True food allergy prevalence rates are limited by consistent definitions and methods of diagnosis, according to recently published research by a University of Colorado School of Medicine scientist.
Carina Venter, PhD, RD, professor of pediatrics, is co-author of a recent article published in The Lancet Gastroenterology & Hepatology, reporting that the lack of widespread food allergy research using validated measures could be skewing the numbers.
“It may be that food allergies are on the rise, but establishing prevalence is limited by what defines food allergies, and how we diagnose them,” Venter says.
Prevalence remains stable
For the article, Venter reviewed cohorts of children born on the Isle of Wight, an English Island. The study indicated no significant increase in milk, egg, or other food allergies between cohorts — one in 1989-90, the other in 2001-02.
In the U.S., data largely comes from self-reported food allergies. However, no nationwide prevalence study based on oral food challenges exists.
As a result, there is no consistent, authoritative source of information to determine whether food allergies are becoming more prevalent.
“Nobody likes that finding, and they even question it,” Venter says. “People believe food allergies are escalating, and this is probably also our clinical impression.”
The processed food problem
If food allergies are increasing, diet could be part of the reason, according to Venter, who points to ultra-processed foods, low in natural microbial content and high in additives like emulsifiers that can damage the epithelial barrier of the gut.
“When you eat emulsifiers, in the gut, they become like soap which destroys the epithelial layer of the gut, so that allergens can actually cross the gut wall,” Venter says.
According to Venter’s findings, children who eat more ultraprocessed foods are more likely to develop allergies, though genetics and other environmental factors may also play a role. No one single factor has been identified to explain the development of allergies.
Venter’s advice to consumers? Focus on fresh as far as possible to at least reduce the risk of developing allergies.
“Cook fresh food at home whenever you can and pack a lunchbox with fresh foods.” Venter says. “It’s more beneficial for your health.”
From avoidance to tolerance
Venter is leading innovation in allergy management, moving from strict avoidance toward a medically supervised reintroduction of food allergens using a food ladder approach.
Using the ladder approach for milk and egg, children start with ingesting small amounts, and over time, increasing gradually under medical supervision.
The results can be significant, Venter highlights, noting that in Ireland, virtually no child over age three to five still has a milk allergy, due to early use of the milk ladder approach.
Through her research, Venter hopes that ladder therapy will become a standard to diagnose food allergies.
“We could be the world leaders in ladder therapy,” Venter says. “It’s not just about taking allergens out. It’s about expanding what’s left, adding variety, building tolerance, and helping families cook healthy meals together.”
The definition dilemma and proper diagnosis
Food allergy is an umbrella term covering two types of adverse reactions to food:
- IgE-mediated food allergies, which occur within two hours of ingestion — with symptoms like swollen lips or hives.
- Non-IgE-mediated food allergies, which occur from around one hour of ingestion to days or even weeks later — often presenting as gastrointestinal and perhaps cutaneous symptoms which can be difficult to define and diagnose.
While researchers agree that IgE-mediated and non-IgE-mediated adverse reactions constitute food allergy, additional research is needed to determine whether gut and/or skin-related immune reactions meet the definition of food allergy.
Along with finding a proper definition, another limitation is verifying if someone has a food allergy.
“For IgE — the immediate type allergies — we can do skin tests, and we can do blood tests, and those tests may only be about 40-50% accurate in some patients depending on the clinical history,” Venter says. "For the delayed non-IgE-mediated food allergies, there is currently no test available.”
For most non-IgE-mediated food allergies, diagnosis is made by avoiding the food for a period of time, followed by reintroduction. Such research, however, is still in its infancy and much more study is required before either diagnosis or treatment based on non-IgE immune responses can be incorporated into routine practice.
