The Nuts and Bolts of Peanut Allergy

The Nuts and Bolts of Peanut Allergy

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By: Meital Yerushalmi

The Addendum Guidelines for the Prevention of Peanut Allergy in the United States, published in January 2017, have illustrated that our understanding of peanut allergy (PA) has come a long way.1 Endorsed by the American Academy of Pediatrics (AAP) and the Canadian Society of Allergy and Clinical Immunology, the new guidelines recommend early introduction of peanut protein for infants, particularly those with an increased risk for PA*.1 Yet, my mission to unravel just how far these guidelines have come from their predecessors in the past two decades has, surprisingly, sent me on a trip down memory lane.

I grew up in a small desert town in Israel and moved to Canada as a teenager in the mid-2000’s. It was then when I first built a snowman, tried real Canadian maple syrup, acquired a taste for Tim Horton’s coffee, and got my own Team Canada hockey jersey. It was also the first time in my life that I learned about an allergy to peanuts. Peanut allergy is quite rare in Israel, insofar as I had neither met nor heard of anyone living with this life-threatening hypersensitivity prior to moving to Canada.

For years I was perplexed about the striking difference in the rates of PA between the two countries. Several visits to local Jewish schools in Toronto, featuring allergy alerts and peanut-free zones, suggested that genetics alone are not the answer to this conundrum. Could, then, cultural differences be at play?

A 2008 study aimed to answer this question, and revealed that the prevalence of PA among Jewish children in the UK is ten-fold higher than that of their Israeli counterparts.2 As the two groups have a similar genetic background, investigators hypothesized that their findings may have resulted from differences in the children’s peanut consumption. Indeed, while UK parents were advised to avoid introducing peanuts to infants in the first year of life,2 echoing the AAP 2000 guideline recommendation to delay their introduction in high-risk children until three years of age,3 Israeli parents provide them peanut products liberally during that time.

Peanuts are undoubtedly popular in Israel, commonly in the form of Bamba–an iconic peanut snack considered a staple of Israeli childhood. Bamba Baby, its mascot, speaks to its popularity among children (though, as my Israeli friends can attest, we still pick it up for ourselves in the Kosher aisle from time to time…). Could Bamba be at the cornerstone of tackling the growing rise in PA in North America?

Recent updates to the guidelines suggest that this may be the case. Whereas the 2008 AAP guideline rescinded the peanut avoidance advice, concluding that no convincing evidence supported a significant protective effect by delayed peanut introduction beyond four to six months,4 current guidelines go further by promoting early peanut consumption in high-risk infants.1 These new guidelines are based primarily on the results of the Learning Early About Peanuts (LEAP) trial,5 in which 640 high risk* infants, ranging from 4 to 11 months of age, were randomized to ingest or avoid peanuts until age five. An oral peanut protein challenge at that point revealed that 17.2% of children in the avoidance group exhibited a PA, as compared with only 3.2% in the consumption group.5 In other words, early introduction of peanuts in high-risk infants was shown to prevent PA. Furthermore, a follow-up study reported a persistence of Oral Tolerance to Peanut (LEAP-On) among children in the consumption group following a 12-month avoidance period.6 Given that PA is the leading cause of death due to food-induced anaphylaxis in the US, the implications of such findings cannot be underestimated.7

As for Bamba, on my visit home in June I learned of some of its new variations–filled with Halva (sesame), hazelnut, or almond cream–evidently, we Israelis go nuts for peanuts.

*Infants with severe eczema and/or egg allergy

Infants with mild to moderate eczema

Children with a first-degree relative who suffers from an allergy

 

References

  1. Togias A, Cooper SF, Acebal ML, et al. Addendum guidelines for the prevention of peanut allergy in the United States: Report of the National Institute of Allergy and Infectious Diseases-sponsored expert panel. Ann Allergy Asthma Immunol. 2017;118(2):166-73.
  2. Du Toit G, Katz Y, Sasieni P, et al. Early consumption of peanuts in infancy is associated with a low prevalence of peanut allergy. J Allergy Clin Immunol. 2008; 122(5):984-91.
  3. American Academy of Pediatrics Committee on Nutrition. Hypoallergenic infant formulas. Pediatrics. 2000;106(2 Pt 1):346-9.
  4. Greer FR, Sicherer SH, Burks AW, et al.. Effects of early nutritional interventions on the development of atopic disease in infants and children: the role of maternal dietary restriction, breastfeeding, timing of introduction of complementary foods, and hydrolyzed formulas. Pediatrics. 2008; 121(1):183-91.
  5. Du Toit G, Roberts G, Sayre PH, et al. Randomized trial of peanut consumption in infants at risk for peanut allergy. N Engl J Med. 2015; 372(9):803-813.
  6. Du Toit G, Sayre PH, Roberts G, et al. Effect of Avoidance on Peanut Allergy after Early Peanut Consumption. N Engl J Med. 2016;374(15):1435-43.
  7. Bock SA, Munoz-Furlong A, Sampson HA. Further fatalities caused by anaphylactic reactions to food, 2001-2006. J Allergy Clin Immunol. 2007;119(4):1016-8.