FAO/WHO Expert Committee addresses the complexities of food allergens levels

With the objective to determine the amount of food allergens that can represent a risk to allergic individuals, the joint ad hoc FAO/WHO Expert Consultation on Risk Assessment of Food Allergens convened the second in a series of meetings on food allergens addressing “How much is too much?”

While some allergic individuals don’t react to low doses of food allergens, others experience tingling or itching sensations and few may even have severe reactions. A worrying one is the rare, but potentially life-threatening anaphylaxis. As part of an ad hoc Joint FAO/WHO Expert Consultation on Risk Assessment of Food Allergens, experts with collective wisdom from the realms of immunological research, academia, the private sector, government and clinical practice met to establish amount or level of several priority food allergens that are not expected to result in appreciable health risks among the majority of consumers.

Consensus was obtained that the Reference Dose (RfD), an index or range of the highest amount of allergen that does not cause even a mild objective allergenic symptoms among a proportion of allergenic patients, should be health-based and conform with the established definition of health-based guidance values. In contrast to approaches used previously, experts at this meeting concurred that an advanced statistical approach the “benchmark dose/probabilistic hazard assessment approach” was best suited to establish Reference Doses (RfD) for this meeting.  

With an approach to determine the RfD agreed upon, the experts then focused their attention on the amount of allergen that would cause noticeable clinical response in a specific fraction of the population, for example, reactions in five or one percent of exposed allergenic individuals. These levels of allergen are known as the population-based eliciting doses (EDs), and may be expressed as the ED₀₅ or ED₀₁, as those doses causing reactions in five or one percent of the population, respectively. To establish these numbers, the committee relied on clinical data from studies with allergic patients, and the most up-to-date scientific literature to refine their assessment.

When the health-based consequences of establishing thresholds based EDs was explored, an important conclusion was drawn: Although the total number of mild to moderate illness was predicted to be different if an ED₀₁ or ED₀₅ was chosen as threshold, the number of expected severe anaphylactic reactions did not change. Therefore, the experts determined that using the ED₀₅ was an appropriate threshold to protect the greatest number of consumers anaphylaxis.

The knowledge of thresholds constitutes a critical requirement to assessing the risks from allergens. Determining thresholds is also essential for evidence-based application of risk management and mitigation strategies. Using these updated approaches and taking into consideration the most recent literature, and a broader scope of data than what was previously available, this work represents an advance in the understanding about the doses of food allergens that result in disease. Importantly, the approach used can be applied to conduct quantitative risk assessments for new or emerging allergens or other allergens not reviewed in this meeting that are prevalent on national or regional scales. This work specifically contributes to scientific evidence upon which recommendations can be made to help protect individuals from severe food-associated allergenic reactions.

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