Food allergies are scary, so scary that some school districts have banned nuts and peanut butter because an allergic child could come into contact with residue or crumbs and develop a potentially fatal reaction. These dangerous food allergies are relatively new. Forty years ago, peanut butter and jelly was standard cafeteria fare.

While the cause of food allergies is unknown, it is starting to look like our modern diet and hygiene practices such as the wide use of antibacterial soap and cleansers, has disturbed the natural population of bacteria that live in and on the human body, an important part of ourMicrobiome, making the body more vulnerable to food allergies.

Between 1997 and 2011 the rate of food allergies in children increased by about 50 percent.

The findings of a new study could be good news for the 15 million people in the US who are affected by food allergies, including one in every thirteen children. That’s roughly two children in every school classroom.

A bacterial population that protects against food allergen sensitization.

University of Chicago researchers found that changes in intestinal bacteria affected the development of food allergies in the lab. They used two groups of mice. One group had been bred to be free of gut bacteria, and the other group had been treated with antibiotics at birth, which reduced the levels of gut bacteria.

When the mice were then exposed to peanut allergens, both groups had a strong immune — allergic — response. They produced much higher levels of antibodies against the allergens than mice that had normal populations of gut bacteria.

“Environmental stimuli such as antibiotic overuse, high fat diets, caesarean birth, removal of common pathogens and even formula feeding have affected the microbiota with which we've co-evolved,” said senior author Cathryn Nagler in a statement. “Our results suggest this could contribute to the increasing susceptibility to food allergies.”

The mice were then given a mix of Clostridia bacteria, causing their allergen levels to fall, but a dose of another type of intestinal bacteria, Bacteroides, produced no response.

The researchers believe Clostridia were responsible for the lower allergen levels and may play a protective role against food allergens. Clostridia are a diverse class of bacteria found in abundance in humans. They live very close to the lining of the intestinal wall putting them in close contact with the immune system.

“We've identified a bacterial population that protects against food allergen sensitization,” stated Nagler. “The first step in getting sensitized to a food allergen is for it to get into your blood and be presented to your immune system. The presence of these bacteria regulates that process. ”

Dr. Nagler and her team are working on a way to use Clostridia to develop a new treatment that would protect people from developing food allergies or treat people with food allergies and have formulated a probiotic therapy based on their findings.

The study was published in the Proceedings of the National Academy of Sciences.