Researchers say junk food contains a compound linked to food allergies, but other experts say there are a variety of causes.
People's love of processed foods might be one reason for the stark increase in — and severity of — food allergies in the past few decades, a new study suggests.
Looking at a group of children ages 6 to 12, researchers from the University of Naples Federico II found that kids who had food allergies had higher levels of a compound associated with highly processed "junk" foods under their skin than kids with respiratory allergies or no allergies.
The potential culprits are called advanced glycation end products, or AGEs.
Glycation is what happens when a sugar molecule binds to a protein or fat under heat. This is what happens when you sear a steak to get a nice brown crust or fry a potato in oil.
In other words, they're great for flavor, but not all that good for you. And highly processed foods tend to contain higher levels of AGEs.
The existence of higher levels of AGEs among children with allergies might suggest a "missing link" in existing models of food allergies, according to Dr. Roberto Berni Canani, an associate professor of pediatrics at the Naples university and lead study investigator.
Another expert says the link may indeed be there, but other factors also contribute.
"Prior studies hypothesized that dietary sources of AGEs — commonly found in Western diets — may contribute to the increasing prevalence of food allergies. However, there are multiple contributors to the rising allergy incidence, and it's important that we understand all of the ways that our environment has shaped food allergy susceptibility," Dr. Wendy Sue Swanson, MBE, FAAP, a pediatrician at Seattle Children's Hospital and chief medical officer of Before Brands, told Healthline. "Processed foods may lack protein diversity, for example, but more research needs to be conducted to understand the exact role AGEs play in the development of food allergies."
Regardless of the exact cause, the reality is that food allergies are up almost 200 percent in the past 20 years, according to Dr. Tania Elliott, an associate attending physician at NYU Langone Health in New York and a national spokesperson for the American College of Allergy, Asthma, and Immunology.
"The cause is thought to be multifactorial, including both genetics and environment," she told Healthline.
Dr. Lakiea Wright, a physician in internal medicine and allergy and immunology at Brigham and Women's Hospital in Boston and the medical director at Thermo Fisher Scientific, agreed.
There are several primary factors thought to contribute to this rise in allergy incidence, she told Healthline. Here are some she enumerated:
- Timing of introduction of foods. Delaying the introduction of highly allergenic foods, such as peanuts and eggs, likely contributed to the rise in food allergies.
- Hygiene hypothesis. We're clean now, using antibacterial soaps and hand sanitizers. However, more exposures to microbes may have helped our immune system become more tolerant.
- Climate change. The way crops grow due to shifts in temperatures may make them more immunogenic and provoke the immune system, leading to the development of food allergies.
- Dietary patterns. People around the world eat more processed foods and less fruit and vegetables, which affects our gut microbiome.
- Genes and environment. This includes not only genetic makeup but in utero maternal exposures to allergens, including prenatal maternal diet, pollution, and chemicals.
Early antibiotic use may also have an influence on the gut and likelihood of developing allergies, added Dr. Douglas Jones, an allergy and immunology specialist at Rocky Mountain Allergy at Tanner Clinic in Utah.
"Researchers suggest that early antibiotic use changes the bacterial flora, which impacts the development of allergic diseases," he told Healthline. "Early use of antacids in children can also be problematic by changing the pH of the stomach and how the food that is digested is seen by the body once absorbed."
It's clear that allergies can surface thanks to a variety of factors, so how best to prevent or treat them?
Peanut allergies, for instance, appear to have both a genetic component and an environmental one. The genetic one you can't do much about, but it's likely that environmental approaches might help.
"The rise in peanut allergy is thought to be secondary to recommendations for avoidance of introduction of peanut into the diet until the age of 2," Elliott said. "Early introduction is now thought to be of paramount importance in the prevention of food allergies."
But attempts at oral immunotherapy, such as microdosing peanuts, have had mixed results.
That said, researchers are getting closer to a functional vaccine for peanut allergies.
That only leaves all of the other allergies.
For babies at least, early introduction of a variety of foods appears to be the way forward, Swanson said.
"Pediatricians are changing their tune around how to protect babies from developing a food allergy. They are advising that parents introduce potentially allergenic foods at an early age, typically starting at 4 to 6 months, when a baby's immune system is still in development," she advised. "I now recommend early introduction of a diverse diet of the most common potential allergenic foods fed regularly and over an extended period of time."
"This will build tolerance over time so that your baby can grow accustomed to a wide range of foods," she added.
For everyone else, short of a vaccine, "The main treatment for food allergies is to avoid what you are allergic to by reading labels and working closely with your doctor," Elliott said.