For years, the advice to parents worried about food allergies has focused, for reasons that make intuitive sense, on avoidance. After all, if kids don’t eat common allergens like peanuts, dairy or eggs, they can’t have a bad reaction to them.
But research shows that’s not how the immune system works. And in fact, the opposite tactic–exposing kids to possible trigger foods–may be wiser. A breakthrough study published in the New England Journal of Medicine found that both allergic and nonallergic infants who ate small amounts of peanuts had a much lower rate of allergy than those who avoided nuts altogether for five years. The key is to start early.
To come to this conclusion, researchers found 640 infants with eczema and egg allergies. Because their immune systems were already primed to react to antigens, some already tested positive for peanut allergies while others were more likely to develop them. But if they ate small, carefully monitored amounts for five years, they had an 86% lower chance of developing the allergy than those who avoided nuts did.
As it stands, leading medical groups no longer tell parents to avoid giving babies nuts, based on evidence that small amounts can train an allergic kid’s system to react more mildly to the offending ingredient. But these are the first results to show that it may be possible to prevent the allergy altogether.
The reason may rest in the gut. When digested, peanuts are more likely to be accepted as a food, while peanut residue via the skin–delivered, say, by a mom’s kiss–may be registered as a threat, triggering an allergic reaction.
It’s too early to give concrete advice on the basis of these findings, but for now it looks like the best medicine for peanut allergies may, in fact, be nuts themselves.
This appears in the March 09, 2015 issue of TIME.