Peanut allergies in children have skyrocketed to the point that many schools ban foods containing them. Now studies show previous advice is wrong. Rather than keeping kids away from peanuts to protect them, parents should give most infants peanuts from an early age. An allergy expert who is co-author of new guidelines explains.
- Dr. Matthew Greenhawt, Assistant Professor of Pediatrics, Allergy and Immunology Section, Children’s Hospital, Colorado and University of Colorado School of Medicine, and Chair, Food Allergy Committee, American College of Allergy, Asthma and Immunology
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17-07 Peanut Allergies and Kids: Changing the rules
Reed Pence: Over the last 20 years school lunch rooms across the country have been turned on their heads – the old standby peanut butter and jelly sandwich isn’t allowed in many schools that are totally peanut-free. And peanut-free tables are even more common because so many students are literally deathly allergic to peanuts. The number of those students is rising, in the past roughly decade and a half, peanut allergies have tripled and now affect about 2% of all American children. It turns out we’ve brought on some of this ourselves. Back in 2000, new guidelines urged parents to avoid feeding any peanut products at all to very young children; especially those at high risk of allergies.
Dr. Matthew Greenhawt: In kids that were considered high risk for developing allergic diseases and at the time it was considered anybody with two parents that had a history of allergic diseases that, it was recommended that certain foods be delayed. These guidelines, the biggest recommendation was that peanut introduction be delayed until age 3.
Pence: That’s Dr. Matthew Greenhawt, Assistant Professor of Pediatrics in the Allergy and Immunology section of Children’s Hospital Colorado, and the University of Colorado School of Medicine; he’s also Chair of the Food Allergy Committee at the American College of Allergy, Asthma and Immunology.
Greenhawt: In some, for those recommendations, the advice was to avoid until age 3 and that was thought to perhaps shield the child from being exposed to the food too early and developing an allergy against it. You know the immune system might not be ready to tolerate these foods early on and that the early exposure would actually prime the immune system to see them as a danger and can’t develop an allergic antibody against it that upon the next ingestion would lead to a clinical reaction. And this is based on a small study that had supported the delay in introduction, it was done in the mid 90’s at that point, but there was not a ton of data behind that. It was probably more “expert opinion” than clinical trial based data. It was the best information that we had at the time and in the face of what was being recognized as a growing public health problem, the rise of not only food allergies; specifically peanut allergies, the experts who formulated that guideline felt that this was a potentially protective step.
Pence: But even with those guidelines peanut allergies soared. Researches eventually figured out that the theory was wrong – the rules were scrapped in 2008.
Greenhawt: The American Academy of Pediatrics retracted those guidelines more or less and said there is no benefit to delaying the introduction of any foods past 4-6 months of life and the sum of the evidence at that points was not showing there was any benefit and the prolonged delay made any sense. The main change there was, don’t delay past 4-6 months of life but it wasn’t specific to any food like the 2000 recommendations were, so don’t delay anything past 4-6 months of life. But one of the limitations of that guideline was that it didn’t actively recommend when to actually introduce so you have this sort of passive recommendation that says, don’t delay but do this at this age and this at this age and this at that age. Which led to a little bit of confusion.
Pence: Surveys have shown that even with the retraction parents have still been scared of peanuts. And many of them have held back on giving peanut products to their young kids. But now we know that rather than avoiding allergies that helped create them. So now finally new guidelines are out on feeding infants peanut products and they’re pretty much exactly the oppositve of the old ones. Researches now know that the immune system can be trained at an early age, so rather than holding back on peanut products the guidelines urge parents to feed them to kids starting at about 4 months old and keep doing it several times a week from then on. Greenhawt is one of the authors of the new guidelines and he says this time they’re based on solid evidence; a number of studies done of the last 10 years. The first was a British study looking at two groups of Ashkenazi Jewish children.
Greenhawt: Genetically similar Jewish children, one in Tel Aviv and one in London, in the mid- 2000’s. And the observation was that there was relatively little peanut allergy in the Israeli population and there was tenfold more peanut allergy in the UK population. And when they looked and controlled for all the variables that they could, it turned out that the kids in Israel were being exposed to peanut well within the first year of life whereas in the UK, they were following the UK food standards guidance at the time that said – if you’re high risk, avoid until age 3. So, based on that one factor alone in two populations there was a tenfold difference in the rate of allergy. It was a real head-scratcher saying, “Hmm, maybe there is something to this early introduction.”
Pence: However that study didn’t prove that introducing peanuts early was the reason that the Israeli children had ten times less allergies. So, scientists set out to devise a study to do just that.
Greenhawt: They recruited 640 infants and randomized them deliberately, half of them to peanut within the first year of life and the other half to deliberately avoid peanut until age 5. Now these kids were all very very carefully screened; they all had to have severe eczema and/or an existing egg allergy – because those were thought to be the two highest risks for developing peanut allergy – so these kids were brought into the office, they had their introduction and they were told to eat at least 2gm of peanuts, 3x a week, for the next five years. The other group was told to deliberately avoid the peanut for five years. At the end of the five years they brought them back and they found that there was an 80% relative risk reduction between the two groups – the group that avoided had significantly more peanut allergy than the group that was introduced allergy. So, that really confirms what they had observed in the two populations, but this time they proved in a very very well designed clinical trial.
Pence: Yet another study has found that in infants with no risk factors had fewer peanut allergies if they were introduced to peanuts at 3 months old, rather than 6 months. So it’s clear that there’s a window of time where the immune system can be trained.
