When It Comes to Allergens—Is It Best to Stay Away?

When it comes to severe food-based allergies, be it citrus fruit or even nuts, doctors have long advised to steer clear for fear that consumption may cause the onset of allergies in children early on. But with a continued spike in the prevalence, and severity, of these allergies in recent years, researchers are now looking to change previously recommended guidelines.

In a new study published this week in The New England Journal of Medicine, researchers investigated the efficacy of current clinical practices as they pertain to the development of allergies. And looking in particular into the more than doubling in the prevalence of peanut allergies worldwide in the last 10 years, the researchers are revealing that avoiding allergens altogether may not be the proper strategy to take in these cases.

"Clinical practice guidelines from the United Kingdom in 1998 and from the United States in 2000 recommended the exclusion of allergenic foods from the diets of infants at high risk for allergy and from the diets of their mothers during pregnancy and lactation" lead author of the study, George Du Toit says. "However, studies in which food allergens have been eliminated from the diet have consistently failed to show that elimination from the diet prevented the development of IgE-mediated food allergies."

"We evaluated strategies of peanut consumption and avoidance to determine which strategy is most effective in preventing the development of peanut allergy in infants at high risk for the allergy."

To best assess which method would address the onset of certain food allergies, the researchers developed a trial known as the "Learning Early about Peanut Allergy" (LEAP) trial, wherein 640 infants were tested until the age of 60 months to see if allergen intervention would be effective in high-risk cases. And by slowly exposing the children to the allergen early on, the researchers were able to reveal a diminished chance of developing a severe allergy later in life.

"Among infants with high-risk atopic disease, sustained peanut consumption beginning in the first 11 months of life, as compared with peanut avoidance, resulted in a significantly smaller proportion of children with peanut allergy at the age of 60 months" Du Toit says. "This intervention was safe, tolerated, and highly efficacious."

"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."

While general avoidance seems to no longer be an effective or suggested recommendation, per the researchers' dual allergen hypothesis parents and physicians should consider exposing children to oral consumption of peanut butter early on-though contact of peanut oils, through the skin still seem to be a serious cause for concern.

"As we have proposed in our dual allergen hypothesis, early environmental exposure (through the skin) to peanut may account for early sensitization, whereas early oral exposure may lead to immune tolerance" Du Toit says. "The LEAP study showed that early oral introduction of peanuts could prevent allergy in high-risk, sensitized infants and in nonsensitized infants."