Christopher Warren, PhD, on Whether Sesame Should Be Considered a Top Food Allergen

The US burden of immunoglobulin E (IgE)-mediated sesame allergy is higher than previous estimates suggested, according to a new JAMA Network Open cross-sectional study.¹ Furthermore, the data also indicate that this condition is likely underrecognized by US policy makers and underdiagnosed by physicians.¹

The study may inform pending regulatory action by the US Food and Drug Administration (FDA), which is evaluating the potential addition of sesame allergy to the list of top food allergies. Consultant360 discussed the clinical and public policy implications of these findings further with first author Christopher Warren, PhD, from the Center for Food Allergy & Asthma Research, Northwestern University Feinberg School of Medicine, and Ann & Robert H. Lurie Children's Hospital of Chicago.

C360: What important background knowledge or statistics informed this research?

Dr Warren: The US Food and Drug Administration (FDA) is currently considering regulatory action that would add sesame to the list of food allergens for which mandatory labeling is required on packaged foods.² Last year, the FDA issued a “request for information on the prevalence and severity of sesame allergies in the United States”, which would inform any new regulations. In contrast to other countries, such as the European Union, Australia, and Israel, current US law does not require allergen labeling on sesame-containing products. 

Notably, on July 26th, 2019, Illinois Governor J.B. Pritzker signed HB2123, a law which now mandates that any packaged foods for sale in Illinois indicate the presence of sesame on their labels.³ The bill was sponsored by IL State Representative Jonathan Carroll (D-Northbrook), whose daughter is sesame-allergic and has had difficulty avoiding sesame when eating out.³

C360: How was the study conducted?

Dr Warren: Our research team, led by Ruchi S. Gupta, MD, MPH, administered a survey via telephone and web to over 50,000 US households. The survey asked respondents to supply detailed information about any suspected food allergies, including specific allergic reaction symptoms, details about clinical diagnosis of food allergies, and demographic information. We obtained responses for a nationally-representative sample of 78,851 US children and adults.

Consultant360: What were the key findings from your study?

Dr Warren: More than 1.5 million US children and adults (0.49% of the US population) report current sesame allergy, and over 1.1 million (0.34% of the US population) either report a physician-diagnosed sesame allergy or a history of sesame-allergic reaction symptoms that are consistent with an IgE-mediated response. This is a greater burden of sesame allergy than acknowledged by previous research.

Milk and egg allergies often develop early in life and are outgrown by adolescence. However, although sesame allergy affects children and adults to a similar degree, evidence suggests that sesame allergy is less often outgrown. Furthermore, our data indicate that every 4 in 5 patients with sesame allergy have at least 1 other food allergy. For example, more than half of sesame-allergic patients have a peanut allergy, one-third have a tree nut allergy, one-fourth have an egg allergy, and one-fifth have an allergy to cow’s milk.

While it is important to note that our study did not assess the frequency of accidental sesame exposure due to unlabeled or confusingly labeled foods, our findings showed that sesame allergy affects more individuals than some other allergens for which mandatory allergen labeling is currently required by the FDA, including pine nuts and macadamia nuts.

C360: How do these findings advance the field of food allergy?

Dr Warren: These data provide up-to-date national estimates on the current population-level burden of sesame allergy among US children and adults, based on survey respondents from all 50 states and the District of Columbia. The current rates of sesame allergy in the United States were previously unknown, since the most recent estimates were based on data collected in 2008 by Scott Sicherer, MD, who also co-authored the present study.⁴ Those 2008 data indicated that sesame allergy reportedly affected 0.2% of US children and 0.1% of US adults.⁴ However, the prevalence estimates reported in that paper were based on only 3 children and 10 adults reporting sesame allergies.⁴ This limited the ability to examine specific characteristics of sesame allergy patients, including reaction symptoms, health care utilization, comorbidities, and demographic differences.

These small sample sizes are contrasted with the 206 children and 273 adults who reported a current sesame allergy in the present study, which in turn permitted a much deeper dive into the current population-level burden of sesame allergy in the United States. Consequently, the precise, nationally-representative estimates reported in the present manuscript are well-suited to inform ongoing regulatory rule-making by the FDA, as well as other potential policies related to sesame allergy.

