In recent years, experts have argued for a harmonized, risk-based approach to allergen labeling on food products—especially precautionary allergen labeling (PAL)—which would require the acceptance of reference doses for risk-based action levels to determine when allergen labeling should be applied. Reference doses are based on the lowest doses of allergens in a food predicted to cause an allergic reaction in a certain proportion of the allergic population.

To support decision-making and acceptance of harmonized reference doses for PAL, a new study published in Food and Chemical Toxicology has demonstrated that the use of PAL based on internationally recommended reference doses could protect allergic people while likely only eliciting non-severe reactions in a small proportion of the allergic population.

Problems With PAL and Efforts to Harmonize Allergen Labeling

Traditionally, food allergen labeling has followed a precautionary hazard-based approach, in which food products are labeled with warning statements when even the slightest possibility of allergen contamination is present, potentially limiting consumer choice and lacking clarity. Moreover, voluntary PAL is a tool meant to protect allergic consumers from accidentally eating foods containing undeclared allergens that may cause a reaction, but experts believe that the overuse and inconsistent application of PAL may have eroded its risk communication efficacy.

Recently, in an effort to promote harmonized allergen labeling, the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) published a framework for risk-based labeling of priority allergens, establishing threshold levels and reference doses for different allergenic foods. A previous study by researchers from Laval University and Health Canada predicted that the use of threshold levels for PAL recommended by FAO/WHO could greatly reduce the allergic risk posed to Canadian allergic individuals, especially for certain high-risk allergens like milk and egg.

Additionally, in the Netherlands, the use of PAL is limited to products for which the allergen risk has been assessed; however, this type of directive does not apply to the rest of the EU—even though the European Court of Auditors has found that precautionary labels are frequently inaccurate. European scientists have called for harmonized food allergen regulations at the EU level, which is currently hindered by differences between European laboratories in the reference doses and portion sizes used when monitoring allergens in food.

Study Shows Recommended Doses for PAL Would Only Elicit Mild to Moderate Reactions

The new study published in Food and Chemical Toxicology analyzed the reactions of allergic people to foods containing 11 priority allergens at FAO/WHO-recommended doses. Using a database of individual threshold data from low-dose food challenge studies in allergic patients, which were collected by the Netherlands Organization for Applied Scientific Research (TNO) and the University of Nebraska—Lincoln’s Food Allergy Research and Resource Program (UNL’s FARRP), the researchers analyzed more than 1,000 double-blind, placebo-controlled food challenges for the 11 allergenic foods. Frequency and severity of allergic reactions were observed at and below doses to which a maximum 10 percent of the allergic population is predicted to have a reaction (ED10), as described by FAO/WHO recommendations.  

The analysis showed that, at ED10, an average of one to two symptoms were noted per allergic individual, most of which (68 percent) were subjective symptoms that affected the skin (60–71 percent; e.g., flushing and erythema), followed by symptoms affecting the eyes/nose (e.g., stuffy nose, red eyes, and lip swelling). Very few of the symptoms (5–8 percent) were gastrointestinal or respiratory (vomiting or coughing). Only two symptoms classified as severe, specifically wheezing and laryngeal edema, were recorded, at approximately ED08 levels.

Based on their findings, the researchers conclude that PAL based on FAO/WHO-recommended ED05 threshold levels for priority allergenic foods would be widely protective, resulting in only mild to moderate symptoms that are expected to resolve without medical attention, in a small proportion of the allergic population.

The study’s authors include W. Marty Blom, Ph.D. and Geert F. Houben, Ph.D. of TNO and Utrecht University Medical Center; Joost Westerhout, Ph.D. of TNO; Thuy-My Le, M.D., Ph.D. of Utrecht University Medical Center; and Steve L. Taylor, Ph.D. and Joseph L. Baumert, Ph.D. of UNL.