Early Introduction of Peanut Protects Against Allergy, LEAP Study Finds
Feeding peanut to young infants with heightened allergy risk reduces the odds that a peanut allergy will develop by a remarkable 70 to 80 percent, according to findings in the landmark LEAP study, which were revealed at the AAAAI conference in Houston on Feb. 23, 2015.
This marks a huge breakthrough in the understanding of peanut allergy prevention, and top experts were immediately contemplating actionable steps for doctors and parents.
“We believe the results from this trial are so compelling, and the problem of the increasing prevalence of peanut allergy so alarming that new guidelines should be forthcoming very soon,” wrote Dr. Hugh Sampson, director of the Jaffe Food Allergy Institute at the Icahn School of Medicine at Mount Sinai, and a colleague in an editorial that accompanied the study’s publication in The New England Journal of Medicine.
The British LEAP (Learning Early About Peanut Allergy) study involved 640 “high-risk” babies – defined as those with egg allergy, severe eczema, or both. The infants were assigned to two groups: those whose parents were to regularly feed them peanut and those whose parents were told to have their children avoid peanut altogether. The children, enrolled between the ages of four and 11 months, were given a conclusive peanut food challenge at age 5.
At that age, on average, only 3.2 percent of the “consumption” group had developed a peanut allergy, compared to more than 17.2 percent in the “avoidance” group. (The rate of peanut allergy in the general population is 2 percent, but the babies in the LEAP study were at a higher risk for allergy.)
“There appears to be a narrow window of opportunity to prevent peanut allergy,” said study author Dr. Gideon Lack, professor of pediatric allergy at King’s College London. “As soon as infants develop the first signs of eczema or egg allergy in the first months of life, they should receive skin testing to peanut and then eat peanut products either at home if the test is negative or first under clinical supervision if the test if positive. Infants without such symptoms should be fed peanut products from four months of life.”
(His conclusions were given for physicians; it’s important not to try such steps in a baby with a genetic risk of peanut allergy without first seeing an allergist for advice and testing.)
In the study, peanut protein was usually given in the form of Bamba, a snack food made from peanut butter and puffed corn. For babies not yet able to eat solid foods, Bamba was mashed and mixed with milk or banana. Infants who did not like the snack food ate smooth peanut butter instead.
“This is a doable intervention,” study co-author Dr. George Du Toit, pediatrician and lecturer at King’s College London told Allergic Living. “It’s not like we’re offering a drug that has side effects that people don’t like taking. The kids enjoyed eating this.” He adds that many of the children ended up eating more than the required 6 grams of peanut protein per week.
There were actually two sets of children studied who either consumed or avoided peanut. In the first, 542 babies had negative results to peanut on a skin-prick testing. Even as young infants, a second set of 98 tested as mildly sensitized to peanut. Results from these distinct sets were averaged to arrive at 17.2 percent of allergy found in the avoidance group and the 3.2 percent in the consumption group are averages from these two sets of children.
But the raw data on the two sets is also compelling. In the first (542 babies, negative skin tests), 13.7 percent of the “avoidance” group developed peanut allergy compared to 1.9 percent in the “consumption” group who did not. In the second (98 babies, mildly sensitized), 35.3 percent in the avoidance group became peanut allergic by age 5, compared to 10.6 percent in the avoidance group.
“Early consumption is effective not only in high-risk infants who show no sensitivity to peanuts early on, but it is also effective in infants who already demonstrate peanut sensitivity,” said Du Toit.
Key statistics from the study:
- Involved 640 infants, enrolled when they were between 4-11 months and followed until the age of 5.
- Children in the “consumption” group were asked to eat 2 grams of peanut protein, equal to a heaping teaspoon of peanut butter or two-thirds of a packet of Bamba, three times a week (6 grams total).
- Among the children who originally tested negative for peanut allergy, 13.7% of the “avoidance” group developed peanut allergy by age 5, compared to only 3.2% of the children who ate peanut regularly from an early age.
- 35.3% of the children with positive skin-prick tests (indicating a mild sensitization) who avoided peanuts developed peanut allergy, compared to 10.6% in the sensitized “consumption” group.
- Early consumption of peanut reduced the risk of peanut allergy by 86% for children with negative skin prick tests.
- For mildly sensitized infants, eating peanut regularly from an early age reduced the risk of peanut allergy by 70%.
The American Academy of Pediatrics (AAP) had recommended back in 2000 that children at risk for developing peanut allergy avoid peanuts altogether. However, these guidelines were withdrawn in 2008 as studies began to show that, despite avoidance, the rates of peanut allergy continued to rapidly increase. The LEAP study provides the first comprehensive data clearly showing that early introduction can protect against peanut allergy.
“This study will likely have a significant impact on approaches to prevent the development of peanut allergy in future generations,” said Dr. James Baker, president and CEO of FARE (Food Allergy Research and Education), which co-funded the study along with the National Institute of Allergy and Infectious Disease. “It is also important to note that this study was conducted as a formal, controlled clinical trial, with a well-defined infant cohort to give a definitive answer on the role of early food avoidance in the prevention of peanut allergy,” he says.
While the findings set the medical community and media buzzing, there are key cautions. For instance, the trial did not prevent peanut allergy for everyone in the “consumption” group. “Peanut allergy is not going to go away overnight,” says Lack. “People ought to realize that.”
The investigators are still considering approaches to treat young children whose skin-prick tests indicated they were likely already allergic to peanut. These more sensitized children were excluded from the prevention study.
The study is continuing with the LEAP-On (Persistence of Oral Tolerance to Peanut) study, investigating whether the participants who consumed peanut will continue to remain protected against peanut allergy even if they stop eating peanuts. Researchers also hope to expand the idea of early introduction and investigate whether or not it makes a difference in the development of other prominent allergies, such as milk and egg.