A bold and controversial experiment that showed feeding peanuts to babies and young children could protect them from developing allergies later has shown long-term effects, doctors reported Friday. The children were largely protected a year after stopping peanuts.
After avoiding peanuts for a year, just 5 percent of the children who were given peanuts as babies developed a peanut allergy, the researchers report in the New England Journal of Medicine. That compares to nearly 19 percent of children who didn’t get peanuts as infants.
The findings reinforce guidance from the American Academy of Pediatrics and other groups, which recommend giving children small amounts of peanuts to help avert allergies. For children at high risk because of a family history of allergies, or because they have eczema or other allergies, this should only be done under a doctor’s supervision.
"This study offers reassurance that eating peanut-containing foods as part of a normal diet--with occasional periods of time without peanut--will be a safe practice for most children following successful tolerance therapy," said Dr. Gerald Nepom of the Benaroya Research Institute at Virginia Mason in Seattle.
"The immune system appears to remember and sustain its tolerant state, even without continuous regular exposure to peanuts,” added Nepom, who also heads the Immune Tolerance Network, a research group sponsored by the National Institute of Allergy and Infectious Diseases.
“The findings suggest that children who have regularly consumed peanut-containing foods from infancy to age 5 as a peanut allergy prevention strategy can safely switch to consuming peanut as desired as part of a normal diet,” said NIAID’s Dr. Daniel Rotrosen. “We expect that many will continue to enjoy peanut-containing foods consumed regularly, and others will maintain their non-allergic status with moderate intervals of diminished or no peanut consumption.”
Peanut allergy is serious and it’s received much attention because rates tripled between 1997 and 2008. In severe cases, children can suffer anaphylaxis, a serious and life-threatening reaction. It can take just a small amount of peanut to cause a reaction in an allergic person.
So some schools are peanut-free zones; the Food and Drug Administration requires clear labeling and separation of peanuts in foods; and children learn to carry epi-pens in case they have a reaction.
The original study found that giving peanuts to high-risk infants lowered rates of allergy by 80 percent compared to babies whose parents kept them carefully away from peanuts.
The study team followed 556 of the original 640 children to see if they had to keep eating peanut constantly to stay protected. They don’t.
After 12 months of avoiding peanuts, 4.8 percent of children fed peanuts as babies became allergic to peanuts, compared to 18.6 percent of those who kept away from peanuts from birth.
“The majority of infants did in fact remain protected and that the protection was long-lasting," Dr. Gideon Lack, a pediatric allergist at King's College London who led the study, said in a statement.
“Parents of infants and young children with eczema and/or egg allergy, and so considered high-risk to peanut allergy, should consult with an allergist, pediatrician, or their general practitioner prior to feeding them peanut products."
“For decades, we had been trying to stem the rising tide of food allergy by urging parents to avoid exposing their children to food such as egg, peanut and fish early in life — a recommendation that was based on the idea that early exposure led to allergic sensitization,” Dr. Gary Wong of the Chinese University of Hong Kong, who was not involved in the study, said in a commentary.
“So feed your children and hope that they will eat.”
Lack led another study in which parents were asked to regularly give babies a series of foods that people are frequently allergic to.
Parents of more than 1,300 infants were randomly assigned to either keep all potentially allergy-provoking food away, or to give them some peanut butter, an egg, yogurt, sesame paste, fish and wheat cookies every week. At age 3, 5.6 percent of the children given these foods had an allergy to one or more of them, compared to 7.1 percent of those who didn’t get the food until later — not a significant difference.
But only 40 percent of the parents stuck to the plan, Lack’s team reported, a finding that suggests it’s hard to do. However, adding the foods to a baby’s diet early did appear to be safe and didn’t make them more likely to develop allergies.
“A note of caution — these studies were performed by trained allergists under controlled conditions,” said Dr. Barry Kay, an allergist at Imperial College London.
“What are the correct amounts of foods needed to induce tolerance, and what is the age where it is too late to induce tolerance? There are also issues around the preparation of foods to make them easier for parents to administer. So don’t try this at home yet.”