Published online: July 15, 2019
Peanut allergy causes severe and fatal reactions and the current standard of care is safe avoidance of the allergen. Allergic individuals rely on clear labelling to protect them, however current precautionary allergen labelling which advises on accidental peanut contamination is confusing and poorly represents risk. In part this is due to a lack of agreement over the threshold amount of peanut which causes allergic reactions as a well as a paucity of data on how these thresholds are affected by everyday cofactors such as sleep deprivation and exercise.
In a recent article published in The Journal of Allergy and Clinical Immunology (JACI), Dua and colleagues estimated peanut threshold doses for a UK peanut-allergic population and examined the effect of sleep deprivation and exercise. They gathered data on 100 peanut allergic individuals in a multicentre crossover study based in Cambridge and London, UK. Participants underwent blinded challenge to confirm their peanut allergy followed by three open peanut challenges: one when exercising, one when sleep deprived and one with no intervention, which was used as a comparator for the intervention challenges. Food challenges were performed in a random order. The researchers analysed the threshold dose of peanut protein triggering allergic symptoms in the non-intervention challenge compared to each intervention challenge. Dose distributions were modelled to estimate doses which would elicit a reaction in various proportions of the peanut-allergic population, in order to help guide reference doses for the food industry.
The authors found that the average threshold dose of peanut protein required to trigger an allergic reaction was 214 mg, roughly equivalent to one peanut. Both exercise and sleep deprivation independently and significantly lowered this threshold dose by 45%. The mean dose estimated to elicit a reaction in 1, 5 and 10% of the peanut allergic population without these co-factors was 1.3 mg (95% CI: 0.8 -2.0), 3.8 mg (95% CI: 2.4 -5.7) and 7.0 mg of peanut protein (95% CI: 4.5,10.5), respectively.
These findings suggest that exercise and sleep deprivation each decrease the reaction threshold by approximately half. This reduction in threshold needs to be accounted for when defining reference doses for food labelling and when advising patients about the impact of co-factors in situations such as immunotherapy.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.