Could a Too-Clean Society Trigger a Rise in Food Allergies?

February 17, 2021

Systems in our body that protect us from toxic food may be involved in the dramatic rise in food allergies, say researchers

Rising rates of food allergies may be the result of environmental factors and a misfiring protection system, propose four immunobiologists from Yale University.

A paper published by the scientists in the journal Cell suggests an exaggerated activation of the body’s toxic food protection system in response to environmental factors is behind the increase.(1)

They write that as many as 8 percent of children in the United States have a potentially deadly response to what are classified as the major eight food allergens.

These are often referred to as the “Big 8” and include milk, eggs, wheat, soybeans, fish, crustacean shellfish, tree nuts, and peanuts.(2)

The U.S. Centers for Disease Control and Prevention reported a rising rate of food allergies in children from data gathered from 1997 to 2011.(5)

Researchers found that over a 14-year period, the rate of food allergies increased to 5.1 percent from 3.4 percent. According to the most recent data from 2016, that rate may have jumped again to 7.6 percent,(6) which means the rate has more than doubled in 19 years. The Yale immunobiologists propose this trajectory may be the result of an increasing amount of unnatural substances or environmental chemicals.(7)

Your Body Has a Food Quality Control System

Physicians and researchers are concerned about this increasing prevalence of  food allergies. The Yale researchers point toward the multiple sensory mechanisms your body uses to monitor what is consumed and how these affect allergies.(8)

These systems include smell, taste, and chemosensory processes established in the gut and impacted by your gut microbiome. The researchers argue that allergic responses play a role in the  body’s food quality control system. The system includes identifying and responding to food antigens, which can result in a lethal food allergy.

One prevailing theory for the rise in food allergies has been a “too clean” environment—called the hygiene hypothesis—in which children and adults are no longer exposed to natural pathogens in the environment, triggering the immune system to become hypersensitive.(9)

Writing in Clinical & Experimental Immunology in 2010, scientists expanded the explanation to include the presence of processed foods, dishwashing detergent, and other environmental chemicals, as well as a “too clean” environment with the absence of natural microbial exposure.

The Yale immunobiologists argue these all play a role in disrupting the internal food quality control system, designed to help protect your body from noxious chemicals and harmful substances. The group believes this theory may lay the groundwork for future research, treatment, or prevention. In a press release from Yale University, one of the authors of the new paper highlighted the problem researchers were facing.(10)

“We can’t devise ways to prevent or treat food allergies until we fully understand the underlying biology. You can’t be a good car mechanic if you don’t know how a normal car works,” said co-author Ruslan Medzhitov, Sterling professor of immunobiology and investigator for the Howard Hughes Medical Institute.

“One factor is increased use of hygiene products and overuse of antibiotics and, secondly, a change in diet and the increased consumption of processed food with reduced exposure to naturally grown food and changed composition of the gut microbiome,” Medzhitov said.

“Finally, the introduction of food preservatives and environmental chemicals such as dishwashing detergents introduced novel elements for immune systems to monitor.”

When your body detects toxins have been consumed, it also activates the parasympathetic nervous system, intended to help neutralize the health threat.(11) This response can trigger food allergies and a lack of natural threats can make the system hypersensitive.

The team believes the collective changes to the food supply and environment have effectively made the immune system respond to food proteins in the same way they would to protect against toxins.

Other Food Allergy Factors

Other theories that have been proposed for increased food allergies include overuse of medications used to reduce stomach acid, as these can alter your gastrointestinal microbiome.(16)

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