Peanut butter is to childhood as beer is to frat parties, but common practice for avoiding peanut allergies has been to keep some kids from eating the popular legume and its various products.
But an impressive new study has shown that the opposite behavior — early, regular exposure to peanuts — might help wee ones avoid the allergy after all. Published in the New England Journal of Medicine (NEJM), the research, according to its lead author showed “an 80% preventive effect” from a study with “an extremely rigorous design,” as reported by MedPageToday.com.
Among the subjects who had a negative result on a skin-prick test for peanut allergy when they were 4 to 11 months old, nearly 14 in 100 who avoided peanuts had become allergic by the time they were 5 years old. But only about 2 in 100 subjects who regularly ate peanuts became allergic.
And among the kids who had a positive skin-prick test, more than 1 in 3 who avoided peanuts were allergic at age 5, compared with about 1 in 10 who had consumed peanuts or peanut products.
Still, the NEJM was cautious: "The question of whether early exposure or avoidance is the better strategy to prevent food allergies remains open," the authors wrote. But elimination diets consistently have not prevented allergies, so even though strict avoidance of the suspected food has been standard practice, this study really questions the wisdom of that approach.
Earlier research hinted at the new results. Jewish children living in Britain who seldom ate peanut products early in life had 10 times the rate of peanut allergy than their Israeli counterparts, who been given peanut products when they were about 7 months old. Those researchers thought that maybe early exposure reduced the likelihood of the allergy developing, MedPageToday explained, so they designed the NEJM study, Learning Early about Peanut Allergy (LEAP), to test the hypothesis.
From 2006 to 2009, 640 infants who were considered to be at high risk for developing peanut allergy because they already had severe eczema or egg allergy were studied. They all got an allergy skin-prick test; 530 were negative (that is, indicating no allergy), and 98 who had a reaction as large as 4 mm in diameter were considered to have a low-positive test. Children who reacted with a skin mark larger than 4 mm were excluded from peanut exposure for safety concerns, as they were considered too high risk to test further.
So the caveat here would be that if your child shows a definite, significant sensitivity to peanuts in a preliminary test, it’s best not to give him or her peanut products. The exposure-as-defense, per this study, applies only to kids with no or only minor risk of allergy.
When the kids remaining in the study were 5 years old, they were given peanut products to eat. Adverse events that occurred more often in the consumption group included upper respiratory tract infections, gastroenteritis (digestive problems), skin infections, rash and conjunctivitis (pink eye), but most were mild or moderate.
Peanut allergies have quadrupled in the last 13 years, so the LEAP results are compelling, and some allergists/immunologists advocate developing new guidelines to address them. As the NEJM author said, "Soon after weaning peanuts should be added to the diet,” except for high-risk infants (including those with severe eczema), for whom skin-prick testing is required.
What if your child already is allergic? That’s tricky these days, when some schools even prohibit kids from bringing peanut butter from home. As Dr. Jeffrey M. Drazen, editor-in-chief of the NEJM said in a media briefing, "We've figured out how to prevent and lower the incidence of peanut allergy, but we already have a bunch of kids who are allergic to peanuts. How are we going to help kids get their peanuts early while not contaminating those children with peanut allergy. It's going to be a tough problem for the PTA.”