extract (evidenced by a wheal: a small, raised, swollen bump on the skin) or not sensitive to peanut extract (no wheal after skin-prick test). Then, the infants were randomly assigned further into two groups: babies that were able to “eat peanuts” or who had to “avoid peanuts” until 60 months of age (5 years old).

The goal of the study was to determine the proportion of participants who would develop peanut allergy at age 60 months. Babies in the “eat peanuts” group, who were not initially sensitive to peanut extract, ate 6 grams of peanut protein per week contained in a snack called Bamba (a puffed peanut butter finger food).

The findings: among 530 infants who were not initially sensitive to the peanut extract, 13.7% of them developed a peanut allergy in the “avoid peanuts” group, and 1.9% of the infants developed peanut allergy in the “eat peanuts” group.

Of the 98 babies who initially tested positive to peanut extract, the prevalence of peanut allergy at age 60 months was 35.3% in the “avoid peanuts” group and 10.6% in the “eat peanuts” group.

  In the “eat peanuts” groups, the levels of peanut-specific IgG antibody increased, while the “avoid peanuts” groups showed evidence of elevated peanut-specific IgE antibody. A lower ratio of IgG to IgE antibodies was associated with peanut allergy.

The researchers concluded that the early exposure to peanut in the first 5 years of life significantly decreased the occurrence of peanut allergy--by 86% in those infants who were not sensitive to peanut extract and by 70% in those infants who were positive in their skin-prick test at study entry-- in children who were at high risk for peanut allergy.

Of course, the results of this study are very interesting and shed light on the lower incidence of peanut allergy in other countries, particularly those countries where peanut is part of the infant diet. However, many questions remain.

In the meantime, experts in food allergy management have provided some interim guidelines, especially for those children who may be at questionable risk for peanut allergy, in an editorial comment in the New England Journal of Medicine:

“… we suggest that any infant between 4 months and 8 months of age believed to be at risk for peanut allergy should undergo skin-prick testing for peanut. If the test results are negative, the child should be started on a diet that includes 2 g of peanut protein three times a week for at least 3 years, and if the results are positive but show mild sensitivity (i.e., the wheal measures 4 mm or less), the child should undergo a food challenge in which peanut is administered and the child's response observed by a physician who has experience performing a food challenge. Children who are nonreactive should then be started on the peanut-containing diet.”


Preventing peanut allergy through early consumption: Ready for prime time?

Du Toit et al. Randomized trial of peanut consumption in infants at risk for peanut allergy. N Engl J Med. 2015.

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