Greenhawt: The timing, the specific timing of introduction, there is this critical window where you can expose the body to a potential allergen and they don’t react – somehow the immune system learns to tolerate it. To be compatible with sort of human physiology on an evolutionary perspective, you’re not supposed to react to these foods that have great sources of protein and other nutrients that are readily available and tasty. Its unfortunate that we haven’t quite figured out WHY a small percentage of the population DOES react to these foods, but we’re learning more and more and this is a huge piece of the puzzle that these kids, with these risk factors, if you expose them early enough – you can prevent peanut allergy from developing in a significant amount of them. So that’s just fantastic.
Pence: Doctors can predict which children are most likely to develop a peanut allergy and Greenhawt says they deserve special care under the guidelines. There are infants who already have a skin condition that makes them prone to other allergies such as hay fever.
Greenhawt: The main criteria I think that is most applicable for the U.S. population will be eczema and the main risk criteria are those kids with severe eczema. These kids should be well identified by the time they were moving into this window where food should be introduced. So, this is not eczema that develops sort of a week ago and went away with a little moisturization or even a one time dose of an over the counter topical steroid – this is severe and persistent eczema that has failed to respond to frequent bathing, good moisturization and escalating doses of topical steroid. It’s probably been present since very very early on in that child’s limited life span at that point of time and it’s more than likely a problem that the parents are certainly well aware of and hopefully their doctor is also well aware of, so the severe eczema kids should be well identified.
Pence: Egg allergy is another criterion, but most infants aren’t introduced to egg until they’re around a year old – so eczema is the main red flag. The peanut guidelines say that parents of those children should think about talking to their pediatrician at their child’s 4-month check up.
Greenhawt: This is a point in time where normally the doctor starts talking to the parents about transitioning away from primarily breast or bottle feeding and saying, “this is what we’re gonna start introducing solid foods over the next couple of months,” and you give them the anticipatory guidance about trying green cereals or fruits and vegetables, we still want that to occur, that absolutely has to occur. However, the change here now is that we would like peanut in these kids with either severe eczema and/or egg allergy as early as 4-6 months of life, after they’ve tried and tolerated at least a few foods and have gotten used to the taste and texture and the coordination of solid foods. That’s the ideal time for these children to be introduced to peanuts. Now, because of the leap study and the data in the leap study it was felt that these kids with sever eczema and/or egg allergy were at the highest risk and it was thought that a little bit more of a cautious approach be taken with them. So these kids are recommended to be referred to an allergy specialist for further testing.
Pence: If a skin test for peanut comes back very positive, they already have an allergy and shouldn’t get peanut products at all – that’s a very small number of kids. Those with a mild to moderately positive result should have peanut introduction done at the doctor’s office to be safe, but their allergy can still be staved off. The great majority of kids though have much less to worry about – Greenhawt says the child can go home and have peanut product introduced there.
Greenhawt: So those kids, around 6 months of life, the recommendation is – after you’ve had a couple of solids introduced, to go ahead and introduce peanut containing products – and this can be done at home. So they don’t need the extra caution per se – if the family is concerned and they’re seeking referral, if the doctor taking care of that child has a concern – obviously go ahead and refer, that’s what the allergy specialist are there for. But by and large, these kids are not recommended to necessarily have to go to a doctor to have this introduction medicalized and it can be done at home. And the guidelines actually include a number of different recipes for peanut containing foods. I think one of the important points is, people are hearing “peanut” but not “peanut containing;” a kernel of peanut is an absolute choking hazard for a child that age – actually any child under the age of 4 should not be exposed to a whole kernel of peanut. So we’re talking about peanut containing products, so baby puffs that contain peanut, thinned out smooth peanut butter, or other appropriate forms where the peanut is exceptionally well ground up or not in the form where the child could choke.
Pence: Greenhawt admits that some parents are concerned about the safety of the whole thing; after all we’ve spent the last two-decades hearing how we should keep peanuts away from our kids. But he says, there’s reason to be confident.
Greenhawt: This won’t stop all cases of peanut allergy outbreak, there’s still going to be cases – some kids who might react at home and some kids might react under the doctor’s supervision. What you can be reassured about from the baseline studies, were the reaction that did occur were actually very few in number and those that did occur were very mild – they all were mainly limited to the skin. I think people are afraid and there’s a little bit of folklore that sort of that first bite is gonna be a severe, potentially fatal, reaction. It’s impossible to predict that, but if you look at the studies in infants – and this has been proven not only in the study from the UK, but if you look at the Australian experience – where they did a large scale population based study of giving kids peanut around age 1; in that scenario most of those reaction were also mild and limited to skin.
Pence: After that Greenhawt says simply, keep it up.
Greenhawt: We would like the parents to give this to them frequently, a couple of times a week. In the guidelines there’s a recommendation for – aim for a gram, 3x a week – if you can do that, great; if you can’t, don’t worry; give it to them often, hopefully they’ll like the flavor. It’s got a lot of protein and a lot of other nutritional value and hopefully it’s a snack that these kids will enjoy.
Pence: Greenhawt admits that the complete turnaround in guidelines has slowed their adoption, but if parents act on the new rule, someday a peanut-free school will be a little less common.
Greenhawt: I think the potential is enormous, I think we’re looking at tens of thousands of cases prevented in the best-case scenario each year. You think about, there are 4 million born each year approximately in the United States and upwards of 20% of them might have eczema and up to 2% might develop egg allergy, so I mean, that’s a lot. And every case counts, obviously, the more the merrier and we’re hoping that on a population level this will make a major impact but I do think the potential is in the order of tens of thousands case a year, which would be fantastic.
Pence: With parental buy-in he says, the rise in peanut allergies could be reversed. You can see the guidelines on the website of the American College of Allergy, Asthma and Immunology at ACAAAI.org. You can find out more about all of our guests on our website, RadioHealthJournal.net. I’m Reed Pence.
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