By Erin Blakemore,
Our bodies are designed to absorb healthy substances and reject poisonous ones to keep us healthy.
But what if the system that directs our body to accept or deny substances goes too far?
A group of immunobiologists thinks an overactive “food quality control system” might cause food allergies. In new research published in the journal Cell, they hypothesize that allergic immunity should be considered one of a group of defensive mechanisms the body has evolved to ward off noxious substances such as poison or spoiled food.
Though it’s still unknown how the body begins mounting an immune response to certain foods, the researchers think that tying it to the sensory systems that tell the body it’s okay to eat and digest a food might explain why food allergies are so common.
In a 2019 analysis, researchers found that nearly 19 percent of American adults believed they had food allergies, nearly half had a food allergy that began when they were adults, and 38 percent had visited the emergency room at least once for a food allergy-related reason.
In the past, researchers have hypothesized that the elimination of pathogens such as parasites through better hygiene led to hypersensitive immune systems because bodies don’t get the chance to develop immunities to infectious organisms. But even after many parasites were eliminated due to modern hygiene, allergies have continued to rise.
The team has an alternate explanation: As society has modernized, new substances have given the body new things to monitor, such as chemicals in dishwashing detergent, food preservatives and synthetic textiles. The food quality control system sees those unfamiliar substances as a threat and responds accordingly, the researchers write, overexciting the immune system and making it sensitive to nonthreatening foods.
“It’s guilt by association,” says Ruslan Medzhitov, an immunobiology professor at Yale University School of Medicine, investigator at the Howard Hughes Medical Institute and a co-author of the paper, in a news release.
“Dramatic changes in the modern environment have rendered allergic defenses ill suited to deal with the challenges of the increasingly ‘unnatural’ world,” the researchers write. By better describing the immune system and how it interacts with other systems like the sensory system, they say, scientists have a better chance of finally getting to the bottom of food allergies.
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