Weekend Reads | Food Allergies Across Racial and Socioeconomic Differences

by Kevin Schofield

This weekend's read is a new research report from Northwestern University looking at food allergies: specifically, the extent to which racial, ethnic, and socioeconomic differences exist in terms of who develops them.

Across the United States, it's estimated that 8% of children and 11% of adults have some form of food allergy. Those with food allergies can suffer from worse health as a result; they might struggle to maintain good nutrition, and they might also need to pay more for food to manage their food allergies. And yet, little information is available about who is more or less likely to have food allergies, either in general or specific common allergies, such as allergies to peanuts or shellfish.

Food allergies are hard to discuss, in part because there is so much bad or misleading information out there. Dieting and nutrition are big-revenue businesses in the U.S., and there are unfortunately plenty of companies ready to tell you that you suffer from food allergies in order to sell you their latest product or test, regardless of whether you've actually been diagnosed with one. There are also important differences between food "intolerances," which might, for example, irritate our digestive systems, and food "allergies" that could trigger migraines or even cause life-threatening allergic reactions; for example, by making it difficult or impossible to breathe. Food allergies tend to get a lot of play in news media and on social media, especially when it comes to our kids: We hear endlessly about serious peanut and shellfish allergies; gluten intolerance; egg, soy, and milk allergies; and other common food issues. Yet, more often than not, we're left guessing: Accurate diagnoses by trained medical professionals can be difficult and expensive.

While this research project purported to look at racial and ethnic differences in food allergies, it notes upfront an important issue that we've discussed before: Race and ethnicity don't have clear medical definitions. Rather, they are sociopolitically constructed based upon a set of external characteristics. Black, Hispanic, Asian, and white communities don't share exactly the same genetic makeup among themselves, nor do they share exactly the same culture (including their diet). They are very loosely defined groupings of people that tell us a bit about their genetics, their family lineage, their culture, their diet, and their socioeconomic status — but probably not enough to fully explain health features of those communities. In this case, we are looking for insights as to the origins of food allergies: Are they genetic, environmental, or epigenetic (in which environmental factors trigger specific genetic traits we might carry)? For this reason, the medical community has been moving away from using race and ethnicity in medical research, other than in cases like this, which look for disparate impacts. Even so, it's problematic as a medical research classification — as we will see.

The researchers surveyed 78,851 individuals: about 40,000 adults and 38,000 children. Participants self-reported their race and ethnicity, income level, what health insurance (if any) they had, and any food allergies: those either confirmed by a physician, or "convincing" because of the symptoms reported. Of those individuals, 5% had a physician-confirmed food allergy; 11.1% had one or more convincing food allergy. The rate of food allergies increased during childhood, plateaued during adulthood, and decreased in old age.

The researchers found that 10.6% of Black and Hispanic individuals had one or more confirmed or convincing food allergies. That was followed by 10.5% of Asians and 9.5% of white individuals, though those identifying as multiracial or multiethnic had by far the highest rate: 13.4%. Black children had the highest rate among youth, at 8.9%; Asian children had the lowest, at 6.5%. Specific food allergy rates (for example, peanuts, eggs, or shellfish) varied by race and ethnicity, and also by age; there were no clear patterns.

While this information is useful, it makes the picture even more confusing and suggests that we need to do much more research to understand the epidemiology of food allergies. Some of the numbers are baffling: For example, food allergies were highest among the middle class, while lower among both the highest and lowest income brackets. They were also highest among children enrolled in public health insurance (compared with both those with private insurance and those who are uninsured), which is a bit counterintuitive given that Medicare and Medicaid have notoriously poor access to medical specialists. The food allergy rates were also highest overall among those who identify as multiracial or multiethnic — a point we will revisit in a moment.

This leaves us at a loss to explain the differences. Are they genetically based? Perhaps, but again, race and ethnicity aren't precise enough to identify specific genetics. Are they environmental? Again, perhaps, but this study measured allergies to foods, not to environmental pollutants (or even pollens), and there isn't a clear line connecting environmental conditions to food allergies. Is it because of underdiagnosis of food allergies? The insurance data suggests otherwise: Those with the least access to health care (and thus medical diagnosis) have some of the highest rates. Is it related to the quality of food they consume? Again, the fact that the lowest income bracket has a lower rate of food allergies argues otherwise.

And here's a big, complicated mess of a question: Why does being multiracial or multiethnic give you a much higher likelihood of food allergies? Genetically, does being multiracial mean you collect genetic dispositions toward food allergies, or does it dilute the ones you might inherit by diversifying your genetics (or both)? Do people in multiracial or multiethnic households have a wider array of foods in their diet, thus exposing them to more lurking food allergies that would otherwise go undetected and undiagnosed? We simply don't know.

This research report tells us that food allergies have a disparate impact on certain racial and ethnic groups, even though it doesn't uncover why that is so. Clearly, there is much more work to be done to understand the dynamic we see here. But there is also important research needed to understand differences in how households manage food allergies across racial and ethnic communities, and whether there are best practices that should be adopted by families, social services, and the public health infrastructure to help reduce the health and economic impacts of food allergies.

Racial, Ethnic, and Socioeconomic Differences in Food Allergies in the US

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