Nutrition Science and Everyday Application - beta v 0.1

164 ALICE CALLAHAN, PHD, HEATHER LEONARD, MED, RDN, AND TAMBERLY POWELL, MS, RDN
by injection with a device such as an EpiPen, and then person should seek immediate
medical attention. 1
Figure 3.19. Common food allergens: peanuts, dairy, wheat, eggs, and shrimp. At right, an
EpiPen, containing injectable epinephrine, is pictured.
The most common food allergies in the U.S. are caused by proteins in peanuts, tree nuts,
milk, shellfish, eggs, fish, wheat, soy and sesame. 4,5 A 2019 study reported that 19% of
adults in the U.S. believe they’re allergic to at least one food. After asking people about their
symptoms, the researchers estimated that the true incidence of food allergies is closer to
11%, while the remaining 8% of people likely have a food intolerance. 4
Food allergies are common in children, affecting about 8% of U.S. children, although
allergies can also develop later in life. 5 It’s common for young children to outgrow allergies
to egg, dairy, wheat, or soy, but peanut, tree nut, and shellfish allergies are often lifelong.
Recent research has found that letting babies eat common food allergens, particularly
peanut products, can prevent the development of allergies, perhaps by allowing the immune
system an early opportunity to learn to differentiate between food proteins and invading
pathogens. 6
If you think you may have a food allergy, it’s important to see an allergist to ensure
you have an accurate diagnosis. Food allergies are diagnosed based on symptoms after
consuming a food, specific IgE blood tests, and/or skin prick tests, where a tiny amount of
food protein is scratched onto the skin to test for a reaction. Blood and skin tests determine
whether a person is sensitized to an allergen, meaning that they’re producing IgE antibodies
to the food. However, the presence of IgE antibodies doesn’t definitively mean a person has
a food allergy; it’s common to have a positive IgE test but still be able to eat the food without
symptoms. The gold standard test for diagnosing is an oral food challenge—consuming a
small amount of the food and watching for signs of a reaction—although due to time, cost,
and risk, these are not always conducted. If you are diagnosed with a food allergy, you will
be counseled to strictly avoid the food and carry injectable epinephrine in case of accidental
consumption. Unlike with food intolerances, consuming even a small amount of food can
cause a serious reaction in those with food allergies. 1
There are some promising new therapies for treating food allergies that involve exposing
a person to small amounts of the allergen to try to teach the body to tolerate it. These don’t
cure the allergy completely but may reduce the risk of a severe allergic reaction. The first of
these therapies was approved by the U.S. Food and Drug Administration in January 2020. 7
There are blood tests available that claim to screen for as many as 90 to 100 food
allergies from one blood sample. These measure a different type of antibody called IgG,