Eat Nuts to Curb Nut Allergies?
Seattle’s Colin Wenrick shares no-longer-taboo peanut candies with his twin sisters.
Photo: Joshua Huston
It’s clear that babies learn a great deal within the first few months of life. They begin babbling and imitating sounds, will grasp and shake small toys, sit up, and roll around. And it turns out their immune systems are getting smarter, too.
We’ve learned how the immune system begins to discriminate between safe and unsafe foods, says Dr. Jerry Nepom, director of the Immune Tolerance Network, which is led by Seattle’s Benaroya Research Institute at Virginia Mason Hospital. “That goes on during the first months of life. The immune system educates itself so it can defend itself later on.”
Research suggests that the perfect time to introduce a baby to a potential allergen like peanuts is while the immune system is still learning. Contrary to earlier advice, exposing babies to peanuts instead of avoiding them can prevent nut allergies.
A study published this spring in the New England Journal of Medicine also found that once the immune system figures out that peanuts are OK, it won’t forget.
The research was led by Dr. Gideon Lack, a London-based allergist who conducted the LEAP (Learning Early About Peanut) allergy study, which ended in 2014. Tracking children over the course of four years, Lack found that infants who consumed peanuts were 80 percent less likely to develop a peanut allergy compared to those in his control group. The participants were children at greater risk of having a peanut allergy due to severe eczema, an egg allergy, or both.
Lack’s team then wondered what happens to this immunity if a child simply doesn’t like peanuts and has no interest in consuming them. Nepom led the multidisciplinary advisory board that helped design and conduct Lack’s most recent trial, called LEAP-On, which aimed to find out what would happen if the LEAP participants stopped eating peanuts together.
LEAP-On followed 550 of the original 628 LEAP kids, roughly half of whom had had early exposure to peanuts. All of the children, who were at that point 6 years old, stopped eating peanuts for a year.
The results showed that avoiding peanut consumption for a year did not cause the allergy to develop, Nepom says, adding, “Whether longer periods of avoidance will cause tolerance to decline is not yet known, but we have plans to investigate this further.”
The new medical guidelines, Nepom says, recommend early introduction to peanuts using peanut butter or peanut flour, starting with infants as young as 4 months, provided there is no family history of eczema or atopic dermatitis. Since these skin disorders often are associated with peanut allergies, babies with family members who suffer from these ailments are advised to take their first taste of peanut flour in a doctor’s office. (Children shouldn’t eat whole peanuts or other whole nuts until at least 3 years old due to the choking hazard.)
Peanut allergies are not the most common allergen for kids (that title goes to eggs, a less dangerous allergy that is often outgrown), but they are the most serious. Not only is a peanut allergy life-threatening, but sufferers are at risk even in the vicinity of peanuts.
Using the findings from the LEAP-On study as a basis, Nepom has expanded his research to kids who already have peanut allergies.
“We have quite a few ongoing studies that aim to figure out how to reverse the peanut allergy and make it safe for the kids who are already allergic. Everything we’ve learned from the prevention study will help us develop new therapies for kids who already have the allergy. It’ll take a couple years, but there will be a big payoff,” he says.
Nepom also is preparing a study to investigate whether the peanut strategy is effective for other allergens, specifically milk and eggs. He expects the research to begin by the end of this year and involve working with experts worldwide.