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Medically Clear: Heading Off Peanut Allergy at an Early Age

Ballard, Dustin MD

doi: 10.1097/01.EEM.0000467058.67188.8f
Medically Clear

Dr. Ballardis an emergency physician at San Rafael Kaiser and the medical director for Marin County Emergency Medical Services in San Rafael, CA.





Many summers ago, my wife and I trekked from Mexico to Canada along the Pacific Crest Trail. Fighting off hunger while hiking 20 miles a day was no easy feat. To keep ourselves nourished and upright, we consumed a lot of fatty, filling foods like peanut butter, peanut butter crackers, Snickers bars, and peanuts. (We never, ever got sick of Snickers.) I'm still a huge legume lover, but this sentiment is not shared by all, with good reason.

Peanut allergies have exploded in the past decade — more than doubling in the Western world — with an overall prevalence (or occurrence rate) of three percent in Western countries. Not only are these allergies increasingly common, they can also be deadly serious, and, unfortunately, the affected children rarely outgrow their sensitivity. That is why I find the results of a recent study from Britain so darn exciting.

An international study team called Learning Early About Peanut allergy (LEAP) led by George Du Toit, MB, and Gideon Lack, MB, from King's College in London recently published some potentially game-changing results in the New England Journal of Medicine. The findings build on research previously reported by Du Toit showing that peanut allergy rates were 10 times higher in Jewish children in Britain (where peanut products aren't usually given to kids until after age 1) than Jewish children in Israel, where kids start eating foods with peanuts earlier, at about 7 months. This led to LEAP's hypothesis that introducing peanut-containing products into a baby's diet early could help prevent a peanut allergy.

A total of 640 infants in the LEAP study between the ages of 4 and 11 months were considered “at risk” for peanut allergies because of predetermined sensitivities were randomly placed into one of two groups. The first completely avoided peanut products. The other was introduced to peanut-containing products rather early, the preferred source being a maize-based snack called Bamba. (It looks like a cheese puff and tastes like a peanut.) And let me say, whether you think Bamba sounds tasty or not, these LEAP results pack a wallop that really satisfies.

A total of 13.7 percent of the 530 infants who did not demonstrate any evidence of initial sensitivity to peanuts and who had strictly avoided peanuts (the strict avoidance group) were allergic to peanuts at age 5. By the way, they used repeat skin-prick allergy testing to determine whether a child was allergic to peanuts. Meanwhile, just 1.9 percent of kids who had been introduced early (the consumption group) were allergic to peanuts at age 5. Wow: 13.7 percent versus 1.9 percent. That is a huge difference. Not much likelihood that was a statistical anomaly! In fact, the p-value in the study was less than 0.001.

Among those kids with a previous sensitivity to peanut products, the researchers found that 35.3 percent of kids in the avoidance group were allergic to peanuts at age 5. But just 10.6 percent in the consumption group were allergic to peanuts at age 5. This p-value was 0.004.

This is pretty big news. Being paranoid about peanut exposure in infants could be causing a lot more harm than benefit. The findings are consistent with the hygiene hypothesis in the broader context.

The hygiene hypothesis has been around for a while in different formulations, but can be boiled down to the essential notion that our modern-day hygienic, hyper-clean environment full of antibacterial soaps, hand sanitizers, and disinfecting cleaning products deprives the human immune system of crucial exposures that help it develop properly. There are different levels to this, of course, but it seems that exposure to some good, old-fashioned dirt can help test and strengthen the immune system while also helping to prevent it from going haywire. Kids with pets and kids on farms, for example, are less likely to develop certain immune-mediated diseases like asthma. Fastidiously wiping down surfaces and boiling baby items may be just as detrimental as it is time-consuming, and hygiene seems not be the clear winner that your grandmother insisted it was.

I love the excuse this gives me to cut corners in housecleaning, and my wife is trying to use it to convince me to adopt more furry family members. When it comes time for me to be a grandpa (hopefully that's still a long way away), I know I'll have a lot less angst about giving the babies in my family peanut products before they are a year old. Hopefully we'll see the next generation of infants better protected from deadly peanut allergies by careful, appropriate, and early exposure. And, if anyone out there has a crazy notion to walk from Mexico to Canada, I highly recommend a steady supply of peanut-infused chocolate bars.

You can learn more about this topic by listening to the Medically Clear podcast on iTunes or on Dr. Ballard's website,

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