C360: Why are these findings important to primary care providers and other general audiences?

Dr Warren: Even though sesame allergy is not considered one of the "big 8" food allergies (i.e. milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, and soybeans),⁵ sesame allergy still affects more than 1 million US children and adults and appears to be increasingly prevalent in the United States. Consequently, sesame is often included among the so-called “big 9” food allergens.⁶

In addition to indicating that sesame allergy may be more common than previously acknowledged, these data clearly show that sesame allergy can result in severe reactions, emergency department visits, and emergency treatment with epinephrine. However, under current law, sesame can appear unlabeled on packaging or labeled in a potentially confusing manner—such as "tahini", or “sesamum indicum” (its scientific name) —possibly increasing the risk of accidental ingestion. Sesame is also a main ingredient of the increasingly popular Japanese spice blends/seasonings known as “shichimi togarashi” and “furikake”, which are often imported and therefore often do not have ingredients listed in English. In general, the present data suggest that greater awareness of sesame allergies is imperative, given their potential severity and the relatively large number of people affected.

C360: How can these findings be applied in clinical practice?

Dr Warren: These data provide insights into the distribution, determinants, and symptomatology of sesame allergy among US children and adults, which can be applied during clinical decision-making. The findings also suggest that many individuals who report sesame allergies and even experience potentially severe allergic reactions to sesame are not obtaining a clinical diagnosis of their allergy. Clinical confirmation of suspected food allergies is essential to reduce the risk of unnecessary allergen avoidance and to ensure food-allergic patients receive essential counseling and prescription of emergency epinephrine. Our data suggest that more than half of US children and adults who report a convincingly IgE-mediated reaction history to sesame are not seeking further confirmatory allergy testing, but rather are likely simply choosing to avoid the food. However, by not consulting with their physician about their allergy and obtaining a proper diagnosis, these individuals may be at greater risk of being unprepared for a sesame-allergic reaction. Such individuals may also continue to avoid sesame even when they develop tolerance to it, which may increase anxiety and impair their quality of life unnecessarily as they actively avoid an allergen they have already outgrown. 

Christopher Warren, PhD, is an epidemiologist affiliated with the Center for Food Allergy & Asthma Research, Northwestern University Feinberg School of Medicine, and Ann & Robert H. Lurie Children's Hospital of Chicago in Illinois.

—Christina Vogt

References:

1. Warren CM, Chadha AS, Sicherer SH, Jiang J, Gupta RS. Prevalence and severity of sesame allergy in the United States. JAMA Network Open. 2019;2(8):e199144. doi:10.1001/jamanetworkopen.2019.9144.

2. Statement from FDA Commissioner Scott Gottlieb, MD, on the FDA’s new consideration of labeling for sesame allergies [press release]. US Food and Drug Administration. October 29, 2018. https://www.fda.gov/news-events/press-announcements/statement-fda-commissioner-scott-gottlieb-md-fdas-new-consideration-labeling-sesame-allergies. Accessed August 2, 2019.

3. Davidoff J. Illinois requires food manufacturers to label sesame allergen. WILL Illinois Public Media. July 30, 2019. https://will.illinois.edu/news/story/illinois-requires-food-manufacturers-to-label-sesame-allergen. Accessed August 2, 2019.

4. Sicherer SH, Muñoz-Furlong A, Godbold JH, Sampson HA. US prevalence of self-reported peanut, tree nut, and sesame allergy: 11-year follow-up. J Am Allergy Clin Immunol. 2010;125(6):1322-1326. https://doi.org/10.1016/j.jaci.2010.03.029.

5. What you need to know about food allergies. US Food and Drug Administration. https://www.fda.gov/food/buy-store-serve-safe-food/what-you-need-know-about-food-allergies. Page last updated September 26, 2018. Accessed August 2, 2019.

6. QA staff. ‘Big 8’ allergens to become big 9? Quality Assurance and Food Safety. https://www.qualityassurancemag.com/article/big-eight-allergens-may-become-big-nine/. October 29, 2018. Accessed August 2, 2019.