During his January 29 confirmation hearing, senators grilled Health and Human Services (HHS) secretary nominee Robert F. Kennedy Jr. about his opinions on everything from vaccines to the abortion pill mifepristone. But during the session, Kennedy also shared his opinions on the state of the U.S. food system, blaming environmental damage for the increase in childhood allergies.
“I know what a healthy kid looks like because I had so many of them in my family,” he said. “I didn't know anybody with a food allergy, peanut allergy. Why do five of my kids have allergies? Why are we seeing these explosions in diabetes, rheumatoid arthritis, neurological diseases, depression, all these things that are related to a toxic environment?"
In the past, Kennedy has suggested that aluminum in vaccines is responsible for allergies in children. “You wonder why a whole generation of children is allergic to stuff,” he said on the MP podcast in 2021. “It’s because we’re inducing allergies, pumping them full of aluminum.” (There is no credible evidence to suggest that’s true.)
While the environment might be a factor, there are a range of theories as to why people develop allergies—and why, exactly, there's been a recent increase. Here’s what doctors know so far.
Meet the experts: Catherine Monteleone, MD, is an allergist-immunologist at Rutgers Robert Wood Johnson Medical School. David Corry, MD, professor of medicine in the section of immunology, allergy and rheumatology at Baylor College of Medicine.
Why do people develop allergies?
There is a wide range of allergies—some can cause more minor symptoms like a runny nose, while others can lead to severe and potentially life-threatening reactions like anaphylaxis.
Allergic reactions are sparked by your immune system, which can overreact when you’re exposed to something harmless like dust, mold, or pollen, according to Johns Hopkins Medicine. That can cause the immune system to create antibodies to attack the allergen, leading to symptoms like wheezing, itchiness, and watery eyes. “Allergies occur because our body is fighting a ‘harmful’ substance,” says Catherine Monteleone, MD, an allergist-immunologist at Rutgers Robert Wood Johnson Medical School. “It’s part of the whole immune system—it’s just an overreaction.”
Common allergic reactions are linked to a specific antibody called immunoglobulin E (IgE). When a susceptible person is exposed to an allergen, their body can produce large amounts of similar IgE antibodies, which can lead to an allergic reaction the next time they’re exposed, according to Johns Hopkins Medicine.
Over-exposure to an allergen also raises the risk of allergies, says David Corry, MD, professor of medicine in the section of immunology, allergy and rheumatology at Baylor College of Medicine. "People living in very moldy houses or houses with overwhelming dust mite and cockroach infestation can get allergic to these agents," he says.
Do allergies have a purpose?
In most cases, allergies are the body’s over-reaction to a harmless substance, according to Houston Healthcare. Allergies are a part of your immune system’s natural defense mechanism, but they can cause inflammation throughout your body. If left untreated, that inflammation may raise your risk of developing certain diseases, as well as poor immune system health.
"Allergic responses are powerfully antimicrobial, and especially effective against parasites and fungi that can infect the body or airway," Corry says.
While pet danders, dust mites, and pollens are not infectious or harmful, your body may see them at the same time it comes into contact with bad things like fungi and parasites, sparking the reaction. These allergens might resemble fungi and parasites enough that your body is tricked into thinking they are alive and potentially harmful, Corry adds.
Why do people in the U.S. have so many allergies?
Nearly one in three American adults and one in four American children have some kind of allergy, according to data from the Centers for Disease Control and Prevention (CDC). This is an increase: Reported food allergies among children increased 18 percent from 1997 to 2007, per the CDC.
It’s not clear why Americans have so many allergies, but there are some theories. The leading theory is the so-called “hygiene hypothesis,” that suggests living conditions in the world are too clean and that kids aren’t exposed to enough germs that train their immune systems to tell the difference between things that are harmless and harmful, according to the American Academy of Allergy, Asthma, & Immunology (AAAAI).
Other theories suggest that certain medications—like some antibiotics and acetaminophen—rising obesity rates, and vitamin D deficiency may all contribute. But these haven't been proven so far.
It’s likely a combination of factors, including diet, Monteleone says. “People are much more exposed than when they ate a diet right out of the garden,” she says.
Can allergies be cured?
Most allergies can’t be cured, but there are a range of treatments to manage symptoms and even to lower the odds you’ll have a reaction at all. Those include medications like pills and nasal sprays, immunotherapy to train the immune system not to overreact to allergens, and epinephrine to ease symptoms of a severe allergic reaction, according to the Mayo Clinic.
“Sometimes allergies will go away,” Monteleone says. “When you have an allergy, we can treat it. But it doesn’t lead to a cure.”
If you’ve tried things in the past that didn’t work, Monteleone recommends consulting with a healthcare professional again. “There are a lot of new treatments, don’t give up,” she says.
